Ideas on stoppin some pingin? (long)

[Tim Rogers]

Brian Jones wrote:

>>Hmmmm sooo if you have any detonation after some damage is done...
I'm guessing that the detonation problem will just continue?
Could there be any way that a valve is in tough shape and
Something is leaking in when it shouldn't be?<<

If the problem is that the valve or its seat got damaged, (via ingesting a
nut, bolt, washer, spark plug electrode, small farm animal, etc. and having
the offending item get caught between the valve and the seat causing damage
to the valve or the seat) the issue would be losing some of the intake
charge out the intake valve during the compression stroke, or some of the
combustion gasses out during the power stroke (either way, less power but no
knock.)   If the transgressing bit got caught in the exhaust valve, the
results could be the valve not seating, causing some exhaust gas to get
pulled in during the intake stroke (like a little more EGR but no biggie,)
losing  gasses during the power stroke or losing some of the mixture into
the exhaust stream during the compression stroke, causing reduced power and
possibly a backfire condition but again, no knock.
Unless you are pretty sure you have had something go for a ride inside your
combustion chamber, you can pretty well rule this stuff out.  If you think
it did happen, then a compression or leak down check would show which
cylinder had a damaged valve.
If your offending bit just damaged the head or piston causing a potential
hot spot, you would need someone with a Bor-O-Scope (sp?) to check the
combustion chambers for damage.

Tim Rogers
-93 NX T-top -needs motor work
-91 NX - Racecar-to-be
-75 Silverado - Rusty Beast
-01 Astro - Work Van, Tow Beast