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General Category => General Discussion => Topic started by: Turin on January 08, 2022, 05:24:49 PM
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I'm having a set of big valve heads ported etc. We will be replacing the valve guides and I was asked about valve stem seals. Would these be a good addition or would adding them adding them cause the valve guides on a the already wear prone big valve motor to wear even more prematurely do to a lack of lubrication?
I've heard of stem seals on a loop. My application is a bit different as I am building a hot motor.
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My shop manual shows no stem seals, maybe because they run the clearance at about half of what "normal" is. My $.02
Paul B :boozing:
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Guzzi has them on the newer bigblocks, I don't think they harm anything.
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25 years ago I put a set of valve guide seals from an HD shovel head in my Le Mans 2 and 5 years later I put the
same set in a friends Le Mans 2 . Last year he got in touch to see where I got them from 'cuz he was doing a top
end refresh . They definitely reduce oil consumption and judging by how long it's been between their replacement, they
certainly don't increase the valve to guide clearance from wear :) . My Le Mans has had performance cams in it for
over 200,000 kms . I guess you could call me a fan of valve guide seals ! Peter
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I'm having a set of big valve heads ported etc. We will be replacing the valve guides and I was asked about valve stem seals. Would these be a good addition or would adding them adding them cause the valve guides on a the already wear prone big valve motor to wear even more prematurely do to a lack of lubrication?
I've heard of stem seals on a loop. My application is a bit different as I am building a hot motor.
To some extent it depends on what guide material you're going to use. The std Guzzi knife edge scraper arrangement is a bit naff I agree. Clearance of the seal to the valve spring collar is also a consideration at full lift plus some margin. I'm not sure how close the bottom of the collar run to the top of the guide in the std configuration and if you decided on seals whether you would need to shorten the guides to gain some clearance. Things to consider.
Ciao
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To some extent it depends on what guide material you're going to use. The std Guzzi knife edge scraper arrangement is a bit naff I agree. Clearance of the seal to the valve spring collar is also a consideration at full lift plus some margin. I'm not sure how close the bottom of the collar run to the top of the guide in the std configuration and if you decided on seals whether you would need to shorten the guides to gain some clearance. Things to consider.
Ciao
What he said
I learned the hard way, 20+ years ago, first clue I got was little springs in the sump
Then I think I finally got the ABC
Assume nothing
Believe no-one
Check EVERYTHING
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I had the guides K-Lined on my LM2, mainly due to not wanting to risk damaging the heads by hammering the old guides out but also because they are supposedly a better option? (longer life, tighter tolerances etc.)
I didn't fit any seals though because it never had them before and I assume this was for a reason - valve lubrication?
I don't do high mileages on this bike but I've not noticed any oil consumption between changes.
Anyway, seals or no seals it's worth looking at K-Lining.
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I had the guides K-Lined on my LM2, mainly due to not wanting to risk damaging the heads by hammering the old guides out but also because they are supposedly a better option? (longer life, tighter tolerances etc.)
I didn't fit any seals though because it never had them before and I assume this was for a reason - valve lubrication?
I don't do high mileages on this bike but I've not noticed any oil consumption between changes.
Anyway, seals or no seals it's worth looking at K-Lining.
Yes K-lines are good. I have a kit and did my Daytona guides. Here's an image of my kit. I made some of my own tooling/guides to keep the kit cost down.
(https://i.ibb.co/Srzy8bb/DSC00702.jpg) (https://ibb.co/Srzy8bb)
Ciao
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Already bought new guides. The idea of finding little springs in the sump sends chills down my spine.
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Already bought new guides. The idea of finding little springs in the sump sends chills down my spine.
I K-Lined brand new guides in a brand new head.
Ciao