umbrellla style valve seals
Thread Starter
Burning Brakes
Joined: Aug 2000
Posts: 1,211
Likes: 6
umbrellla style valve seals
I noticed on my heads that the exhaust valve seals (umbrella style) appear to have moved up on the valve stem on some of the valves. Is this O.K.?
Other than umbrella style what other seals are being used? What type is the best to use? And why are the exhaust style different than the intake???
Any help appreciated!!!
Regards, Mark
:chevy :flag
Other than umbrella style what other seals are being used? What type is the best to use? And why are the exhaust style different than the intake???
Any help appreciated!!!
Regards, Mark
:chevy :flag
Le Mans Master
Joined: Sep 2000
Posts: 5,635
Likes: 4
From: Orlando Floriduh
Re: umbrellla style valve seals (marky mark)
I put a set on 71 that I had... I wondered the same thing.... I had one really bad valve guide and a couple of others that were worn. The umbrella seals did the job.. :confused:
Safety Car
Joined: Jun 2001
Posts: 4,004
Likes: 2
From: Severna Park Md
Re: umbrellla style valve seals (marky mark)
Umberlla seals are designed to ride with the stem. When you first put them on you push them down all the way. But the first time the valve opens the seal gets pushed up on the stem. From then on it rides on the stem in that location. Umbrella seals that are sitting down on the guide after being run are loose enough not to stick with the stem, and are worn and probably need reolacing.
Positive seals lock down over the guide and stay down. There could be, but theres not always a difference between seals for exhaust and intake valves. On my vette motor thier all the same since all the guides are the same. On my 350 SB in my truck thier different for exhaust and intake. The reason for the seal difference there is the exhaust valve guide were replaced with oned that were a different diameter. The valve stems are still the same so if I were running umbrella style seals they would still be the same for both exh and int. But since I run positive seals on that motor, they need different seals to account for the different diameter guides.
Positive seals lock down over the guide and stay down. There could be, but theres not always a difference between seals for exhaust and intake valves. On my vette motor thier all the same since all the guides are the same. On my 350 SB in my truck thier different for exhaust and intake. The reason for the seal difference there is the exhaust valve guide were replaced with oned that were a different diameter. The valve stems are still the same so if I were running umbrella style seals they would still be the same for both exh and int. But since I run positive seals on that motor, they need different seals to account for the different diameter guides.
Racer
Joined: Sep 2000
Posts: 355
Likes: 0
From: Valdosta Georgia
Re: umbrellla style valve seals (marky mark)
Mark, the other explanations are correct. I use a combination of seals. A local machine shop operator taught me to use the positive type seals that GM started using in the 80's, on the intake valves and to use the umbrella seals on the exhaust valves. I have built about six different sets of heads so far with this setup and no problems so far. Hershey :chevy :chevy
Thread Starter
Burning Brakes
Joined: Aug 2000
Posts: 1,211
Likes: 6
Re: umbrellla style valve seals (Hershey)
O K and thanks for the info. Some are sitting down and others are riding on the stem so I guess some are loose. I've read that some engine builders don't even use seals on the exhaust side.
Thanks again. Mark
Thanks again. Mark
