Miatapower List Archive

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Mail From: (email redacted)

anyone could describe what pinging sounds like?


tetsuo

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Mail From: Bill Cardell <(email redacted)>

(email redacted) wrote:
>
> anyone could describe what pinging sounds like?
>
> tetsuo

$$$$$$

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Mail From: Ron Van Vliet <(email redacted)>

(email redacted) wrote:

> anyone could describe what pinging sounds like?

In my best recollection of Corky's words to me, "Interpret *any*
uncharacteristic combustion-related noise as detonation." Better safe
than sorry...

I am replacing four pistons because of detonation-induced damage. In my
case, my oil pressure gauge was fluctuating as the sound occurred (as
per Barry Birdwell a good indication that detonation is occurring). This
happened exclusively at RPM's over 5000, and the sound I assumed was
oil-pressure-relief-valve-related must in fact have been detonation. By
reproducing the condition repeatedly in my efforts to troubleshoot what
I thought was a relief valve problem, I toasted the pistons. I was
running default FMII maps at the time, using supposed 92 octane gas. I
can only say that I had never previously encountered detonation at such
high RPM, and that the sound was unlike any detonation I've heard in
years of running cars hard on crappy 87 octane gas. Detonation in my
case produced a high frequency, soft, non-rattling sound (like an
aerated liquid sporadically being pushed through a thin hydraulic line)
-- not the characteristic "hammer on an anvil" sound I was expecting.
Since my problems didn't start until after a tank of the questionable
gas, I can only assume I hit a bad tank. A weak clutch may explain why
I didn't push the car hard enough at lower RPM's to cause detonation
there.

This probably doesn't need to be mentioned to most of you, but even when
running a system as sophisticated as the FMII on the default maps,
detonation is not an impossibility! To be safe, I'll be reinstalling my
J&S in the Spring (unless Bill's 1.6 ECU upgrade is available by then).

I'd welcome others' impressions on the sound of high RPM detonation,
BTW.

Ron Van Vliet

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Mail From: Kurt Summers <(email redacted)>

In my experience, it sounds like a small hammer smacking your engine block
in rapid succession. When severe, it will happen with every (or most
every) combustion event. Thus it varies w/ RPM.

At 06:27 PM 12/27/98 -0700, you wrote:
>I'd welcome others' impressions on the sound of high RPM detonation,
>BTW.
>
>Ron Van Vliet
>
>
>
Kurt Summers
'91 Silver
Tejas Miata Club
NOT ALL HORSEPOWER IS CREATED EQUAL
geocities.com/MotorCity/Speedway/5070

This read-only message was archived from a public mail list.
Mail From: (email redacted) (Mike Inman)


Whack an engine block with a little hammer,
if you've got lots of ping, you'll have lots of
little hammer noises.

M

At 04:31 PM 12/26/98 -0500, you wrote:
>
>anyone could describe what pinging sounds like?
>
>
>tetsuo
>