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I am about to replace the valve seals on my '76. I have read previous discussions in the archive and received information from a trusted mechanic. I want to use "umbrella" seals. My question is "Do I also use the O-rings with the umbrella seals or do I skip the O-rings" ?
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Re: SB Valve Seals, 1 or 2 ???
No, you don't need the OE stem O-rings if you use another type of seal.
Why umbrella seals? It's not clear to me what they offer. The OE seals actually work quite well considering how simple and crude they are - as long as the guide clearance is not exessive.
Have you considered a "positive" type seal - the type that grips the top of the valve guide with a positive seal around the stem wrapped with a little spring - similar in design to typical shaft seals. These seals allow a controlled oil flow and are fairly tolerant of excess stem-guide clearance.
Once you have the valve springs off check the guide clearance. A few years ago when I decided to change the guide seals on my Cosworth Vega, once the springs were off and I realized that the guides were severely worn it was "off with the head" for new guides.
Duke -
Re: SB Valve Seals, 1 or 2 ???
No, you don't need the OE stem O-rings if you use another type of seal.
Why umbrella seals? It's not clear to me what they offer. The OE seals actually work quite well considering how simple and crude they are - as long as the guide clearance is not exessive.
Have you considered a "positive" type seal - the type that grips the top of the valve guide with a positive seal around the stem wrapped with a little spring - similar in design to typical shaft seals. These seals allow a controlled oil flow and are fairly tolerant of excess stem-guide clearance.
Once you have the valve springs off check the guide clearance. A few years ago when I decided to change the guide seals on my Cosworth Vega, once the springs were off and I realized that the guides were severely worn it was "off with the head" for new guides.
DukeComment
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Re: SB Valve Seals, 1 or 2 ???
If you decide to use the umbrella seals, check very closely for adequate clearance for the thickness of the seal at it's top. Some designs do not leave adequate clearance, and the result is pulled studs or worse! As Duke recommends, good Guides and stock seals work quite well.Bill Clupper #618Comment
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Re: SB Valve Seals, 1 or 2 ???
If you decide to use the umbrella seals, check very closely for adequate clearance for the thickness of the seal at it's top. Some designs do not leave adequate clearance, and the result is pulled studs or worse! As Duke recommends, good Guides and stock seals work quite well.Bill Clupper #618Comment
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one problem you will see if you do not have
edge orifice lifters is you will have about 20% more oil upstairs using piddle valve lifters that you have to control. if you had the valve guides rebushed make sure they did not use spiral wound material as this will have a direct path into the port and you will need a positive type seal on the intakesComment
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one problem you will see if you do not have
edge orifice lifters is you will have about 20% more oil upstairs using piddle valve lifters that you have to control. if you had the valve guides rebushed make sure they did not use spiral wound material as this will have a direct path into the port and you will need a positive type seal on the intakesComment
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