Headgasket Question??

[Anonymous]

Somthing I've noticed but don't understand....It's probably quite obvious to everyone but me....

Why is it that if I go to my local Car Quest/Pep Boys/Napa, etc I can ask for a headgasket set (composite type) and it will say that it fits a 144ci-250ci engine but the steel shim headgaskets are divided into a 144-170ci and 200-250ci grouping and they wont interchange??

I know the bores are different but how does the aftermarket get away with it?? Or does it have somthing to do with the sealing surface??

Thanks,

Doug

 

[63comet]

Heh Doug, I bought a kit off of e-bay and it said on the end that it fits 144,170,200,250. when I got the kit it had a steel shim head gasket, but when I laid it down on the deck of the 250, it looks like I am going to have to be careful or it will overlap the bores. Not sure I'm going to be using this one, I believe it is for 144, 170.

 

[Anonymous]

Hi, Doug;

After all my playing with these head gaskets, one thing is apparent: unless you use special pistons or deck the block more than .060", the head gasket's metal trim in the bore will never touch the piston. In mine, overbored .040" and no block deck, there is almost .080" clearance back from the bore to the metal ring all the way around on the Victor - even more on the Fel-Pro. The Ford gaskets ("C" series composites) are sized to accommodate the .060" max bore, when they spread to exactly that size when torqued to 70 ft-lbs.

I calc'd in this extra volume when I did my CR after disassembly with the Victor and found the following results:

.040" overbore + .005" head mill on 1979 300 CID = 7.8:1 CR.

Miserable, huh? It really runs it, too.

I've got some of the composite ones left, but still searching until the last minute for a steel one. I'm gonna port the thing and install the Clifford divider this next time around...

 

[Anonymous]

Okay....I think I understand now

The sealing ring sets back from the bore a little bit on the 200's and 250's but sets back a lot from the bore on the 170's and 144's...All the while decreascing the compression ratio and performance even more....

I saw somthing worth checking out on ebay.....A vintage Fel-Pro steel shim headgasket for a 170. I wonder if they ever made one for a 200??

I've seen old Fel-Pro parts catalogs on ebay before....The next one I see is MINE so I can check this out....

Later,

Doug