i figured id assemble the valvetrain on my lunch break today and discovered that the new seals that came with my rebuild kit do not fit snugly over the guide. they do seal snugly on the valve stem though. are there different kinds of seals available for these heads? i kept the old seals when i disassembled the heads and they fit well. However, they are very old and i do not want to install them. Neither of the part numbers on the seals cross reference to anything on a google search. i do not know if the guides on these heads are oem or not. it appears they were ported and had a valve job done when this motor was built 30+ years ago. so i do not know what has been replaced. it also had dual valve springs on it. i was hoping to put the heads on and finish assembling the engine tonight and just hit a major snag. any help would be appreciated. Thanks.
i just looked at the guides and they are bronze lined cast iron. is that oem or aftermarket? also with a caliper it appears that they are .500" OD. what size seals should i order? does there need to be an interference fit or will .500" ID seals work?
just in case anyone is interested. i found out that buick 300 guides are .520" OD. mine are .500" so i ordered a set of viton seals for a sbc 11/32" x .500"
Only the 64 300 aluminum heads had guides, 65 to 67 ran in cast iron, so yes, if they bronze they are after market. Valve stem seals are often referred to as "umbrella seals", I'm not sure if it is necessary for them to fit snugly on the outer diameter of the guides. BTW, they come from the factory with no seals, and if i were going to add seals I would only do the intake valves.
Hey Phil, Thanks for the clarification. This engine is a frankenstein of sorts. Its a sleeved 215 that has been bored and stroked to a 301. From everything i have gathered it was built by phil baker and has all sorts of his trickery in it. it has been very interesting trying to reverse engineer all of his work being a total noob to buick engines and their part interchangeability. But im almost there. The heads are the aluminum 64 heads with inserted guides. the guides are cast iron, but it appears they have had bronze liners installed in them. It appears the umbrella seals were ditched for a flex body positive seal, and the guides were turned down to .500" to accommodate them. I was under the impression that bronze guides can use positive seals on both intake and exhaust because of their self lubricating properties. i typically use torco assembly lube on the valve stems during assembly as well. i would hate to leave the exhaust seals off and get bad smoking on startup and carbon buildup on the valves. but im willing to listen to your advise if you think its the right way to go.
Exhaust valves need all the lubrication and cooling they can get. With that said, aren't some bronze guides are spiral, and if so, may need seals, I dunno. That's a pretty exotic engine, Derek does builds like that too, maybe he can help.
