Miatapower List Archive

This read-only message was archived from a public mail list.
Mail From: "Jess Gypin" <(email redacted)>


Laid bare?? Hmmmmmmmm.........

At least when my 15 minutes of fame is over, I can be remembered a has been
Link groupie ;-)

(oh no! not another label!!)

Jess
----- Original Message -----
From: "Richard Dekker" <(email redacted)>
To: <(email redacted)>; <(email redacted)>; <(email redacted)>
Cc: "Ray Ayala" <(email redacted)>
Sent: Wednesday, June 13, 2001 6:10 AM
Subject: Re: [Fwd: Re: Rotten gas, reducing timing]


>
> Hear it comes.....it's finally laid totally bare....down to the bone.
>
> First it was turbochargers versus superchargers...Norm versus Corky...Link
> versus Tec II...Shiv versus Ray...Mark versus Jess...Mel against the whole
> list...US water - er beer versus Canadian beer....home brew versus
> micro-brew...but it always condesnes simply to Edmonton versus Calgary...
> ;-]
>
> Matt...you wouldn't be the Datsun 510 ice racer / slalomer Matt Beaubien
> that I remember up until a few years ago?
>
> Richard
> Edmonton, Alberta
>
> ----- Original Message -----
> From: "Marcel Rivet" <(email redacted)>
> To: "Matt Beaubien" <(email redacted)>; "miata" <(email redacted)>
> Cc: "Ray Ayala" <(email redacted)>
> Sent: June 11, 2001 10:17 PM
> Subject: RE: [Fwd: Re: Rotten gas, reducing timing]
>
> > (formerly Edmonton, Alberta)
>
> See there's the problem.
>
> Marcel
> Calgary, Alberta
>
> Just kidding. I've just noticed a certain number of challenges being flung
> back and forth between various parties. It seems that the fun factor Mel
> keeps mentioning sometimes is forgotten. I think often it is simply a
matter
> of wording that comes across in a manner which is harsher then intended. I
> know I've had a tendency at times to type faster then I can really think.
> Either way I look forward to your input in the future.
>
> > -----Original Message-----
> > From: Matt Beaubien [mailto:(email redacted)]
> > Sent: June 11, 2001 10:20 PM
> > To: Marcel Rivet; miata
> > Cc: Ray Ayala
> > Subject: Re: [Fwd: Re: Rotten gas, reducing timing]
> >
> > Marcel,
> >
> > I thought I was being pretty civil. I don't discredit any of the work
Ray
> > has done on the Link, but I felt it my comments were necessary to
provide
> > some backup. I had stated before that the camdrive was not a
significant
> > source of error before and even provided some worst case numbers for
> > transmission error, torsionals, and crank acceleration (from actual
> > data...). Take a look in the archives. No one ever provided
> contridicatary
> > data/evidence.
> >
> > I believe I'm generally pretty friendly...
> >
> > Matt.
> > Dearborn, MI (formerly Edmonton, Alberta)
>
>
>
>

This read-only message was archived from a public mail list.
Mail From: "Ray Ayala" <(email redacted)>


Two separate pieces of evidence. Look at the waveforms of the CAS signals
in the manual. What I have is timing data captured by the ECU for the
signal edges that shows the phenomenon I described. But since that data
alone could be due to either rotational nonlinearity or CAS drive
nonlinearities I looked at the cam drive system using a strobe light to see
which it was. It turned out to be some of both.

----- Original Message -----
From: "Matt Beaubien" <(email redacted)>
To: "Ray Ayala" <(email redacted)>
Cc: "miata" <(email redacted)>
Sent: Tuesday, June 12, 2001 9:48 PM
Subject: Re: [Fwd: Re: Rotten gas, reducing timing]


> Ray,
>
> So do you have any numbers to support this claim? Without data, stating
> that non-linear rotation (i.e. angular acceleration/torsionals) is pure
> conjecture.
>
> Several people have offered various explanations (belt stretch, crank
> accleration, crank twist etc) for explaining what's going on, but no one
has
> provided any data.
>
> I've been involved in failure analysis/redeisgn of some automotive parts,
> and I've scanned some message boards to read what people have to say.
They
> like to start offering explanations for why the parts are failing, and
well
> over 99% of the time, they're completely off base. Without doing any
> testing or having good supporting documentation, one is on very shaky
ground
> when it come to explaining observed phenomena.
>
> Case in point: TEC II vs Link and jagged curves. Some say that the TEC II
> has smoother curves because of increased timing accuracy. They may also
say
> it's because of a stronger spark. They may say it's better tuned. Who
> knows? There's just so many variables involved that it is silly for
someone
> to state that it's because of such-and-such _without_ doing testing (i.e.
> scientific method).
>
> I could argue that the curves are smoother because the ECU is closer to
all
> the signals so there's less delay in processing them. I'd be just as
> correct as someone who states it's because of stronger spark until proven
> otherwise. Unitl you can turn-on, turn-off, and turn-on again the
phenomena
> you are trying to understand, you can't state what the cause/fix is (run
the
> TEC II off the CAS and/or have it fire stock 1.6 coils and/or command same
> PW and ign timing on a TEC and Link and measure actual timing/AFR/power
> etc....).
>
> My two bits...
>
> Matt.
>
> ----- Original Message -----
> From: "Ray Ayala" <(email redacted)>
> Cc: "miata" <(email redacted)>
> Sent: Tuesday, June 12, 2001 12:40 AM
> Subject: Re: [Fwd: Re: Rotten gas, reducing timing]
>
>
> >
> > The non-linear rotation rate has nothing to do with crank twist ... just
> the
> > fact that the flywheel isn't infinitely heavy. As for twist and
resultant
> > ringing, maybe you haven't seen the pictures of what happens to turbo
> Miata
> > oil pumps when you lighten the damper a bit. Maybe somebody remembers
> where
> > they are.
> >
> > ----- Original Message -----
> > From: "Matt Beaubien" <(email redacted)>
> > To: "Ray Ayala" <(email redacted)>
> > Cc: "miata" <(email redacted)>
> > Sent: Monday, June 11, 2001 9:34 PM
> > Subject: Re: [Fwd: Re: Rotten gas, reducing timing]
> >
> >
> > > Ray,
> > >
> > > I still think you're barking up the wrong tree...
> > >
> > > Worst case crank deflection is on the order of 0.5 DDA (degrees double
> > > amplitude). This essentially means that the twist from the very front
> of
> > > the crankshaft to the very back (flywheel) is 0.5 degrees. It is
> > reasonably
> > > linear, so you can assume that (once again) worst case error to cyl #4
> > from
> > > the front is ~0.375'. Chances are that it will be less than that, but
> it
> > > will be the same from one rotation to the next (assuming same engine
> speed
> > > and cylinder pressure, though these never change quickly enough from
one
> > > cycle to the next to matter).
> > >
> > > In one of your private emails (that I haven't had time to reply to)
> > > indicated that a forged crankshaft would aggrevate this twist that is
> > > causing timing error. If anything, it would reduce it. The
cranktrain
> > can
> > > be simplified to a spring-mass system, and the stiffness will vary a
bit
> > > from a cast iron crankshaft to a forged steel crankshaft. Steel is a
> bit
> > > stiffer than iron, and the density will be a bit greater, so the "k"
> value
> > > will be higher for the forging. When a load is applied (f=k*x, or
> x=f/k),
> > > the deflection "x" will be less. Definitely not an order of magnitude
> > more.
> > > The circuit analogy is an R-C circuit for the spinning masses, and
V=IR
> > for
> > > the force/deflection.
> > >
> > > You probably understand the electronics/programming side of things
> better
> > > than I do, but I can pretty certainly state that I know the mechanical
> > side
> > > of things better. No offence is meant, but we each have our own areas
> of
> > > expertise.
> > >
> > > Regards,
> > >
> > > Matt.
> > >
> > > ----- Original Message -----
> > > From: "Ray Ayala" <(email redacted)>
> > > Cc: "miata" <(email redacted)>
> > > Sent: Monday, June 11, 2001 7:25 PM
> > > Subject: Re: [Fwd: Re: Rotten gas, reducing timing]
> > >
> > >
> > > >
> > > > And then there's the non-linear crank rotation rate under heavy
load.
> > > > The Link computes ign firing time as a percentage of the time
between
> > > > BDC and TDC (1/18th for 10 deg). 1/18 of that time is a varying
> number
> > > > of crank degrees depending on rpm and load, and it also varies from
> one
> > > > car to another with flywheel weight.
> > >
> > >
> > >
> > > _________________________________________________________
> > > Do You Yahoo!?
> > > Get your free @yahoo.com address at mail.yahoo.com
> > >
> > >
>
>
> _________________________________________________________
> Do You Yahoo!?
> Get your free @yahoo.com address at mail.yahoo.com
>

This read-only message was archived from a public mail list.
Mail From: Bill Cardell <(email redacted)>


Matt,
FWIW, take a look at the Pokeee curves in my tales from the dyno. Link
curves don't have to be jagged.

Bill Cardell
(email redacted)
Flyin' Miata
flyinmiata.com
200mphmiata.net
1-800-FLY-MX5S (orders only)
1-970-242-3800 (tech)


-----Original Message-----
From: Matt Beaubien [mailto:(email redacted)]
Sent: Tuesday, June 12, 2001 10:49 PM
To: Ray Ayala
Cc: miata
Subject: Re: [Fwd: Re: Rotten gas, reducing timing]



Ray,

So do you have any numbers to support this claim? Without data, stating
that non-linear rotation (i.e. angular acceleration/torsionals) is pure
conjecture.

Several people have offered various explanations (belt stretch, crank
accleration, crank twist etc) for explaining what's going on, but no one has
provided any data.

I've been involved in failure analysis/redeisgn of some automotive parts,
and I've scanned some message boards to read what people have to say. They
like to start offering explanations for why the parts are failing, and well
over 99% of the time, they're completely off base. Without doing any
testing or having good supporting documentation, one is on very shaky ground
when it come to explaining observed phenomena.

Case in point: TEC II vs Link and jagged curves. Some say that the TEC II
has smoother curves because of increased timing accuracy. They may also say
it's because of a stronger spark. They may say it's better tuned. Who
knows? There's just so many variables involved that it is silly for someone
to state that it's because of such-and-such _without_ doing testing (i.e.
scientific method).

I could argue that the curves are smoother because the ECU is closer to all
the signals so there's less delay in processing them. I'd be just as
correct as someone who states it's because of stronger spark until proven
otherwise. Unitl you can turn-on, turn-off, and turn-on again the phenomena
you are trying to understand, you can't state what the cause/fix is (run the
TEC II off the CAS and/or have it fire stock 1.6 coils and/or command same
PW and ign timing on a TEC and Link and measure actual timing/AFR/power
etc....).

My two bits...

Matt.

----- Original Message -----
From: "Ray Ayala" <(email redacted)>
Cc: "miata" <(email redacted)>
Sent: Tuesday, June 12, 2001 12:40 AM
Subject: Re: [Fwd: Re: Rotten gas, reducing timing]


>
> The non-linear rotation rate has nothing to do with crank twist ... just
the
> fact that the flywheel isn't infinitely heavy. As for twist and resultant
> ringing, maybe you haven't seen the pictures of what happens to turbo
Miata
> oil pumps when you lighten the damper a bit. Maybe somebody remembers
where
> they are.
>
> ----- Original Message -----
> From: "Matt Beaubien" <(email redacted)>
> To: "Ray Ayala" <(email redacted)>
> Cc: "miata" <(email redacted)>
> Sent: Monday, June 11, 2001 9:34 PM
> Subject: Re: [Fwd: Re: Rotten gas, reducing timing]
>
>
> > Ray,
> >
> > I still think you're barking up the wrong tree...
> >
> > Worst case crank deflection is on the order of 0.5 DDA (degrees double
> > amplitude). This essentially means that the twist from the very front
of
> > the crankshaft to the very back (flywheel) is 0.5 degrees. It is
> reasonably
> > linear, so you can assume that (once again) worst case error to cyl #4
> from
> > the front is ~0.375'. Chances are that it will be less than that, but
it
> > will be the same from one rotation to the next (assuming same engine
speed
> > and cylinder pressure, though these never change quickly enough from one
> > cycle to the next to matter).
> >
> > In one of your private emails (that I haven't had time to reply to)
> > indicated that a forged crankshaft would aggrevate this twist that is
> > causing timing error. If anything, it would reduce it. The cranktrain
> can
> > be simplified to a spring-mass system, and the stiffness will vary a bit
> > from a cast iron crankshaft to a forged steel crankshaft. Steel is a
bit
> > stiffer than iron, and the density will be a bit greater, so the "k"
value
> > will be higher for the forging. When a load is applied (f=k*x, or
x=f/k),
> > the deflection "x" will be less. Definitely not an order of magnitude
> more.
> > The circuit analogy is an R-C circuit for the spinning masses, and V=IR
> for
> > the force/deflection.
> >
> > You probably understand the electronics/programming side of things
better
> > than I do, but I can pretty certainly state that I know the mechanical
> side
> > of things better. No offence is meant, but we each have our own areas
of
> > expertise.
> >
> > Regards,
> >
> > Matt.
> >
> > ----- Original Message -----
> > From: "Ray Ayala" <(email redacted)>
> > Cc: "miata" <(email redacted)>
> > Sent: Monday, June 11, 2001 7:25 PM
> > Subject: Re: [Fwd: Re: Rotten gas, reducing timing]
> >
> >
> > >
> > > And then there's the non-linear crank rotation rate under heavy load.
> > > The Link computes ign firing time as a percentage of the time between
> > > BDC and TDC (1/18th for 10 deg). 1/18 of that time is a varying
number
> > > of crank degrees depending on rpm and load, and it also varies from
one
> > > car to another with flywheel weight.
> >
> >
> >
> > _________________________________________________________
> > Do You Yahoo!?
> > Get your free @yahoo.com address at mail.yahoo.com
> >
> >


_________________________________________________________
Do You Yahoo!?
Get your free @yahoo.com address at mail.yahoo.com

This read-only message was archived from a public mail list.
Mail From: "Ralph W. Gould" <(email redacted)>


Matt,
The point I was attempting to make (and obviously failed to) is, that while
accepting whole heartedly that the timing belt does NOTstretch, based on
personal experience with jumped timing belts, and in support of several
lister's observations of belt "oscillations", that the semantical term of
"belt stretch" was in fact due to belt tooth deflection.I guess the answer
is no, barking up the wrong tree.
No attempt on my part to engage in a pissing contest. Belts don't "stretch"
and wood doesn't burn. No problem here. Just trying to find some logic in
explaining the observed/perceived
issue of spark scatter.
By the way, why should I (as recommended) change my timing belt every 60,000
miles?
Regards,
Ralph


----- Original Message -----
From: "Matt Beaubien" <(email redacted)>
To: "Ralph W. Gould" <(email redacted)>; "Ray Ayala" <(email redacted)>
Cc: "miata" <(email redacted)>
Sent: Wednesday, June 13, 2001 12:54 AM
Subject: Re: [Fwd: Re: Rotten gas, reducing timing]


> Ralph,
>
> About the only way you're going to have a synchronous belt jump time is
for
> teeth to shear or improper tensioner tension/dampening. If you take a new
> or used belt and try to "move" a tooth around, you will find that it is
very
> tough.
>
> There's cords that run through the belt that don't allow any perceptable
> elongation, even over time. Technically, even chains don't stretch, they
> elongate. Stretch suggests plastic deformation is taking place. If this
> happens, the chain would break in very short order. What is infact
> happening is the clearance between the pins and links is getting larger.
> The links are the same length, but the holes are bigger so the chain
appears
> longer.
>
> Matt.
>
> ----- Original Message -----
> From: "Ralph W. Gould" <(email redacted)>
> To: "Matt Beaubien" <(email redacted)>; "Ray Ayala" <(email redacted)>
> Cc: "miata" <(email redacted)>
> Sent: Tuesday, June 12, 2001 9:00 AM
> Subject: Re: [Fwd: Re: Rotten gas, reducing timing]
>
>
> > Matt,
> > I accept your cam belt drive expertise and your statement that belt
> > "stretch" is < 1*. Would you then comment on cam belt tooth "deflection"
> > prior to a "belt jumping" incident? Are their not intermittent shear
> forces
> > at work between belt and
> > belt tooth prior to the belt finding a new home in an
> > adjacent cam tooth or crank pulley valley? Or are cam belt jumping
> > incidents instantaneous in nature - no appreciable belt/tooth
deformation
> > prior to jump? My assumption has been that these deflections exist (
> perhaps
> > due to incorrect belt tension) .
> > So the real question is; is "belt stretch" a question of semantics or a
> > misguided childhood?
> >
> > Ralph
>
>
>
> _________________________________________________________
> Do You Yahoo!?
> Get your free @yahoo.com address at mail.yahoo.com
>

This read-only message was archived from a public mail list.
Mail From: Mark Peugeot <(email redacted)>



Maybe that is why they went to the crank trigger on the '99 and moved the
REF signal to the cam sproket.

Mark


On Wed, 13 Jun 2001, Ray Ayala wrote:

>
> Two separate pieces of evidence. Look at the waveforms of the CAS signals
> in the manual. What I have is timing data captured by the ECU for the
> signal edges that shows the phenomenon I described. But since that data
> alone could be due to either rotational nonlinearity or CAS drive
> nonlinearities I looked at the cam drive system using a strobe light to see
> which it was. It turned out to be some of both.
>
> ----- Original Message -----
> From: "Matt Beaubien" <(email redacted)>
> To: "Ray Ayala" <(email redacted)>
> Cc: "miata" <(email redacted)>
> Sent: Tuesday, June 12, 2001 9:48 PM
> Subject: Re: [Fwd: Re: Rotten gas, reducing timing]
>
>
> > Ray,
> >
> > So do you have any numbers to support this claim? Without data, stating
> > that non-linear rotation (i.e. angular acceleration/torsionals) is pure
> > conjecture.
> >
> > Several people have offered various explanations (belt stretch, crank
> > accleration, crank twist etc) for explaining what's going on, but no one
> has
> > provided any data.
> >
> > I've been involved in failure analysis/redeisgn of some automotive parts,
> > and I've scanned some message boards to read what people have to say.
> They
> > like to start offering explanations for why the parts are failing, and
> well
> > over 99% of the time, they're completely off base. Without doing any
> > testing or having good supporting documentation, one is on very shaky
> ground
> > when it come to explaining observed phenomena.
> >
> > Case in point: TEC II vs Link and jagged curves. Some say that the TEC II
> > has smoother curves because of increased timing accuracy. They may also
> say
> > it's because of a stronger spark. They may say it's better tuned. Who
> > knows? There's just so many variables involved that it is silly for
> someone
> > to state that it's because of such-and-such _without_ doing testing (i.e.
> > scientific method).
> >
> > I could argue that the curves are smoother because the ECU is closer to
> all
> > the signals so there's less delay in processing them. I'd be just as
> > correct as someone who states it's because of stronger spark until proven
> > otherwise. Unitl you can turn-on, turn-off, and turn-on again the
> phenomena
> > you are trying to understand, you can't state what the cause/fix is (run
> the
> > TEC II off the CAS and/or have it fire stock 1.6 coils and/or command same
> > PW and ign timing on a TEC and Link and measure actual timing/AFR/power
> > etc....).
> >
> > My two bits...
> >
> > Matt.
> >
> > ----- Original Message -----
> > From: "Ray Ayala" <(email redacted)>
> > Cc: "miata" <(email redacted)>
> > Sent: Tuesday, June 12, 2001 12:40 AM
> > Subject: Re: [Fwd: Re: Rotten gas, reducing timing]
> >
> >
> > >
> > > The non-linear rotation rate has nothing to do with crank twist ... just
> > the
> > > fact that the flywheel isn't infinitely heavy. As for twist and
> resultant
> > > ringing, maybe you haven't seen the pictures of what happens to turbo
> > Miata
> > > oil pumps when you lighten the damper a bit. Maybe somebody remembers
> > where
> > > they are.
> > >
> > > ----- Original Message -----
> > > From: "Matt Beaubien" <(email redacted)>
> > > To: "Ray Ayala" <(email redacted)>
> > > Cc: "miata" <(email redacted)>
> > > Sent: Monday, June 11, 2001 9:34 PM
> > > Subject: Re: [Fwd: Re: Rotten gas, reducing timing]
> > >
> > >
> > > > Ray,
> > > >
> > > > I still think you're barking up the wrong tree...
> > > >
> > > > Worst case crank deflection is on the order of 0.5 DDA (degrees double
> > > > amplitude). This essentially means that the twist from the very front
> > of
> > > > the crankshaft to the very back (flywheel) is 0.5 degrees. It is
> > > reasonably
> > > > linear, so you can assume that (once again) worst case error to cyl #4
> > > from
> > > > the front is ~0.375'. Chances are that it will be less than that, but
> > it
> > > > will be the same from one rotation to the next (assuming same engine
> > speed
> > > > and cylinder pressure, though these never change quickly enough from
> one
> > > > cycle to the next to matter).
> > > >
> > > > In one of your private emails (that I haven't had time to reply to)
> > > > indicated that a forged crankshaft would aggrevate this twist that is
> > > > causing timing error. If anything, it would reduce it. The
> cranktrain
> > > can
> > > > be simplified to a spring-mass system, and the stiffness will vary a
> bit
> > > > from a cast iron crankshaft to a forged steel crankshaft. Steel is a
> > bit
> > > > stiffer than iron, and the density will be a bit greater, so the "k"
> > value
> > > > will be higher for the forging. When a load is applied (f=k*x, or
> > x=f/k),
> > > > the deflection "x" will be less. Definitely not an order of magnitude
> > > more.
> > > > The circuit analogy is an R-C circuit for the spinning masses, and
> V=IR
> > > for
> > > > the force/deflection.
> > > >
> > > > You probably understand the electronics/programming side of things
> > better
> > > > than I do, but I can pretty certainly state that I know the mechanical
> > > side
> > > > of things better. No offence is meant, but we each have our own areas
> > of
> > > > expertise.
> > > >
> > > > Regards,
> > > >
> > > > Matt.
> > > >
> > > > ----- Original Message -----
> > > > From: "Ray Ayala" <(email redacted)>
> > > > Cc: "miata" <(email redacted)>
> > > > Sent: Monday, June 11, 2001 7:25 PM
> > > > Subject: Re: [Fwd: Re: Rotten gas, reducing timing]
> > > >
> > > >
> > > > >
> > > > > And then there's the non-linear crank rotation rate under heavy
> load.
> > > > > The Link computes ign firing time as a percentage of the time
> between
> > > > > BDC and TDC (1/18th for 10 deg). 1/18 of that time is a varying
> > number
> > > > > of crank degrees depending on rpm and load, and it also varies from
> > one
> > > > > car to another with flywheel weight.
> > > >
> > > >
> > > >
> > > > _________________________________________________________
> > > > Do You Yahoo!?
> > > > Get your free @yahoo.com address at mail.yahoo.com
> > > >
> > > >
> >
> >
> > _________________________________________________________
> > Do You Yahoo!?
> > Get your free @yahoo.com address at mail.yahoo.com
> >
>
>

This read-only message was archived from a public mail list.
Mail From: Ray Ayala <(email redacted)>


No doubt that's why they added the crank sprocket, but moving the CAS
from the back of the head to the cam sprocket was just for cost
reduction. The new crank sprocket has no more resolution than the old
CAS so it still has to rely on the same old time-estimation system of
ign timing that's used with the old CAS. It does have better
repeatability though. Here again is an example of the OEMs putting
money into solving a problem that some folks don't believe even exists.

Mark Peugeot wrote:
>
> Maybe that is why they went to the crank trigger on the '99 and moved the
> REF signal to the cam sproket.
>
> Mark
>
> On Wed, 13 Jun 2001, Ray Ayala wrote:
>
> >
> > Two separate pieces of evidence. Look at the waveforms of the CAS signals
> > in the manual. What I have is timing data captured by the ECU for the
> > signal edges that shows the phenomenon I described. But since that data
> > alone could be due to either rotational nonlinearity or CAS drive
> > nonlinearities I looked at the cam drive system using a strobe light to see
> > which it was. It turned out to be some of both.
> >
> > ----- Original Message -----
> > From: "Matt Beaubien" <(email redacted)>
> > To: "Ray Ayala" <(email redacted)>
> > Cc: "miata" <(email redacted)>
> > Sent: Tuesday, June 12, 2001 9:48 PM
> > Subject: Re: [Fwd: Re: Rotten gas, reducing timing]
> >
> >
> > > Ray,
> > >
> > > So do you have any numbers to support this claim? Without data, stating
> > > that non-linear rotation (i.e. angular acceleration/torsionals) is pure
> > > conjecture.
> > >
> > > Several people have offered various explanations (belt stretch, crank
> > > accleration, crank twist etc) for explaining what's going on, but no one
> > has
> > > provided any data.
> > >
> > > I've been involved in failure analysis/redeisgn of some automotive parts,
> > > and I've scanned some message boards to read what people have to say.
> > They
> > > like to start offering explanations for why the parts are failing, and
> > well
> > > over 99% of the time, they're completely off base. Without doing any
> > > testing or having good supporting documentation, one is on very shaky
> > ground
> > > when it come to explaining observed phenomena.
> > >
> > > Case in point: TEC II vs Link and jagged curves. Some say that the TEC II
> > > has smoother curves because of increased timing accuracy. They may also
> > say
> > > it's because of a stronger spark. They may say it's better tuned. Who
> > > knows? There's just so many variables involved that it is silly for
> > someone
> > > to state that it's because of such-and-such _without_ doing testing (i.e.
> > > scientific method).
> > >
> > > I could argue that the curves are smoother because the ECU is closer to
> > all
> > > the signals so there's less delay in processing them. I'd be just as
> > > correct as someone who states it's because of stronger spark until proven
> > > otherwise. Unitl you can turn-on, turn-off, and turn-on again the
> > phenomena
> > > you are trying to understand, you can't state what the cause/fix is (run
> > the
> > > TEC II off the CAS and/or have it fire stock 1.6 coils and/or command same
> > > PW and ign timing on a TEC and Link and measure actual timing/AFR/power
> > > etc....).
> > >
> > > My two bits...
> > >
> > > Matt.
> > >
> > > ----- Original Message -----
> > > From: "Ray Ayala" <(email redacted)>
> > > Cc: "miata" <(email redacted)>
> > > Sent: Tuesday, June 12, 2001 12:40 AM
> > > Subject: Re: [Fwd: Re: Rotten gas, reducing timing]
> > >
> > >
> > > >
> > > > The non-linear rotation rate has nothing to do with crank twist ... just
> > > the
> > > > fact that the flywheel isn't infinitely heavy. As for twist and
> > resultant
> > > > ringing, maybe you haven't seen the pictures of what happens to turbo
> > > Miata
> > > > oil pumps when you lighten the damper a bit. Maybe somebody remembers
> > > where
> > > > they are.
> > > >
> > > > ----- Original Message -----
> > > > From: "Matt Beaubien" <(email redacted)>
> > > > To: "Ray Ayala" <(email redacted)>
> > > > Cc: "miata" <(email redacted)>
> > > > Sent: Monday, June 11, 2001 9:34 PM
> > > > Subject: Re: [Fwd: Re: Rotten gas, reducing timing]
> > > >
> > > >
> > > > > Ray,
> > > > >
> > > > > I still think you're barking up the wrong tree...
> > > > >
> > > > > Worst case crank deflection is on the order of 0.5 DDA (degrees double
> > > > > amplitude). This essentially means that the twist from the very front
> > > of
> > > > > the crankshaft to the very back (flywheel) is 0.5 degrees. It is
> > > > reasonably
> > > > > linear, so you can assume that (once again) worst case error to cyl #4
> > > > from
> > > > > the front is ~0.375'. Chances are that it will be less than that, but
> > > it
> > > > > will be the same from one rotation to the next (assuming same engine
> > > speed
> > > > > and cylinder pressure, though these never change quickly enough from
> > one
> > > > > cycle to the next to matter).
> > > > >
> > > > > In one of your private emails (that I haven't had time to reply to)
> > > > > indicated that a forged crankshaft would aggrevate this twist that is
> > > > > causing timing error. If anything, it would reduce it. The
> > cranktrain
> > > > can
> > > > > be simplified to a spring-mass system, and the stiffness will vary a
> > bit
> > > > > from a cast iron crankshaft to a forged steel crankshaft. Steel is a
> > > bit
> > > > > stiffer than iron, and the density will be a bit greater, so the "k"
> > > value
> > > > > will be higher for the forging. When a load is applied (f=k*x, or
> > > x=f/k),
> > > > > the deflection "x" will be less. Definitely not an order of magnitude
> > > > more.
> > > > > The circuit analogy is an R-C circuit for the spinning masses, and
> > V=IR
> > > > for
> > > > > the force/deflection.
> > > > >
> > > > > You probably understand the electronics/programming side of things
> > > better
> > > > > than I do, but I can pretty certainly state that I know the mechanical
> > > > side
> > > > > of things better. No offence is meant, but we each have our own areas
> > > of
> > > > > expertise.
> > > > >
> > > > > Regards,
> > > > >
> > > > > Matt.
> > > > >
> > > > > ----- Original Message -----
> > > > > From: "Ray Ayala" <(email redacted)>
> > > > > Cc: "miata" <(email redacted)>
> > > > > Sent: Monday, June 11, 2001 7:25 PM
> > > > > Subject: Re: [Fwd: Re: Rotten gas, reducing timing]
> > > > >
> > > > >
> > > > > >
> > > > > > And then there's the non-linear crank rotation rate under heavy
> > load.
> > > > > > The Link computes ign firing time as a percentage of the time
> > between
> > > > > > BDC and TDC (1/18th for 10 deg). 1/18 of that time is a varying
> > > number
> > > > > > of crank degrees depending on rpm and load, and it also varies from
> > > one
> > > > > > car to another with flywheel weight.
> > > > >
> > > > >
> > > > >
> > > > > _________________________________________________________
> > > > > Do You Yahoo!?
> > > > > Get your free @yahoo.com address at mail.yahoo.com
> > > > >
> > > > >
> > >
> > >
> > > _________________________________________________________
> > > Do You Yahoo!?
> > > Get your free @yahoo.com address at mail.yahoo.com
> > >
> >
> >

This read-only message was archived from a public mail list.
Mail From: Bill Cardell <(email redacted)>


The question I'd like to see an answer to is why they used uneven tooth
spacing on the m2 crank trigger. 70-110-70-110. Is it just to screw the
aftermarket?

Bill Cardell
(email redacted)
Flyin' Miata
flyinmiata.com
200mphmiata.net
1-800-FLY-MX5S (orders only)
1-970-242-3800 (tech)


-----Original Message-----
From: Ray Ayala [mailto:(email redacted)]
Sent: Wednesday, June 13, 2001 12:07 PM
Cc: miata
Subject: Re: [Fwd: Re: Rotten gas, reducing timing]



No doubt that's why they added the crank sprocket, but moving the CAS
from the back of the head to the cam sprocket was just for cost
reduction. The new crank sprocket has no more resolution than the old
CAS so it still has to rely on the same old time-estimation system of
ign timing that's used with the old CAS. It does have better
repeatability though. Here again is an example of the OEMs putting
money into solving a problem that some folks don't believe even exists.

Mark Peugeot wrote:
>
> Maybe that is why they went to the crank trigger on the '99 and moved the
> REF signal to the cam sproket.
>
> Mark
>
> On Wed, 13 Jun 2001, Ray Ayala wrote:
>
> >
> > Two separate pieces of evidence. Look at the waveforms of the CAS
signals
> > in the manual. What I have is timing data captured by the ECU for the
> > signal edges that shows the phenomenon I described. But since that data
> > alone could be due to either rotational nonlinearity or CAS drive
> > nonlinearities I looked at the cam drive system using a strobe light to
see
> > which it was. It turned out to be some of both.
> >
> > ----- Original Message -----
> > From: "Matt Beaubien" <(email redacted)>
> > To: "Ray Ayala" <(email redacted)>
> > Cc: "miata" <(email redacted)>
> > Sent: Tuesday, June 12, 2001 9:48 PM
> > Subject: Re: [Fwd: Re: Rotten gas, reducing timing]
> >
> >
> > > Ray,
> > >
> > > So do you have any numbers to support this claim? Without data,
stating
> > > that non-linear rotation (i.e. angular acceleration/torsionals) is
pure
> > > conjecture.
> > >
> > > Several people have offered various explanations (belt stretch, crank
> > > accleration, crank twist etc) for explaining what's going on, but no
one
> > has
> > > provided any data.
> > >
> > > I've been involved in failure analysis/redeisgn of some automotive
parts,
> > > and I've scanned some message boards to read what people have to say.
> > They
> > > like to start offering explanations for why the parts are failing, and
> > well
> > > over 99% of the time, they're completely off base. Without doing any
> > > testing or having good supporting documentation, one is on very shaky
> > ground
> > > when it come to explaining observed phenomena.
> > >
> > > Case in point: TEC II vs Link and jagged curves. Some say that the
TEC II
> > > has smoother curves because of increased timing accuracy. They may
also
> > say
> > > it's because of a stronger spark. They may say it's better tuned.
Who
> > > knows? There's just so many variables involved that it is silly for
> > someone
> > > to state that it's because of such-and-such _without_ doing testing
(i.e.
> > > scientific method).
> > >
> > > I could argue that the curves are smoother because the ECU is closer
to
> > all
> > > the signals so there's less delay in processing them. I'd be just as
> > > correct as someone who states it's because of stronger spark until
proven
> > > otherwise. Unitl you can turn-on, turn-off, and turn-on again the
> > phenomena
> > > you are trying to understand, you can't state what the cause/fix is
(run
> > the
> > > TEC II off the CAS and/or have it fire stock 1.6 coils and/or command
same
> > > PW and ign timing on a TEC and Link and measure actual
timing/AFR/power
> > > etc....).
> > >
> > > My two bits...
> > >
> > > Matt.
> > >
> > > ----- Original Message -----
> > > From: "Ray Ayala" <(email redacted)>
> > > Cc: "miata" <(email redacted)>
> > > Sent: Tuesday, June 12, 2001 12:40 AM
> > > Subject: Re: [Fwd: Re: Rotten gas, reducing timing]
> > >
> > >
> > > >
> > > > The non-linear rotation rate has nothing to do with crank twist ...
just
> > > the
> > > > fact that the flywheel isn't infinitely heavy. As for twist and
> > resultant
> > > > ringing, maybe you haven't seen the pictures of what happens to
turbo
> > > Miata
> > > > oil pumps when you lighten the damper a bit. Maybe somebody
remembers
> > > where
> > > > they are.
> > > >
> > > > ----- Original Message -----
> > > > From: "Matt Beaubien" <(email redacted)>
> > > > To: "Ray Ayala" <(email redacted)>
> > > > Cc: "miata" <(email redacted)>
> > > > Sent: Monday, June 11, 2001 9:34 PM
> > > > Subject: Re: [Fwd: Re: Rotten gas, reducing timing]
> > > >
> > > >
> > > > > Ray,
> > > > >
> > > > > I still think you're barking up the wrong tree...
> > > > >
> > > > > Worst case crank deflection is on the order of 0.5 DDA (degrees
double
> > > > > amplitude). This essentially means that the twist from the very
front
> > > of
> > > > > the crankshaft to the very back (flywheel) is 0.5 degrees. It is
> > > > reasonably
> > > > > linear, so you can assume that (once again) worst case error to
cyl #4
> > > > from
> > > > > the front is ~0.375'. Chances are that it will be less than that,
but
> > > it
> > > > > will be the same from one rotation to the next (assuming same
engine
> > > speed
> > > > > and cylinder pressure, though these never change quickly enough
from
> > one
> > > > > cycle to the next to matter).
> > > > >
> > > > > In one of your private emails (that I haven't had time to reply
to)
> > > > > indicated that a forged crankshaft would aggrevate this twist that
is
> > > > > causing timing error. If anything, it would reduce it. The
> > cranktrain
> > > > can
> > > > > be simplified to a spring-mass system, and the stiffness will vary
a
> > bit
> > > > > from a cast iron crankshaft to a forged steel crankshaft. Steel
is a
> > > bit
> > > > > stiffer than iron, and the density will be a bit greater, so the
"k"
> > > value
> > > > > will be higher for the forging. When a load is applied (f=k*x, or
> > > x=f/k),
> > > > > the deflection "x" will be less. Definitely not an order of
magnitude
> > > > more.
> > > > > The circuit analogy is an R-C circuit for the spinning masses, and
> > V=IR
> > > > for
> > > > > the force/deflection.
> > > > >
> > > > > You probably understand the electronics/programming side of things
> > > better
> > > > > than I do, but I can pretty certainly state that I know the
mechanical
> > > > side
> > > > > of things better. No offence is meant, but we each have our own
areas
> > > of
> > > > > expertise.
> > > > >
> > > > > Regards,
> > > > >
> > > > > Matt.
> > > > >
> > > > > ----- Original Message -----
> > > > > From: "Ray Ayala" <(email redacted)>
> > > > > Cc: "miata" <(email redacted)>
> > > > > Sent: Monday, June 11, 2001 7:25 PM
> > > > > Subject: Re: [Fwd: Re: Rotten gas, reducing timing]
> > > > >
> > > > >
> > > > > >
> > > > > > And then there's the non-linear crank rotation rate under heavy
> > load.
> > > > > > The Link computes ign firing time as a percentage of the time
> > between
> > > > > > BDC and TDC (1/18th for 10 deg). 1/18 of that time is a varying
> > > number
> > > > > > of crank degrees depending on rpm and load, and it also varies
from
> > > one
> > > > > > car to another with flywheel weight.
> > > > >
> > > > >
> > > > >
> > > > > _________________________________________________________
> > > > > Do You Yahoo!?
> > > > > Get your free @yahoo.com address at mail.yahoo.com
> > > > >
> > > > >
> > >
> > >
> > > _________________________________________________________
> > > Do You Yahoo!?
> > > Get your free @yahoo.com address at mail.yahoo.com
> > >
> >
> >

This read-only message was archived from a public mail list.
Mail From: "Marcel Rivet" <(email redacted)>


The sad part is all those other issues have a possibility of being resolved.

Marcel
Calgary, Alberta

-----Original Message-----
From: Richard Dekker [mailto:(email redacted)]
Sent: June 13, 2001 6:10 AM
To: (email redacted); (email redacted); (email redacted)
Cc: Ray Ayala
Subject: Re: [Fwd: Re: Rotten gas, reducing timing]


Hear it comes.....it's finally laid totally bare....down to the bone.

First it was turbochargers versus superchargers...Norm versus Corky...Link
versus Tec II...Shiv versus Ray...Mark versus Jess...Mel against the whole
list...US water - er beer versus Canadian beer....home brew versus
micro-brew...but it always condesnes simply to Edmonton versus Calgary...
;-]

Matt...you wouldn't be the Datsun 510 ice racer / slalomer Matt Beaubien
that I remember up until a few years ago?

Richard
Edmonton, Alberta

----- Original Message -----
From: "Marcel Rivet" <(email redacted)>
To: "Matt Beaubien" <(email redacted)>; "miata" <(email redacted)>
Cc: "Ray Ayala" <(email redacted)>
Sent: June 11, 2001 10:17 PM
Subject: RE: [Fwd: Re: Rotten gas, reducing timing]

> (formerly Edmonton, Alberta)

See there's the problem.

Marcel
Calgary, Alberta

Just kidding. I've just noticed a certain number of challenges being flung
back and forth between various parties. It seems that the fun factor Mel
keeps mentioning sometimes is forgotten. I think often it is simply a matter
of wording that comes across in a manner which is harsher then intended. I
know I've had a tendency at times to type faster then I can really think.
Either way I look forward to your input in the future.

> -----Original Message-----
> From: Matt Beaubien [mailto:(email redacted)]
> Sent: June 11, 2001 10:20 PM
> To: Marcel Rivet; miata
> Cc: Ray Ayala
> Subject: Re: [Fwd: Re: Rotten gas, reducing timing]
>
> Marcel,
>
> I thought I was being pretty civil. I don't discredit any of the work Ray
> has done on the Link, but I felt it my comments were necessary to provide
> some backup. I had stated before that the camdrive was not a significant
> source of error before and even provided some worst case numbers for
> transmission error, torsionals, and crank acceleration (from actual
> data...). Take a look in the archives. No one ever provided
contridicatary
> data/evidence.
>
> I believe I'm generally pretty friendly...
>
> Matt.
> Dearborn, MI (formerly Edmonton, Alberta)

This read-only message was archived from a public mail list.
Mail From: "Matt Beaubien" <(email redacted)>


Ray,

I haven't been ignoring this (and other threads), but I've been busy working
on Miatas and enjoying the nice weather...

This crank twist you keep talking about is just not a factor. Manufacturers
have an upper limit of acceptable twist, and as I've mentioned before, it is
on the order of 0.5 degrees double amplitude (DDA). This is meausured by
either a multi tooth wheel on the front of the crank, or a non-contact laser
device. The 0.5 degree is the worst case variance from a steady-state
running condition. In other words, this value represents the total
deviation of the front of the crankshaft from a perfectly constant angular
velocity. If the crank speeds up or slows down from this value, it is due
to combustion/intertia forces and/or crank deflection.

The required spark could easily vary from cylinder to cylinder at various
loads because of differences in head/block cooling, manifold filling, etc.
Half a degree of twist from the very front of the crank to the very back of
the crank is not very much, and is absolute worst case. A statistical
analysis would yield a number less than that, and the difference between
throw #1 and #4 would be less again...

Matt.

----- Original Message -----
From: "Ray Ayala" <(email redacted)>
To: "Mark Peugeot" <(email redacted)>
Cc: "miata" <(email redacted)>
Sent: Tuesday, June 12, 2001 11:42 AM
Subject: Re: [Fwd: Re: Rotten gas, reducing timing]


>
> And the damper only suppresses the pump-killing ringing, not the initial
> twist that starts it. Since there is more relative twist between the
crank
> pulley and the rear cylinder than there is between the crank pulley and
the
> front cylinder, the ECU needs different timing offsets for each cylinder
as
> a function of load. AFAIK only the custom race version Motecs provide
that
> currently, but with the price of 32-bit ECUs coming down we may see it on
> the street before long.
>



_________________________________________________________
Do You Yahoo!?
Get your free @yahoo.com address at mail.yahoo.com

This read-only message was archived from a public mail list.
Mail From: "Matt Beaubien" <(email redacted)>


I'm the one... I miss the ice racing, but not the cold weather. The funny
thing is everyone here complains about how bad the weather is--it's a step
in the right direction for me. ;-)

I'm convinced that no matter where you go in the world, everyone complains
about taxes, the price of gas, and weather. I thought Detroit had the worst
roads until I visited Cuba. That was a completely different ball game.

Matt.
Dearborn, MI

----- Original Message -----
From: "Richard Dekker" <(email redacted)>
To: <(email redacted)>; <(email redacted)>; <(email redacted)>
Cc: "Ray Ayala" <(email redacted)>
Sent: Wednesday, June 13, 2001 8:10 AM
Subject: Re: [Fwd: Re: Rotten gas, reducing timing]


>
> Hear it comes.....it's finally laid totally bare....down to the bone.
>
> First it was turbochargers versus superchargers...Norm versus Corky...Link
> versus Tec II...Shiv versus Ray...Mark versus Jess...Mel against the whole
> list...US water - er beer versus Canadian beer....home brew versus
> micro-brew...but it always condesnes simply to Edmonton versus Calgary...
> ;-]
>
> Matt...you wouldn't be the Datsun 510 ice racer / slalomer Matt Beaubien
> that I remember up until a few years ago?
>
> Richard
> Edmonton, Alberta



_________________________________________________________
Do You Yahoo!?
Get your free @yahoo.com address at mail.yahoo.com

This read-only message was archived from a public mail list.
Mail From: "Matt Beaubien" <(email redacted)>


Which supports my contention that you can't compare a smooth TEC II dyno
plot to a Link plot, and say the TEC isn't jagged because of stronger spark,
greater accuracy etc. There's just too many variables to make deductions
like that.

Matt.

----- Original Message -----
From: "Bill Cardell" <(email redacted)>
To: "'Matt Beaubien'" <(email redacted)>; "Ray Ayala" <(email redacted)>
Cc: "miata" <(email redacted)>
Sent: Wednesday, June 13, 2001 12:47 PM
Subject: RE: [Fwd: Re: Rotten gas, reducing timing]


> Matt,
> FWIW, take a look at the Pokeee curves in my tales from the dyno. Link
> curves don't have to be jagged.
>
> Bill Cardell
> (email redacted)
> Flyin' Miata
> flyinmiata.com
> 200mphmiata.net
> 1-800-FLY-MX5S (orders only)
> 1-970-242-3800 (tech)



_________________________________________________________
Do You Yahoo!?
Get your free @yahoo.com address at mail.yahoo.com

This read-only message was archived from a public mail list.
Mail From: "Matt Beaubien" <(email redacted)>


Ralph,

Sorry if I came off pissy at all, I'm just trying to help everyone's
understanding of what's going on. I've _never_ said that there's not
scatter on a CAS system--I'm just trying to provide information on what
_won't_ cause this.

Manufacturers aim for dynamic timing errors of <2*. I don't have any
information on the Mazda engine so I can't comment on what its numbers are,
but they should be pretty close.

Belts break, that's why you change them... ;-). Hotter climates are worse.
You can look at the belt and get a general idea on its condition. The
failure mode is cracks that propage until a tooth (or teeth) shear off, or
it cracks through the back side of the belt and brakes. Don't be surprised
if you see manufacturers with 150k mile belt timing systems in the near
future...

Matt.

----- Original Message -----
From: "Ralph W. Gould" <(email redacted)>
To: "Matt Beaubien" <(email redacted)>; "Ray Ayala" <(email redacted)>
Cc: "miata" <(email redacted)>
Sent: Wednesday, June 13, 2001 1:30 PM
Subject: Re: [Fwd: Re: Rotten gas, reducing timing]


>
> Matt,
> The point I was attempting to make (and obviously failed to) is, that
while
> accepting whole heartedly that the timing belt does NOTstretch, based on
> personal experience with jumped timing belts, and in support of several
> lister's observations of belt "oscillations", that the semantical term of
> "belt stretch" was in fact due to belt tooth deflection.I guess the answer
> is no, barking up the wrong tree.
> No attempt on my part to engage in a pissing contest. Belts don't
"stretch"
> and wood doesn't burn. No problem here. Just trying to find some logic in
> explaining the observed/perceived
> issue of spark scatter.
> By the way, why should I (as recommended) change my timing belt every
60,000
> miles?
> Regards,
> Ralph



_________________________________________________________
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Get your free @yahoo.com address at mail.yahoo.com

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Mail From: "Marcel Rivet" <(email redacted)>


Cuba, I once spent 13 hours traveling just over 300 kms in Cambodia, Phnom
Phen to Batambang. That was bad. No bladder back up problems that day.

-----Original Message-----
From: (email redacted)
[mailto:(email redacted)]On Behalf Of Matt Beaubien
Sent: June 17, 2001 10:28 PM
To: Richard Dekker; (email redacted)
Subject: Re: [Fwd: Re: Rotten gas, reducing timing]



I'm the one... I miss the ice racing, but not the cold weather. The funny
thing is everyone here complains about how bad the weather is--it's a step
in the right direction for me. ;-)

I'm convinced that no matter where you go in the world, everyone complains
about taxes, the price of gas, and weather. I thought Detroit had the worst
roads until I visited Cuba. That was a completely different ball game.

Matt.
Dearborn, MI

----- Original Message -----
From: "Richard Dekker" <(email redacted)>
To: <(email redacted)>; <(email redacted)>; <(email redacted)>
Cc: "Ray Ayala" <(email redacted)>
Sent: Wednesday, June 13, 2001 8:10 AM
Subject: Re: [Fwd: Re: Rotten gas, reducing timing]


>
> Hear it comes.....it's finally laid totally bare....down to the bone.
>
> First it was turbochargers versus superchargers...Norm versus Corky...Link
> versus Tec II...Shiv versus Ray...Mark versus Jess...Mel against the whole
> list...US water - er beer versus Canadian beer....home brew versus
> micro-brew...but it always condesnes simply to Edmonton versus Calgary...
> ;-]
>
> Matt...you wouldn't be the Datsun 510 ice racer / slalomer Matt Beaubien
> that I remember up until a few years ago?
>
> Richard
> Edmonton, Alberta



_________________________________________________________
Do You Yahoo!?
Get your free @yahoo.com address at mail.yahoo.com

This read-only message was archived from a public mail list.
Mail From: "Ray" <(email redacted)>


I wasn't suggesting that it was a problem on typical Detroit iron. An
ordinary cast crank would probably snap in two it you twisted it one deg.
Most don't even tolerate .005" main bearing clearance.

----- Original Message -----
From: "Matt Beaubien" <(email redacted)>
To: "Ray Ayala" <(email redacted)>; "Mark Peugeot" <(email redacted)>
Cc: "miata" <(email redacted)>
Sent: Sunday, June 17, 2001 9:22 PM
Subject: Re: [Fwd: Re: Rotten gas, reducing timing]


>
> Ray,
>
> I haven't been ignoring this (and other threads), but I've been busy
working
> on Miatas and enjoying the nice weather...
>
> This crank twist you keep talking about is just not a factor.
Manufacturers
> have an upper limit of acceptable twist, and as I've mentioned before, it
is
> on the order of 0.5 degrees double amplitude (DDA). This is meausured by
> either a multi tooth wheel on the front of the crank, or a non-contact
laser
> device. The 0.5 degree is the worst case variance from a steady-state
> running condition. In other words, this value represents the total
> deviation of the front of the crankshaft from a perfectly constant angular
> velocity. If the crank speeds up or slows down from this value, it is due
> to combustion/intertia forces and/or crank deflection.
>
> The required spark could easily vary from cylinder to cylinder at various
> loads because of differences in head/block cooling, manifold filling, etc.
> Half a degree of twist from the very front of the crank to the very back
of
> the crank is not very much, and is absolute worst case. A statistical
> analysis would yield a number less than that, and the difference between
> throw #1 and #4 would be less again...
>
> Matt.
>
> ----- Original Message -----
> From: "Ray Ayala" <(email redacted)>
> To: "Mark Peugeot" <(email redacted)>
> Cc: "miata" <(email redacted)>
> Sent: Tuesday, June 12, 2001 11:42 AM
> Subject: Re: [Fwd: Re: Rotten gas, reducing timing]
>
>
> >
> > And the damper only suppresses the pump-killing ringing, not the initial
> > twist that starts it. Since there is more relative twist between the
> crank
> > pulley and the rear cylinder than there is between the crank pulley and
> the
> > front cylinder, the ECU needs different timing offsets for each cylinder
> as
> > a function of load. AFAIK only the custom race version Motecs provide
> that
> > currently, but with the price of 32-bit ECUs coming down we may see it
on
> > the street before long.
> >
>
>
>
> _________________________________________________________
> Do You Yahoo!?
> Get your free @yahoo.com address at mail.yahoo.com
>
>

This read-only message was archived from a public mail list.
Mail From: "Tom Graham" <(email redacted)>


Hi Matt,

I read in either Circle Track or Hot Rod (this would have been years ago so
I won't remember accurately) that resonance set up in a crank was violent
enough to lift the followers from the cam. Have you ever heard of something
like this?

Tom

----- Original Message -----
From: Matt Beaubien <(email redacted)>
To: Ray Ayala <(email redacted)>; Mark Peugeot <(email redacted)>
Cc: miata <(email redacted)>
Sent: Monday, June 18, 2001 12:22 AM
Subject: Re: [Fwd: Re: Rotten gas, reducing timing]


>
> Ray,
>
> I haven't been ignoring this (and other threads), but I've been busy
working
> on Miatas and enjoying the nice weather...
>
> This crank twist you keep talking about is just not a factor.
Manufacturers
> have an upper limit of acceptable twist, and as I've mentioned before, it
is
> on the order of 0.5 degrees double amplitude (DDA). This is meausured by
> either a multi tooth wheel on the front of the crank, or a non-contact
laser
> device. The 0.5 degree is the worst case variance from a steady-state
> running condition. In other words, this value represents the total
> deviation of the front of the crankshaft from a perfectly constant angular
> velocity. If the crank speeds up or slows down from this value, it is due
> to combustion/intertia forces and/or crank deflection.
>
> The required spark could easily vary from cylinder to cylinder at various
> loads because of differences in head/block cooling, manifold filling, etc.
> Half a degree of twist from the very front of the crank to the very back
of
> the crank is not very much, and is absolute worst case. A statistical
> analysis would yield a number less than that, and the difference between
> throw #1 and #4 would be less again...
>
> Matt.
>
> ----- Original Message -----
> From: "Ray Ayala" <(email redacted)>
> To: "Mark Peugeot" <(email redacted)>
> Cc: "miata" <(email redacted)>
> Sent: Tuesday, June 12, 2001 11:42 AM
> Subject: Re: [Fwd: Re: Rotten gas, reducing timing]
>
>
> >
> > And the damper only suppresses the pump-killing ringing, not the initial
> > twist that starts it. Since there is more relative twist between the
> crank
> > pulley and the rear cylinder than there is between the crank pulley and
> the
> > front cylinder, the ECU needs different timing offsets for each cylinder
> as
> > a function of load. AFAIK only the custom race version Motecs provide
> that
> > currently, but with the price of 32-bit ECUs coming down we may see it
on
> > the street before long.
> >
>
>
>
> _________________________________________________________
> Do You Yahoo!?
> Get your free @yahoo.com address at mail.yahoo.com
>
>

This read-only message was archived from a public mail list.
Mail From: "Tom" <(email redacted)>


right.. and neither is it a problem on your average (or even above average -
if you want to feel elite) import crank either. Scatter that is being
introduced into the system is obviously from other sources.

-tom

----- Original Message -----
From: "Ray" <(email redacted)>
To: "Matt Beaubien" <(email redacted)>; "Mark Peugeot"
<(email redacted)>
Cc: "miata" <(email redacted)>
Sent: Monday, June 18, 2001 2:43 AM
Subject: Re: [Fwd: Re: Rotten gas, reducing timing]


>
> I wasn't suggesting that it was a problem on typical Detroit iron. An
> ordinary cast crank would probably snap in two it you twisted it one deg.
> Most don't even tolerate .005" main bearing clearance.
>
> ----- Original Message -----
> From: "Matt Beaubien" <(email redacted)>
> To: "Ray Ayala" <(email redacted)>; "Mark Peugeot" <(email redacted)>
> Cc: "miata" <(email redacted)>
> Sent: Sunday, June 17, 2001 9:22 PM
> Subject: Re: [Fwd: Re: Rotten gas, reducing timing]
>
>
> >
> > Ray,
> >
> > I haven't been ignoring this (and other threads), but I've been busy
> working
> > on Miatas and enjoying the nice weather...
> >
> > This crank twist you keep talking about is just not a factor.
> Manufacturers
> > have an upper limit of acceptable twist, and as I've mentioned before,
it
> is
> > on the order of 0.5 degrees double amplitude (DDA). This is meausured
by
> > either a multi tooth wheel on the front of the crank, or a non-contact
> laser
> > device. The 0.5 degree is the worst case variance from a steady-state
> > running condition. In other words, this value represents the total
> > deviation of the front of the crankshaft from a perfectly constant
angular
> > velocity. If the crank speeds up or slows down from this value, it is
due
> > to combustion/intertia forces and/or crank deflection.
> >
> > The required spark could easily vary from cylinder to cylinder at
various
> > loads because of differences in head/block cooling, manifold filling,
etc.
> > Half a degree of twist from the very front of the crank to the very back
> of
> > the crank is not very much, and is absolute worst case. A statistical
> > analysis would yield a number less than that, and the difference between
> > throw #1 and #4 would be less again...
> >
> > Matt.
> >
> > ----- Original Message -----
> > From: "Ray Ayala" <(email redacted)>
> > To: "Mark Peugeot" <(email redacted)>
> > Cc: "miata" <(email redacted)>
> > Sent: Tuesday, June 12, 2001 11:42 AM
> > Subject: Re: [Fwd: Re: Rotten gas, reducing timing]
> >
> >
> > >
> > > And the damper only suppresses the pump-killing ringing, not the
initial
> > > twist that starts it. Since there is more relative twist between the
> > crank
> > > pulley and the rear cylinder than there is between the crank pulley
and
> > the
> > > front cylinder, the ECU needs different timing offsets for each
cylinder
> > as
> > > a function of load. AFAIK only the custom race version Motecs provide
> > that
> > > currently, but with the price of 32-bit ECUs coming down we may see it
> on
> > > the street before long.



_________________________________________________________
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Get your free @yahoo.com address at mail.yahoo.com

This read-only message was archived from a public mail list.
Mail From: Ray Ayala <(email redacted)>


Yes, but IIRC that was on a pushrod motor using a chain-driven cam, and
the chain slop exaggerates the effect. 30 yrs ago top fuel cranks were
observed (using a flywheel-triggered strobe light) twisting up to 45
deg. Which is not to suggest that a turbo Miata crank would twist even
a tenth of that, but it does illustrate the flexibility of forged
cranks. Cast cranks won't twist much without breaking.

Tom Graham wrote:
>
> Hi Matt,
>
> I read in either Circle Track or Hot Rod (this would have been years ago so
> I won't remember accurately) that resonance set up in a crank was violent
> enough to lift the followers from the cam. Have you ever heard of something
> like this?
>
> Tom
>
> ----- Original Message -----
> From: Matt Beaubien <(email redacted)>
> To: Ray Ayala <(email redacted)>; Mark Peugeot <(email redacted)>
> Cc: miata <(email redacted)>
> Sent: Monday, June 18, 2001 12:22 AM
> Subject: Re: [Fwd: Re: Rotten gas, reducing timing]
>
> >
> > Ray,
> >
> > I haven't been ignoring this (and other threads), but I've been busy
> working
> > on Miatas and enjoying the nice weather...
> >
> > This crank twist you keep talking about is just not a factor.
> Manufacturers
> > have an upper limit of acceptable twist, and as I've mentioned before, it
> is
> > on the order of 0.5 degrees double amplitude (DDA). This is meausured by
> > either a multi tooth wheel on the front of the crank, or a non-contact
> laser
> > device. The 0.5 degree is the worst case variance from a steady-state
> > running condition. In other words, this value represents the total
> > deviation of the front of the crankshaft from a perfectly constant angular
> > velocity. If the crank speeds up or slows down from this value, it is due
> > to combustion/intertia forces and/or crank deflection.
> >
> > The required spark could easily vary from cylinder to cylinder at various
> > loads because of differences in head/block cooling, manifold filling, etc.
> > Half a degree of twist from the very front of the crank to the very back
> of
> > the crank is not very much, and is absolute worst case. A statistical
> > analysis would yield a number less than that, and the difference between
> > throw #1 and #4 would be less again...
> >
> > Matt.
> >
> > ----- Original Message -----
> > From: "Ray Ayala" <(email redacted)>
> > To: "Mark Peugeot" <(email redacted)>
> > Cc: "miata" <(email redacted)>
> > Sent: Tuesday, June 12, 2001 11:42 AM
> > Subject: Re: [Fwd: Re: Rotten gas, reducing timing]
> >
> >
> > >
> > > And the damper only suppresses the pump-killing ringing, not the initial
> > > twist that starts it. Since there is more relative twist between the
> > crank
> > > pulley and the rear cylinder than there is between the crank pulley and
> > the
> > > front cylinder, the ECU needs different timing offsets for each cylinder
> > as
> > > a function of load. AFAIK only the custom race version Motecs provide
> > that
> > > currently, but with the price of 32-bit ECUs coming down we may see it
> on
> > > the street before long.
> > >
> >
> >
> >
> > _________________________________________________________
> > Do You Yahoo!?
> > Get your free @yahoo.com address at mail.yahoo.com
> >
> >

This read-only message was archived from a public mail list.
Mail From: "Matt Beaubien" <(email redacted)>


Tom,

Sounds to me like you're describing valve/lifter float. I'm not really sure
how the crank could do what you describe. It'd be cool though... ;-)

Matt.
----- Original Message -----
From: "Tom Graham" <(email redacted)>
To: "Matt Beaubien" <(email redacted)>
Cc: "miata" <(email redacted)>
Sent: Monday, June 18, 2001 11:59 AM
Subject: Re: [Fwd: Re: Rotten gas, reducing timing]


>
> Hi Matt,
>
> I read in either Circle Track or Hot Rod (this would have been years ago
so
> I won't remember accurately) that resonance set up in a crank was violent
> enough to lift the followers from the cam. Have you ever heard of
something
> like this?
>
> Tom



_________________________________________________________
Do You Yahoo!?
Get your free @yahoo.com address at mail.yahoo.com

This read-only message was archived from a public mail list.
Mail From: "Tom Graham" <(email redacted)>


This is a good crank story too. My Norton would flex the crank so much at
high revs the rollers in the bearings would wear the tips and ruin the
bearings in short order. The solution was a set of German bearings with
barrel shaped rollers. Then the intake valve would ping the piston! :^(

Nah, it was a crank article.

Tom

----Original Message Follows----

Tom,

Sounds to me like you're describing valve/lifter float. I'm not really sure
how the crank could do what you describe. It'd be cool though... ;-)

Matt.
----- Original Message -----
From: "Tom Graham" <(email redacted)>
To: "Matt Beaubien" <(email redacted)>
Cc: "miata" <(email redacted)>
Sent: Monday, June 18, 2001 11:59 AM
Subject: Re: [Fwd: Re: Rotten gas, reducing timing]


>
> Hi Matt,
>
> I read in either Circle Track or Hot Rod (this would have been years ago
so
> I won't remember accurately) that resonance set up in a crank was violent
> enough to lift the followers from the cam. Have you ever heard of
something
> like this?
>
> Tom



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