For some reason when i got a heavy foot in my car a couple weeks ago, it over boosted and then I saw the infamous white smoke out the exhaust. I finally got some free time from college so i pulled the motor and then the heads, is this where head gaskets normally blow? since it was both back cylinders it is possible that i didn't get the torque right on them. here are a couple pics.


This was bent up like that before i pulled the head off!


Another angle


Driver side starting to go!

 

That looks about right. You might want to revisit your tune. Your either too aggressive with it, or something is starting to fail on your setup.

Ken R.

 

Well a couple weeks before this happened i had it on a dyno getting dialed in and was running into a problem with the valve springs. Fixed that and everything looked good on my wideband, so i figured it was good to go, guess not!

 

Did it start floating valves on you on the dyno or other times? Thats not good either. How does your timing look? Maybe your running just a little too much at a certain point in your tune? Good thing it just pushed the gasket and not worse. It will usually blow it out 1st at the point of least material, like in your case.

Ken R.

 

What kind of machining needs to be done(if any) to the block to run cometics mls gaskets
?

 

im running cometics with machined heads and real good clean up on the block side and a coating of copper spray on the gasket about 2 to 3 times until dry.

 

For cometics, the heads and block need to be perfectly clean. I wiped both of mine down with alcohol and a lint free towel after having the block decked and the heads milled. Also, remember not to get the natural oils from your hands on them, so wear powder free gloves.

 

Yeah I talked to the good folks at cometic and they said i should be fine to clean up the block surface with out using anything abrasive and that the surface that was put on the deck from factory should be good enough as long as there is no scratches or any thing. So i guess I will see how it goes! Ohh and what do you use the copper spray for????

 

Ran cometics without copper spray with no problems. Next time it knocks it will be a piston though instead of a head gasket....

 

I would reconsider going to a different gasket. Your current 1074's blew out for a reason. You should probably be glad it took out the gasket 1st. Like stated above, you now may need to start worrying about doing parts damage before the gasket actually goes. I've run the same set of 1074's for a couple of years now on the street and track and have run it up to 15psi on a number of occations with nitrous on top of that. They've never let go. I keep a close tab on the tune though.

Ken R.

 

They aren't 1074's, they are stock replacement felpro 9966pt's. And when i pulled the heads the back head bolts around the back cylinders on each side were looser than the rest, that with the heads being slightly warped is what i am guessing the problem was. The tune isn't really bad per say but i am going to pull a little timing out throughout the rpm range until i can get back to the dyno, a/f has been perfect on my wideband sooooo . IDK im gonna try it and see what happens.

 

You said it overboosted - how much? Unless your setup was tuned for the amount you over boosted to, especially on the stock computer, I'm betting your a/f wasn't spot on for a moment or two

Ugg I should be working on mine.

 

it went about 5lbs. over what it did on the dyno when i was getting it tuned. Its definitively possible that for a second or two that the a/f got wacked out. that with everything else i said before like proper torque and slightly warped heads were all factors that could have done it by themselves

 

Read back to my thread; Pretty much an identical issue. I had quite a bit of timing in it, overboosted on the big end on a cold day, and my vinyl water injection hose sprung a leak from the heat from the header in the middle of a test run on the street and pop went the gaskets. Funny thing was I was watching the wideband and saw it hit 12:1 or leaner and I let out IMMEDIATELY. Didnt matter. Went back and pulled some timing and put new 1074's and made sure the heads were torqued properly this time. Havent had a problem again, yet.