Miata List Archive

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Mail From: mga (mga)

I am going to replace the o-ring on the crank angle sensor and thought it
was a good time to try the slight timing advance to gain 3 horsepower or so.
Can anyone comment on this? Do you gain any noticeable power? Does it
affect the running of the car otherwise? What is the best amount of advance
to add to the timing?
Anything I need to know when doing this procedure? (My mechanical abilities
are best suited to antiques like MGs; Miatas are a bit complex for my
limited talents.)

Don Scott
1991 Miata BRG, 1980 TR8
1962 MGA, 1973 MGB GT

This read-only message was archived from a public mail list.
Mail From: mga (mga)

John,
Thank you for the tip. I didn't know that such variations existed. What
about seals? My current Miata and the one I had before seem to spring oil
leaks from age-hardened seals- are there premium seals that will last longer?
Don Scott

At 06:30 AM 01/31/2004 -0800, you wrote:
>If you can get the size of the o-ring(take the old one to a bearing supply
house so they can size it for you) and replace it with one made of Viton in
lieu of the most common Buna-N it will probably never need to be replaced again.
>John
>
>mga <(email redacted)> wrote:
>I am going to replace the o-ring on the crank angle sensor and thought it
>was a good time to try the slight timing advance to gain 3 horsepower or so.
>Can anyone comment on this? Do you gain any noticeable power? Does it
>affect the running of the car otherwise? What is the best amount of advance
>to add to the timing?
>Anything I need to know when doing this procedure? (My mechanical abilities
>are best suited to antiques like MGs; Miatas are a bit complex for my
>limited talents.)
>
>Don Scott
>1991 Miata BRG, 1980 TR8
>1962 MGA, 1973 MGB GT
>
>________________________

This read-only message was archived from a public mail list.
Mail From: john.freas (John Freas)

Previously on Advancing timing, "mga" <(email redacted)> said...

> I am going to replace the o-ring on the crank angle sensor and thought it
> was a good time to try the slight timing advance to gain 3 horsepower or
so.
> Can anyone comment on this? Do you gain any noticeable power? Does it
> affect the running of the car otherwise? What is the best amount of
advance
> to add to the timing?

Having tried it on two different NA cars, I highly recommend the timing
advance. It's extremely easy to accomplish, and produces a noticable
improvement in low-end power, especially on 1.6 liter cars. I had been
running 16° on my car but on warm days it wanted 'Plus' grade gasoline (US
89 Octane) to keep from pinging. I backed it down to 14° when fuel prices
went up and noticed only a very slight decrease in pull, but I could run
regular unleaded again.

What's the best amount of timing to add? I would say in the winter you
could go with 16° and maybe not need to increase your octane intake, or if
that's not a problem for you, then go with it year-round. If you'd like to
keep running regular unleaded, then you may need to back it down to 14° if
it starts to ping. You'll notice it under heavy acceleration and/or warmer
days if it's going to happen.

The trick is that each car seems to have its own personality and knock
tolerance level. Some cars can run 18° on nothing but Plus, and others need
Premium to run at 16°. The only thing you can do is advance the timing and
keep your ears open for ping, then either adjust your timing or octane until
it goes away. My advice is to start in the 'middle' at 16° and see how the
car behaves. If it likes it OK, then cool. If it pings, either back off to
14° or buy more expensive gas. Finally, if you like the 16° and the car
doesn't need Premium already, you can try advancing to 18° to see how you
like that. That's about as far as I'd go.

> Anything I need to know when doing this procedure? (My mechanical
abilities
> are best suited to antiques like MGs; Miatas are a bit complex for my
> limited talents.)

You'll need a special tool: Miata.net part number NA-01-ppr-clp. $89.95
online, or you can just unbend your own from the little tray on your desk ;)

It's very easy, just follow the directions at
miata.net/garage/ignition.html#timing and you'll be fine.

-John
_______________________________________________
John Freas
Red '90 Base-ish #7690
Columbus, IN
Team Hakkapeliitta!!!
I love my Miata girl.
"Seat Heaters are a wonderful thing."