Wibäck

Hello

I am searching everywhere but cannot find any answer. I am changing the valve seals and thought that i would put seals over the guides of the intake valves to minimize oil leakage into the combustion chamber. The outer diameter of the guide is 0.578" (37/64"). What kind of seal would fit over that.

If I am missing some point here please point that out to me. This is the first time I disassemble an engine.

The engine is a stock 1975 l48.

Thanks
Fredrik

Jud Chapin

I used Fel-Pro umbrella type on my stock '76 and they're great.

gjohnson

I recently did my valve seals .Umbrella from Summit #slp-mv1598. While your in there I'd replace the o-ring seals also on both intake /exhaust

Wibäck

Yes, the o-rings broke apart like hard plastic so I will replace them. The problem I have is that I don't understand how to find an umbrella type seal that fits my valve guide (0.578"). Are they sort of rubbery so that one size fits all?

The MV1598 specs:
Valve Stem Diameter: 0.313 in.
Valve Stem Seal Type: Umbrella
Valve Stem Seal Material: Rubber
Machine Work Required: No
Valve Guide Diameter (in): 0.688 in.
Valve Stem Seal Outside Diameter (in): 0.755 in.

What does the Valve Guide Diameter mean in this case? Is that not what I have measured?

Thanks
Fredrik



The diameter I have measured (on intake valve)

jb78L-82

Most folks just replace the oring seal with an umbrella seal and its best to replace both-good insurance that no oil will seep past the Valve stem….

Jud Chapin

I don't know the auto parts situation in Sweden, but in the USA any quality auto parts store will carry these seals for your stock engine. You just need to provide them with your car and engine info. There is nothing special or unique about these seals.

oldchev

As indicated above, the common method here is to replace the o-ring style seal with the umbrella style. The umbrella style fits at the same location as the o-ring did. One size fits all. Years ago when I first had done this, the umbrella style was called the Ford type of seal. Evidently because at that time maybe Chevy didn't have any such thing. But today about every aftermarket supplier will supply an Unbrella type seal. But don't get confused by the later type seal that snaps on to the top of the valve guide. Gen 1 heads can't take that seal unless the top of the guides are machined for them. Dave.

gjohnson

Fredrik,
The umbrella slides down over the guide and fits snug on the valve "stem" not the guide. It moves with the valve. Those from Summit will fit .They do not replace the o-ring they are in addition to

70T4

I purchased a 74 this year that need valve seals and did the job a couple of months ago. My heads are 882 heads which are likely the same as yours. I used Fel-Pro part #SS10058 (umbrella seals) and Fel-Pro part #SS5112 (o-ring seals). These are available everywhere - Ebay, Amazon, Summit, etc.

Wibäck

Thank you guys for bearing with me!

The availability of parts in Sweden are good and there is always eBay so anything you suggest is easy for me to get.

So, installation
1. Slide on the umbrella seal and push it over the guide
2. Install spring, shield and retainer
3. Compress and install o-ring seal and keepers

Correct?

If the umbrella seals are snug to the stem, how would any lubrication reach the guide?

Fredrik

Jud Chapin

Hi again, Fredrik. If I may say so, I believe you are over thinking this. Just order the parts and they should come with detailed installation instructions. And of course it's always a good idea to have a GM manual on hand for your year Vette which will provide instructions for most things you want to repair on your car. Good luck.

Wibäck

Well I'm an engineer and I love being in control... I'll order a set from my local dealer and take it from there.

Thanks!
Fredrik

Jud Chapin

You da man! And, BTW, I've been to Sweden and it's a beautiful country.
Jud

gjohnson

They go up /down w/ the valve exposing the guide only covering it from above like an umbrella.......