Valve Stem Seals

[Scott Marzahl]

I'm working on a set of "041" heads to use on the son's '76 rebuild. I just finished pocket porting them, and I'm lapping in the valves now, and the cast iron guides are serviceable. The inlet guides were once cut to .530" and had a PC type seal installed. The exhaust guides are still .563" and the exhaust side was only using the stock O ring. Both the intake and exhaust valves still had the spring covers installed.

I know there is some debate wether to use a PC seal on the exhaust or not because the exhaust could use the lubrication and heat transfer from the oil. However, the other thought is that there is enough vacumn generated that the exhaust should have a PC seal as well.

Then of course if both have PC seals installed, do you still use the O ring and or the spring covers.

Or do I just install a new PC seal on the intake and an O ring and umbrella on the exhaust since the guides aren't cut yet?

Thanks,
Scott

[Clem Z.]

Re: Valve Stem Seals

i would use the PC seals on the intake only and do not use the spring covers or the "O" rings and on the exhaust i would use a umbrella type seal and leave off the spring covers and "O" rings. using the spring covers and "O" rings with any other type seal will cut down too much on the lube to the valve stems