piperporsche180944

After quite a few miles with the boost set at 22-26lbs of boost the inevitable happened. The car starting blowing white smoke, I figured my 1988 951 had a blown head gasket.


Survey says...

Head gasket was demolished..........

I couldnt help but to admire how nice the cylinder walls were.

Duck


Duck


Duck


Goose


Right now is a turning point for the 951... I really love the 4 cylinder, but this may be the perfect excuse to install a turbocharged LSX... What do you guys think?

refresh951

Hydro-lock is my bet. What did the gasket look like?

piperporsche180944

Pretty cool huh? I have been chatting with XSChop on a v8 swap, it may be in the works soon.

dizzyj

Go v8. It just is a great choice

lart951

well, I ran 21-23psi for nearly 4 years without issues, I say most likely detonation that's #4 cyl. what kind of gas or gas mixture were you using?

Scott H

A deckplate is looking more and more like a good investment.

blown 944

Sucks, looks like it may have been cracked at the top for some time and finally broke through.

A rear mount ls turbo setup would be pretty cool.

Tom M'Guinn

Sorry about that. I wonder if the 55# injectors at 3 bar with the stock pump had enough juice at 26psi to keep up? Were you running pump gas, race gas, e-85? Ignition timing gets pretty touchy at that level too -- wonder how aggressive those 951MAX chips are with timing? As fun as building a new engine can be, you can't beat the efficiency and ease of bolting in a solid used replacement motor (even a V8 I suppose). Good luck whichever route you go.

Techno Duck

What kind of headgasket were you using? Stock, wide fire, wide fire + o-ringed head, cometic? Just curious. Are you still going to need the 60-1?

carlege

You do seem to be very hard on your cars. I do notice LR MAF on that list of mods. What were the AFR's? Can the LR MAF account for the changes in boost like Rogues?

lart951

Carlena, 22-26psi on these blocks is a no no situation unless you are on race fuel and under perfect a/f ratio, I ran 21-23 psi with 10-15% xylene mix, but at that time xylene and toluene were available.

piperporsche180944

Its safe to assume I am one to push the limits. My AFRs were around 11.5-12.0 WOT. I have a piggyback that I used to adjust the tune.

lart951

what kind of fuel?

piperporsche180944

50/50 mix, 93/110.

I was running the stocker... And unfortunately it looks like Ill just remove the 60-1 off of my 1988 951 and toss it on my 1986. Im going to lartize all my little 4 banger mods off the 1988 if anyone is interested.

Rogue_Ant

Remember, AFR is only half the equation. The other half is timing...

I don't see any tell-tale signs of detonation. (he was running high octane fuel)
However, there was most likely way too much timing for that boot pressure/load, causing very high cylinder pressures, resulting in the failure.