What am I doing wrong?

[2.8-350TBI]

I think with the MLS option that we have now, no... But thats just me.

The MLS seem really well built I know that. But with something solid like a copper HG, you wouldnt need to worry about blowouts, although I would think that it wouldnt seal as well as a multi-layer HG. decisions, decisions

[Jonpro03]

Now these 04+ GM gaskets... isn't that what I blew out the first time around? I never had the heads off of this motor when I bought it.

[3400-95-Modified]

true, but they were torqued and installed by a GM tech... for one, and two you were using factory head bolts. The combination of the studs and the gaskets installed properly should be good. After your first blow did you surface the heads by chance?

[Jonpro03]

No I didn't, just cleaned the old gasket material off. I plan on having the car down for a month or so, so a trip to the machine shop may be in order.

[3400-95-Modified]

That may be also the reason for the second failure... these aluminum heads warp very easily.

[Joseph Upson]

I mentioned earlier proper surfacing RA of aluminum heads if they had been surfaced. I wouldn't say aluminum heads warp easily without mentioning "with overheating", especially since the 3400 gaskets don't seem to be failing easily. This may be the result of the increased bore of the 3500 needing a stronger gasket to make up for the reduced gasket area under clamping pressure. The VVT motors have an increased cylinder head deck surface to go along with the increased bore so there is still about the same amount of gasket under clamping pressure around the cylinder bore which makes it more difficult to blow out under boost along with being MLS.

Copper gaskets from what I've read have a problem with leaking coolant from the passages.

[pocket-rocket]

Copper gaskets from what I've read have a problem with leaking coolant from the passages.

I've read the same.

[bszopi]

Just o-ring the block, use ARP studs, and be done with it. LOL

[Mars]

I'd say its something like poor block / head prep for the gaskets...

I've been running my 3500 turbo car for a while without a wideband, and just realise after intalling my AEM that I'm WAY lean, but I've been beating on it nonethless... haha

Resilient motors these are it would seem....

[Jonpro03]

I must be unlucky.

Maybe I'll just buy another motor ($150) and see if I am luckier.

[Z26-T]

I mentioned earlier proper surfacing RA of aluminum heads if they had been surfaced. I wouldn't say aluminum heads warp easily without mentioning "with overheating", especially since the 3400 gaskets don't seem to be failing easily. This may be the result of the increased bore of the 3500 needing a stronger gasket to make up for the reduced gasket area under clamping pressure.

So 3400/3500 hybrid is the best of both worlds? More deck surface area, slightly lower CR , and the better flowing heads.

[95SleeperAcheiva]

I don't mean to rain on anyone's parade here, but KISS method. I agree the FP gaskets are known for being weak, but did you deck the heads after the last HG popped? and/or did you atleast check them with a feeler gauge and "real" straight edge for "true"? Also it's rare on iron, but check the block too.

[TGP37]

I too have had my Felpro SD head gaskets fail. And they're even claimed to have 3 steel layers. I got the stock gaskets now.

You seem like you know what you are doing but, did you clean the thread passages in the block? I read up to 50% less clamping force can be experienced from improperly torquing the bolts.

Sorry you gotta go through this.....sucks.

[Jonpro03]

Wow, I sold this car a while ago!

The problem was the restrictive exhaust. The head gaskets were melting under extended WOT runs with high boost because cylinder temps got too high.

[TGP37]

LOL, I guess I should look at the time stamps...haha