3400/3500 top end swap on a 2.8

[Tonglebeak]

I think I'll just stick with 3100 gaskets for now, to be safe. Any idea on the pushrod dilemma?

[3100 MPFI]

When I built my high compression 3100, I used the camaro pistons, and gen 2 headgaskets, and they didn't hit.

Either way, I still think he is good to go. I think the problem might be only if the camaro pistons were used (does not matter in which case seeing he is leaving the block alone). I just want to be sure that I cover as much as I can. I don't want to say something is fine, and then there be damage from it. Just trying to cover my own ass some.

[Tonglebeak]

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&_trkparms=tab%3DWatching&viewitem=&item=260199269762&_trksid=p3907.m32

Seller says they're graphite. He still didn't say who manufactured them, but whatever :\

Those are indeed the large port, correct? I only see 3 holes in the UIM...

[3100 MPFI]

yes, those are the large port gaskets.

[IsaacHayes]

Any complete kit will have the crappy plastic LIM gaskets. Even if they have metal studs they will fail at some point. Those metal studs/discs only prevent user error from over torquing it.

[3100 MPFI]

I dont know about the aftermarket ones. The only lower intake manifold gaskets I will use are the GM ones.

[IsaacHayes]

GM ones still fail. They are plastic. The metal ones are the only ones I will ever mess with because taking apart the motor to fix a leak is not fun.

[Tonglebeak]

He says they're graphite...I asked if they were plastic, graphite and metal and he assured that they are graphite.

[3100 MPFI]

My GM ones are going on 5 years now, and no problems. The ones in my 1996 is going on 3 years (and more milege, and still no problems). The GM ones, even though they are plastic, if you install them correctly, then they will not fail. The original ones failed because the lower intake bolts would get overtorqued cracking the plastic. The GM ones have metal inserts that do not allow the materials to be compressed enough to crack.

[Tonglebeak]

I thought it was due to the DexCool eating away at the plastic. And why GM still uses that crap I have no idea...

[3100 MPFI]

DEXCOOL does not eat away at the plastic. It eats away at the GASKET MATERIAL that becomes exposed when the plastic crushes.

The updated GM gaskets have a different gasket material (it is now BLACK instead of BLUE), and it has metal inserts at the bolt holes so that when you tighten them down, it does not crush it.

[Tonglebeak]

You think that gasket kit should be good then, as long as it's installed properly and blah blah?

[3100 MPFI]

I think it will be just fine. The only thing is, the only lower intake gaskets I fully trust is the GM one. I would still keep an eye on it, but even if you do have to change it later on, it is pretty easy to do.

[Tonglebeak]

Ok

[IsaacHayes]

Then how come mine failed 3 times? Once factory, Once felpro, once dealership gaskets. The last one wasn't leaking but when I took it out it was separating from the silicone gaskets already.

All 3 sets none of them had any indication of cracking from bolts or pressure. They were all WARPED and separated allowing the silicone gasket to move and leak. The plastic will get brittle and fall apart after age, just like the rubber timing chain dampener turns to hard plastic and gets brittle... Only the first original gasket was cracking. The others were just warped from heat attacking the plastic.

My car has never had dexcool in it's life so that's not the cause on mine. How would dexcool attack the gasket material? It's silicone. And how would the plastic being cracked expose it? It's already exposed stock... lol

I've never had the silicone gasket fail, just the plastic that holds them there. That warps and pulls the silicone gasket's out of place.

Metal fel-pro is well, metal, so those sealing gaskets are not going to budge...