It'* the twin-charged '96 SSEi with the 4T80 swap. The first time it broke, the #4 hole let loose a huge bang, resulting in this:







And everything was o.k. It'* been another three or four weeks and I was tuning on it again and then this happened:





#4 again! The engine is beat... porcelain went all thru the top end, beat on all the pistons, ruined #4 and #5 cylinders. I am looking for a long block now, but wondering why #4????

The first thing I'll check is the injector and harness on #4. They are brand new Precision injectors, but I guess that doesn;t mean anything if it'* bad. The rear header is home made, unequal length, but #4 is the middle length of the three, not the longest or shortest. Neither #2 or #6 looks or looked lean before. When it blew, the O2'* were 11.4-11.8 on the rear and 10.8-11.2 on the front (which is why you see I was tuning left and right banks with injector skew) I only had about 5deg KR so I know it didn't run out of retard. But why is it only #4?????

The fuel rail is modified L36, inlet on the rear (2,4,6) with 4 being the second hole. I am at a loss untill I take it apart and explore the possibilities of fuel issues on that hole....

Wish me luck.

See? It'* possible to blow the headgaskets on a 3800!

Damn, that'* a crying shame. Hope you get settled with a new one...

here'* some food for thought...
http://cgi.ebay.com/ebaymotors/GM-3-...2991QQtcZphoto

Or, if you wanna get REALLY crazy
http://intense-racing.com/Merchant2/...egory_Code=PBF

Good luck!

Good luck

Oh, bad news Jeff. :(

I'm sure you will find the root cause and determine a solution.

We are all staying tuned for better results.

Being that cyl #4 is the center cylinder on the rear bank, it is my guess that it is the hottest cylinder of the bunch.

Jeff, how were you tuning when these two events happened :?:

doh! I can feel your engine'* pain

Top of second gear, getting on the highway. The engine is making 16psi. Same as I dyno'd it, A/F is richer now than it was then. Both nights were cool, when the h.g blew it was 26deg out. The wb was in the front both times, which kind of sucks. I just had it in hte rear last week tuning the rear and I had it in the 11.4-11.8 range. I put it in the front with 5% front skew and the front was 10.0-10.8. I changed the front to 2.5% skew and brought it closer to 10.8-11.2. I was going to give the front 1.5% skew, but didn;t get that far........

I still think #4 injector or wiring harness is bad. The car runs great under no load, no skip, no vacuum leaks, no nothing. Manifold vac at idle is 20-21".

Yikes. Not sure what else to say. Makes our weekend look easy.

Why OEM head gaskets????? I didn't think they could handle over 13 or so regularly...

MLS FTW!!!! Never blown an MLS gasket, on upwards of 22lbs of boost.....