spark plugs always tell a good story

Status
Not open for further replies.
Joined
Aug 20, 2003
Messages
799
Location
Washington, DC
I have lived in 2.7L twin turbo engine for 40K miles mainly lubed with GC and I have seen boost as high as 20psi, seafoam showers once a year and fuel enhanced with numerous bottles of redline fuel system cleaner.

What story does this one tell you?

spark_005.jpg
 
Last edited:
Originally Posted By: zoomzoom
I am curious what is the small particle build up on the plug?


I've usually seen it more easily viewable, but combustion side coolant/HG leakage looks like that. I'd expect larger "salt" grains.
 
Reading plugs is not as easy as it used to be.
Gasoline is different with alcohol in it, and the many new additives.
Actually, you are only seeing if the heat range is approx. correct on the tip. The mixture reading is an annular ring near the bottom of the insulator.
And it matters WHEN the plug was pulled - right after what conditions. To properly read a plug, you have to 'cut clean' from full throttle.

But that plug looks fine. A bit warm and with expected deposits.
 
Some speckled build-up (hard to tell from this plug) can be aluminum from the piston, which will accumulate on the plug during detonation.
 
Looks good to me. A little rust on the hex, some normal deposits, all the insulator/electrode/mixture colors are normal. Full throttle cuts are only to check conditions at full throttle, mostly applicable to racing engines. If it were my engine, I'd inspect a little closer on the wear and other possible failure areas, but from that pic it looks like you could go another 40k.
 
Originally Posted By: OVERK1LL
Some speckled build-up (hard to tell from this plug) can be aluminum from the piston, which will accumulate on the plug during detonation.


I don't think this car has aluminum pistons?
 
Originally Posted By: chevrofreak
What kind of car? It's extremely rare for a car to have something other than aluminum pistons.


2001 Audi S4 2.7L V6...Engine design document states:

The pistons are forged to enable them to
withstand the high loads to which they are
subjected.

Would that show as a AL spike in UOA?

uoa-fall-2008.jpg
 
Last edited:
Originally Posted By: tom slick
That plug tells me that you use fuel system additives. I don't see signs of detonation, i.e. sparkles.


Tom, that is a good assessment. I pulled the plugs on my 00 Saturn the other day to replace them and mine were identical to the ones shown by the OP. Holding them up to the computer screen they are identical. During the time these plugs have been in, I used Shell V-power additive twice and Regane additive twice.
 
Originally Posted By: tom slick
That plug tells me that you use fuel system additives. I don't see signs of detonation, i.e. sparkles.


Redline SI fuels system treatment
 
Status
Not open for further replies.
Back
Top Bottom