Umbrella seal usage
Thread Starter
Intermediate
Joined: Aug 2014
Posts: 45
Likes: 0
From: Southern NH
Umbrella seal usage
Hello Everyone!
I'm currently freshening up my 4K mile GM Goodwrench 350 crate motor with a new cam, lifters, and springs. My Mexican heads aren't machined for any kind of valve stem seal, the valve guide bosses are approximately .760" dia. OEM style o-ring seals were supplied with my cam kit but I also had bought umbrella seals thinking I could use them with this motor. I'm using the o-rings but was wondering if there would be any advantage or disadvantage to sliding on the umbrella seals down to the guide bosses and using them along with the o-ring seals as long as they don't interfere with the retainers when on full valve lift?
Thanks
I'm currently freshening up my 4K mile GM Goodwrench 350 crate motor with a new cam, lifters, and springs. My Mexican heads aren't machined for any kind of valve stem seal, the valve guide bosses are approximately .760" dia. OEM style o-ring seals were supplied with my cam kit but I also had bought umbrella seals thinking I could use them with this motor. I'm using the o-rings but was wondering if there would be any advantage or disadvantage to sliding on the umbrella seals down to the guide bosses and using them along with the o-ring seals as long as they don't interfere with the retainers when on full valve lift?
Thanks
Race Director
Joined: Apr 2009
Posts: 19,294
Likes: 2,753
From: Charlotte NC
I personally prefer to NOT 're-invent the wheel' in areas like this. If the heads are not machined for umbrella seals...and they were not installed..I do not put them in. And if you were not having an issue before with the seals being bad and smoking when your start it up....why do something that is not needed....and for what it is worth.....why aren't you calling GM Performance and talking with their tech line and ask them.
DUB
DUB
Le Mans Master
Joined: Oct 2007
Posts: 7,442
Likes: 967
From: Tennessee/Rhode Island
I agree with DUB HOWEVER, I changed my valve stem seals on my OEM L-82 in the mid 90's and did add umbrella seals to each valve as well since the umbrella seals are dirt cheap, I was already in there, and figured can't hurt (may not help either). Never had any issues.
Le Mans Master
Joined: Oct 2010
Posts: 6,922
Likes: 839
From: melbourne florida
2023 C3 of the Year Finalist - Modified
you won't hurt anything by using them they control oil better, however the o ring seal allows more oil on the valve and helps cooling a little, you decide which is more important.
Thread Starter
Intermediate
Joined: Aug 2014
Posts: 45
Likes: 0
From: Southern NH
There's actually not enough room to use the umbrella seals, I measured the length from the bottom of the retainer to the top of the seals and it would crush by .200" at max valve lift, so I'll just use the stock o-ring seals.
Race Director
Joined: Apr 2009
Posts: 19,294
Likes: 2,753
From: Charlotte NC
DUB
