Does this look like what I think it looks like?

[Captn]

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It looks like one of my pistons is cracked?

 

[TylerAdamson]

It appears as though we're looking down through the spark plug well and that would be the top of your piston.

 

[transparentdsm]

yeah that looks like a valve head with the edges missing.


edit: turn the crack to top dead center and poke it with a metal hanger or something to see if it moves around in here.

 

[TylerAdamson]

I don't think that's a valve, I think its carbon build up on the piston.

 

[IncorpoRatedX]

left side looks like carbon, right side looks clean, try checking compression... /ubbthreads/images/graemlins/dunno.gif

 

[Captn]

Compression checks out, car runs like crap.... I can barely get it to move. Was doing some idle tuning and got my airrevs right and combft near 0 but as soon as I give it throttle it just about dies.

this is cylinder #1 at TDC

 

[marvinmadman]

E85 tar build up?

 

[gvr4ever]

If your piston was cracked, your compression wouldn't be okay. Looks like carbon build up, but in one spot?

Check fuel and spark. You can use the logger to disable fuel injectors one at a time.

 

[Captn]

Running pump gas, I will look into fuel spark.

 

[marvinmadman]

No other pistons look the same?

 

[Captn]

Cylinder 2 had something similar but its not as bad

 

[transparentdsm]

The dish look in the carbon made me think it was a valve. There would be 0 compression if it was a valve. Maybe some more info on the build. What kind of plugs are yoi using?

 

[marvinmadman]

Don't won't to sound stupid but you do know cylinder #1 is closest to the timing belt right?

 

[Captn]

Yes 1 is closest to timing belt I am using the ngk 8's

Manley pistons

 

[transparentdsm]

whats your gap?

 

[marvinmadman]

Pull the brake booster hose and see if that looks OK. I've seen a severe case when brake fluid made its way into there and caused something similar.

 

[slugsgomoo]

NGK BR8ES seem like an awfully cold plug for pump gas, why aren't you running 7's?

 

[Captn]

the gap was around .26 I changed them to .28

 

[slugsgomoo]

what's the setup mod wise, what are you logging and tuning with?

big factory gap on two step colder plugs on pump sounds like it wouldn't be that great to me.

 

[transparentdsm]

yeah get some 6's and gap them at .028 try that.