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-   -   Chevy 235...valve stem seals? (http://www.hotrodders.com/forum/chevy-235-valve-stem-seals-43087.html)

Slickriffs 07-08-2004 12:03 PM

Chevy 235...valve stem seals?
 
I have a 55 Chevy truck that I have worked on, on and off, for 20 years. The 235 block is not original and was rebuilt by me 20 years ago...however I'd be surprized if there is even 10,000 on the block.

The head is from the original engine..It had a crack and was "stitched" (I believe thats the term) I'm not certain if I had any other head work done to this.

I'm visibly burning oil...and suspect the Valve stem seals. I haven't done a leak down test yet but I will. In the meantime I pulled the valve cover to look at the seals. I don't see anything rubber at all between the valve guide and the top of the spring..no groove with an O ring or umbrella...If I had them that's where they would be right? I have anothere head to rebuild(It's where I lived 7 years ago...it's still in the basement) but in the meantime..for education sake..am I missing something?

Thanks,

Keith

willys36@aol.com 07-08-2004 12:09 PM

those engines didn't have seals and only O-rings if anything. Yours are gone many moons if they were ever there. I just had my head rebuilt and don't remember what they put in there but for sure there were no seals.

Slickriffs 07-08-2004 12:32 PM

Humm..Thanks Willy's..

Then I guess the stem to guide clearance must be critical? I mean thats the only defense against sucking oil there then right?

I thought these were supposed to have the umbrella type seals...

Sounds like it time to investigate rebuilding the other head.

Thanks for guick response..much appreciated..

Keith

Slickriffs 07-13-2004 09:09 PM

Bump

tresi 07-13-2004 09:44 PM

Quote:

Originally posted by Slickriffs
Humm..Thanks Willy's..

Then I guess the stem to guide clearance must be critical? I mean thats the only defense against sucking oil there then right?

I thought these were supposed to have the umbrella type seals...

Sounds like it time to investigate rebuilding the other head.

Thanks for guick response..much appreciated..

Keith

While many people get the idea that the little O-ring is the only valve stem seal that's only 1/2 right. The metal cup between the spring and retainer is susposed to act like an umbrella. The O-ring is to keep oil running down the split between the locks. Many people add rubber umbrellas when they rebuild. Even if you did add the rubber umbrellas 20 years ago they are in the bottom of the pan by now. As with any rubber part time is as much of a factor as miles.

Slickriffs 07-14-2004 05:43 AM

Thanks for the post tresi..I've located a few diagrams from Chilton..This Chilton was for cars while mine is a truck..but they actually showed what appears to be a sheetmetal cap that fit over the top of the springs..at least on some models..yes I guess that certainly would act as an umbrella. My truck however only has a flat piece between the spring and keeper.

It sounds at best that these devices are marginal and it's really the stem - to -guide clearance that manages the oil. These valves etc could be 49 years old..so no surprize..I just wanted to get a fix on what the seals should look like.

I'll check the bottom of the oil pan...lol.

Appreciate the time you spent responding.

Keith


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