Which head gasket for the standard engine?

DRG-ler

DRG-ler

Senior Member
Hi folks... the head gasket between cylinders 3 and 4 on my Model A has blown. The old trouble. Now I would like to know which new head gasket I should use? There are copper seals, graphite seals with steel inserts or modern composite seals. What would you use for an untuned stock engine?

Then I would like to exchange the studs, because they no longer look appealing. But I would like to clean and recut the threads in the engine body. Can someone tell me which thread is in the block?

Oh and can someone tell me how much torque the head screws are tightened with? Dry or oiled?

I'll probably give the head to the engine builder again and have it planned if it's warped. Unfortunately I have to get the remains of the distributor out of my head now. As usual, it broke off. However, that was already an old break.


Greetings Andy
 
The threads in the block are 7/16 14tpi. The distributor remains can usually be tapped out of the head with a medium hammer.
 
I like the Best Graphtite 509G. I would stay away from the "Modern" gasket with the silicone around the water passages.
 
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I have had the best luck with the graphite gasket with the steel edges (inserts) and a coating of the spray copper gasket cement.

It is important to assure that you have a flat head and block. There should be no more than 0.002 inch gap anywhere. Also no pits or scratches. Minor imperfections can be filled with JB Weld and sanded flat with 400 grit wrapped around a flat file.

Clean the head and block well. I use a wipe of acetone at the last step.

It is also very important to torque correctly. Torque in 10 foot-pound increments to 55 foot-pounds and then warm up the engine and shut it down. Re torque the next day after the engine has cooled. Re torque again after 100 miles on a cold engine and then again after 500 miles on a cold engine. Re torque every 6 months, always on a cold engine.

Large increments of torque can crack the block or head. Use the 10 foot-pound increments.
 
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I like to back the head nuts off a 1/4 turn or so, one at a time, before retorquing then. I've found that it make's a difference on where the nut ends up. Am I the only one to do this?
 
I think that warming it up and then allowing it to cool overnight with coolant in the engine before torqueing again is an excellent way for coolant to seep in between the gasket and block/head. I would not do this.
 
Soft copper and asbestos or ceramic fiber still work very well if copper coated and properly torqued. The key is to get a gasket that has the proper bore size. I left a link to Vince's site on the other thread. It has a guide to head gaskets.

If you use the Electro-Lock cable clamp on the #8 stud between #3 & #4 cylinders. Be sure it's ready to torque. You don't want to take it loose after the nut is torqued. This may cause problems in a critical spot.
 
I've never used any type of sealer or coating on a head gasket and never had a problem in the last 65 or so years. Not just Model As, all kinds of engines, from small one lungers up through large diesels, The largest was a White-Superior 8 cylinder in-line w/11" pistons.
 
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