Flathead Head Gasket Question

I previously posted about the problem I was having with the pistons hitting the heads on the 59A flathead in my 32 Ford 5 window. The pistons clear the deck by about .025 at TDC and are just barely hitting the heads at TDC with the heads fully torqued to 50 ft/lbs and using ordinary copper head gaskets. The heads are Navarro heads from H&H. The pistons are domed Egge's. I'm guessing the builder used Ford pistons with the Mercury crank and that's what's causing the interference.

I called the guys at SCE gaskets and ordered a set of their solid copper gaskets to hopefully solve the problem without having to tear the engine apart. I ordered the .093 thickness gaskets because I was told I should have about .050 clearance between the head and the piston. The old regular gaskets crushed to about .038 to .040 so I figured the .093 gaskets would give me about the clearance I needed.

I got the gaskets from SCE and placed them on the block. Now it looks like I probably could have solved the interference problem with the next size down gasket, which I believe is .075.

My question is this: how much of a compression loss can I expect using the .093 rather than the .075 gaskets? Will there be a noticeable loss of compression? The block is relieved and the engine is bored and stroked 3/8 by 1/4. Thanks for any help you guys can give.

 

if you are just going to be driving this car ,that much tolerance will never be noticed.

 

I agree you will not notice any difference in performance.

 

I had the same problem with my Navarro heads on my 59AB with the Egge dome pistons. Had to go with a thicker copper gasket as well. I don't have my notes, but we figured the .075 - .080 gasket would crush at least .010 - .012. Even if it was 15 thou., you'd still have enough for the .050 piston clearance. Haven't run it yet, but it seems to have solved the problem. I never called H&H about it though. Good luck.

Z

 

Those gaskets from SCE won't compress. I would clay the heads using them and see exactly what you have. I don't think that they used Ford pistons. If so they will be coming up above the deck. I had to have the dome cut on the EGGE pistons in an engine to get clearance as I wanted to not use the thicker head gaskets. The problem with using them is that if you are halfway to somewhere and you need a head gasket you are up shit creek.

 

The pistons do clear the deck -- by about .025 at TDC. That's why I guessed the builder might have used Ford pistons with the Mercury crank. I've also been told though that Egge's quality control is not that great and that the wrist pin location needs to be checked before the engine is bolted together.

In any event, the problem is there and my only options are the thick solid copper gaskets or tear the engine down and start over. I'm willing to give the gaskets a try but I'm not going to be happy if the extra thickness is going to mean a serious or noticeable loss in performance. The car is not a race car but I don't want a slug either. In addition to the Navarro heads and the bored and stroked motor, the engine is running a Potvin Super 3/4 cam and an Offenhauser regular dual manifold with Tardel risers and two 97's.

 

I would tear it down and mike the piston to see if it is Ford and if it is I would buy a set of Merc pistons and be done with it. If this is the problem your builder should be on the hook for repairs.

 

If you ask the same question enough times you will eventually get the answer you are looking for.

 

The dome sticks up above the deck not the crown edge...correct? I am having the same problem but it has to be a merc piston. I checked part #s over and over again. The part # etched on top of the piston is L-991-100. The Egge web page says 4'' stroke .100 oversize. The Edelbrock heads are new and they hit. I know the deck has been cut but I don't know how much. Definatly not enough to have this problem.

 

I'd have to say that Mr. Egge has a problem that needs fixing at the Egge Machine Shop, NOT in YOUR garage at home or at the rebuilder's shop. The least they should do is provide NEW correctly made pistons to anyone having this problem, but to be fair they should eat the cost of tearing down these engines and reassembling them AND fire a couple or six machinists, what say?

From the other perspective, could the heads be modified to clear the pistons and still use the stock easily found head gaskets?

 

Did either of you call Egge to get their take on the pistons?

 

I had egge change their dome on the pistons because it hit every head. It was a continual problem. Now they finally have the same dome as Ross Pistons which never hit. Since the change I have not had to dome heads as much.
Mike
H&H Flatheads

 

You mean that no one checks the head piston clearance before buttoning up the engine? Or valve clearance?

traderjack

 

Put the head on without a gasket and see if it moves when you crank the engine,. that will give you a clue, not bolted down , of course. LOL


traderjack