Sealing knuck heads..what to use?

[drs23]

I've got a set of '47 knuck heads the owner brought in because they were leaking under the spring cups. Upon disassembley I found the paper gaskets to be burned up thus no way are they going to seal. I'd thought about using Yamabond or 3Bond 1194 (which I think is the same thing). What do you guys use that won't burn up?

TIA.

Dale

[ridgerider]

the standard knuck gasket set has the (paper type gaskets) included... thats
what i used....the cups are held in place with the valve guides in a special washer, i would think putting goo under there would effect the height of the guide in relation to the head and valve seat ,rocker arms ect...hope that helps

[drs23]

Thanks,

That's what was done the last time these were assembled. Upon disassembley they were burned beond recongnition on the exhaust side and leaking badly. Was just wodering if anyone knew of a sealer that would stand up to the temp. Gonna give it a shot and see what happens.

Thanks for the reply,

Dale

[ricochet]

What I've done the last couple of times with no leaks is to use the stock paper gaskets and high heat silicone but to the earlier point about affecting installed height I concentrate the goop in a circle outboard of the gasket edge with a little on the gasket.  This causes the stuff to squeeze out.  I use black and wipe off excess making sure to have sealing all the way around.  Make sure heads and tins are real clean to get perfect adhesion.  Do make sure you have adequate interferance fit so guide doesn't work loose and press them in good to compress all.  Check your tins carefully.  I had 3 out of 4 with cracks right at the point where the guide outside dia edge pressed against the tins on the inside.  All three were not immediately apparent as the crack was real thin and in line with the wear from the guide compressing against it.  I ended up brazing them.  Could see the crack with light on the backside.

I use yamabond on the top covers.

ricochet