Question on valve seals

[Dukesie79]

I've done some research on the tailpipe smoke I've developed and I've found that the valve seals on all of my exhaust valves (at least on the passenger side; haven't check the driver side) have came loose and are riding up and down. I can tell that the exhaust seals look different than the intake ones. The intake look like the have a tiny metal spring around the tops of them, whereas the exhaust ones are just like a rubber umbrella seal. I've read that stock heads and valves don't require seals on the exhaust, and I know my heads are stock irons that have been mildly ported and have "oversized" valves. What I don't know is whether the exhaust guides have been modified for seals. How can I tell? If they are, why would someone use different seals from exhaust to intake? I want to replace all of the seals with Manley viton seals as I've heard good things on here about them and want to make sure I get the right ones.

I am also having an issue with using Cotton's valve spring removal tool. When I pressurize the cylinder at top dead center with compressed air and I compress the spring, the valve moves as normal. I can't get the valve to stay up in order to remove the keepers. Should the air pressure be enough to keep the valves up or should I pry down enough to let the valves stop against the piston and then get the keepers off?? Do I just need to stuff rope or vacuum hose in the spark plug hole and let the valves press on that?? I've tried anywhere from 20psi to 100psi with no success.

 

[Abomb]

Take the tool off, keep air on the cylinder and be careful not to hit the valve but give the top of the retainer a hit downward with a hammer. I believe some use a socket over the retainer, I never do. Try again with the tool. The spring should compress and the valve should stay up allowing you to remove the keepers. If the valve still moves with the spring you didn't get a good enough hit. Or maybe your air isn't high enough. Again be sure not to hit the top of the actual valve in any way with the hammer, just the retainer. A pretty decent crack with the hammer is required. A magnetic tool like the one that looks like a telescoping metal pencil with a magnet at the end and a little magnetic tray is invaluable when it comes to the keepers. HTH Also it should be obvious if your guides have been cut for seals. Post a pic here if you have questions.

 

[Dukesie79]

Ok so here is a pic with the spring and seal removed. Is this original or set up for other seals?

 

[Dukesie79]

I've measured the intake guide diameter at .530 and the exhaust at .600. Valves are .344 stem diameter. Both guides are machined flat at the top so other than the size difference they look the same. I've looked at summit for seals that are for .600 and don't see anything. What am I missing here?

I can take more pics if it helps. Thanks!

 

[Dukesie79]

Did some more measuring. The positive stop seal I pulled off of the intake valve is .500 ID. The umbrella seal I pulled off of the exhaust is .650. I measured the guide heights and they are roughly the same. Measured from the head surface, the intake is roughly .690 and the exhaust is roughly .705. I've only pulled the springs and seals from the #2 cylinder so far so that is all I have to go on.

I want to order the .5oo ID viton seals for the intake and the .530 ID vitons for the exhaust. Does anyone see any reason that this won't work? Thanks guys, I really need to get parts ordered so I can get her back on the road.

 

[charlief1]

If the intakes are at .500 and the exhaust are at .650 then the intakes have been cut for a SBC seal and the exhaust are the stock Buick seals. Trying to stretch a seal from .530 to .650 will be a pain and most likely will damage the seal so either cut the guides to .500 on both or get 1 set of SBC intakes and 1 set of Buicks for the exhaust.

 

[Dukesie79]

Well the guides themselves are .530 and .600 OD. The seals I have were .500 and .650 ID. But the intake was positive stop and the exhaust was umbrella. Guess that's where I'm confused on what I have and what to buy.