85 headgaskets

[garrett]

I have a new set of 1985 turbo headgaskets. They are steel with some sort of coating on them. They are made by Fel-pro 8723 I think. I usually use RJC steel headgaskets with the adhesive. These Felpros are clearly not the same embossed type of gaskets, but I wonder if they could be used with the adhesive as well. I know the deck height is also different on a 109 block vs a hotair 85 block. If I were to used these 85 geadgaskets on a 109 block, how would that affect the compression ratio? Any ideas?

 

[Lee Thompson]

Not an exact answer but

Factory 85 steel shim gaskets are .018 thick, compressed.
86-87 factory gaskets are .060 compressed.

 

[garrett]

raised compression ratio

So this would definately raise the compression ratio alittle. How would .042 afect the engine?

 

[sweetv6]

some info i found on buick board

Head milled vs compression


Head milled .025-.030" (43cc) w/stock .060" = 8.55 cr
" " " " " 1000 Fel Pro .0375" = 8.86 cr
" " " " " 2 steel shim .036" = 8.95 cr
" " " " " 1 steel shim .018" = 9.31 cr

Stock (48cc) with stock gasket .060" = 8.122cr
Stock " with P/N 1000 Fel Pro .0375" = 8.40 cr
Stock " with 2 steel shim .036" = 8.48 cr
Stock " with 1 steel shim .018" = 8.79 cr

hope it help

Claude

 

[garrett]

compression ratio

So my compression ratio would be about 8.6 to 1. I guess that would be OK.

 

[garrett]

headgasket

After talking with someone from RJC racing, they said that they used to use the 85 steel headgaskets with their sealer. They actually used to use two sets/ double thick. Now they use the stainless steel headgaskets with the sealer.
I will probably use the 85 gaskets on the hotair block I will have rebuilt and their stainless steel gaskets on the 109 block I have. I will slather both of them with the sealant and clamp them down with ARP studs.