Who can read a headgasket?

Wow!  Lots of feedback here.  I'll try to work through it.

I measured the gaskets and the cylinders.  These are the proper gaskets.  This is the small bore 3.5.

I will get a straight edge on the heads and on the block to see what I can see.

Yes, several of the firerings are destroyed.

Tune is conservative and NOT a max power tune.  I have not noticed any detonation or anything.

Bad gas is a possibility, but this thing shouldn't need anything special.  It's a mini van engine (lolz).

I'll go back through and see what questions I missed.

The studs are threaded a good 1/4more than needed.  No topping out on the stud.

The guy that originally built the 1st iteration of this engine said: get a cometic gasket.  That's what he built it for and ne er had issues.

Guess I'm spending all the monies on head gaskets.

I also ordered a dial indicator with bridge, new feeler gauges, and a new straight edge.  I want this engine to last years!

NOHOME said:

Heads have been skimmed

Any chance you ran out of thread on the studs before you hit the torque setting?

Skimmed head and new studs a tad bit longer?

That was my thought!

Some engines have a thick enough heads to take fairly extreme shaving - c. 0.100" on TR2-TR4, IIRC, and that could result in enough stud sticking up past the head that you'd bottom on the threading and think you had the correct torque value when you didn't. Longer threading, or shorter studs or a thicker head gasket would remedy that (the latter would reduce compression ratio, of course).

No matter the bolt, lets say 1/2" that breaks at 10,000lbs of tensile pulling.  It doesn't matter if the bolt has 1" or 3" of thread engaged in the hole, you're never going to get more strength that you did when there was 1/2" (the bolt diameter) engaged.  So trim 1/4" off the tip of the bolt and see if it feels different.

This applies to all bolts.

In reply to 914Driver :

That doesn't help much with studs, does it?  Assuming the studs bottom out on the shank and not the bottom of a threaded hole.

I do not remember if these engines had open or closed head bolt bosses.

Pete. (l33t FS) said:

In reply to 914Driver :

That doesn't help much with studs, does it?  Assuming the studs bottom out on the shank and not the bottom of a threaded hole.

I do not remember if these engines had open or closed head bolt bosses.

What I'm trying to say is that the studs have way more threads left than the nut.  It isn't bottoming out.

They bottom on the block.  They have a long straight section.  The top nut can run down another 1/4 inch once everything is in place.  I don't think that is an issue.