Stem seals V guide seals SBC

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Tom68
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Stem seals V guide seals SBC

Post by Tom68 »

Not a big fan of guide seals since I've never had an obvious problem when I've run the std SBC stem seals (saves cutting the brittle iron for guide seals) with and without the oil shields.

Oil shields.jpg

Nonetheless I run guide seals where they are already installed, Teflon ones in race motors.

So I have some Dart Iron heads that wore out the Exh guides but didn't hurt the intakes.

I happen to have a set of exhaust valves with the stem seal groove for the square section oem style Orings.

What's our thoughts on running the Dart guide seals on the intakes as supplied and running the exhaust with just the Orings and no oil shields ??
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Last edited by Tom68 on Mon Jan 23, 2023 3:19 am, edited 1 time in total.
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Re: Stem seals V guide seals SBC

Post by In-Tech »

Hiya Tom,
https://enginetech.com/valve-stem-seals/
Use the double lip positive seal and get the right cutter if you don't have one, many choices too. They provide a small amount of oil to the guide on each motion. Those Teflon seals have been garbage forever unless you like un-metered oil down the guide that gets worse with heat. The silicone umbrella's work really well with a stock type rebuild and spring on a SBC, although since about the early 90's I just cut and pc double lip everything nowadays.
Heat is energy, energy is horsepower...but you gotta control the heat.
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Re: Stem seals V guide seals SBC

Post by In-Tech »

Always think $3 a minute for your work. From the time you pick it up, 'till the time you put it on the next bench.
Valve Job = $xx
Surface = $xx
Guide liners = $xx
Machine Valve guides =$xx
Valve seals =$xx

No need to put the minutes involved on the invoice. You might want a valve, guide and seal on your front counter to show you're not in the '60's :) I think you will find your repeat shops don't ask for an explanation after the first time, the general public burns your time and "have" to be charged more for the talk ;)

Don't forget the cleaning charge, always collect that up-front in case your estimate call means they never come back to pick it up. :lol:
Heat is energy, energy is horsepower...but you gotta control the heat.
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Tom68
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Re: Stem seals V guide seals SBC

Post by Tom68 »

Well she's gone out with no exhaust guide seals.

Also no retainer stem O-ring seal, the Crower +150 retainers and plus 50 locks don't work with O-rings so fitted the locks with a bit of silicon in the gap.

Nothing ventured, nothing gained.
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rebelyell
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Re: Stem seals V guide seals SBC

Post by rebelyell »

older ain't necessarily better --- look at how GM designed iron vortec heads' valve stem seals --- fluoroelastomer aka FKM aka viton --- they're long-lasting and seal well even when stem-guide clearance becomes larger. JMO, a real improvement over square o-rings and/or tin shields.
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Re: Stem seals V guide seals SBC

Post by Tom68 »

rebelyell wrote: Sat Jan 28, 2023 9:16 pm older ain't necessarily better --- look at how GM designed iron vortec heads' valve stem seals --- fluoroelastomer aka FKM aka viton --- they're long-lasting and seal well even when stem-guide clearance becomes larger. JMO, a real improvement over square o-rings and/or tin shields.
I know, but these are pressed in Bronze guides in Iron heads, if they were integral or pressed in iron guides I doubt there would have been a problem running guide seals. We'll see, it flogged the exh guides with seals, we'll see what happens this time.
Ignorance leads to confidence more often than knowledge does.
Nah, I'm not leaving myself out of the ignorant brigade....at times.
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