PSI for Valve Stem Seal Replacement?
Pro
Joined: Jul 2000
Posts: 654
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From: Now Frozen in Michigan
Re: PSI for Valve Stem Seal Replacement? (paul79)
Paul-
In theory, anything above atmospheric pressure would work. But I would set it at min 55 psi. I used 60 psi last time I did this. Good Luck -Rod :chevy
In theory, anything above atmospheric pressure would work. But I would set it at min 55 psi. I used 60 psi last time I did this. Good Luck -Rod :chevy
Melting Slicks
Joined: Dec 2000
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From: Union Ontario
Re: PSI for Valve Stem Seal Replacement? (paul79)
I regulated to around 90 PSI when I did mine but Max it out if you want, your engines dynamic pressures are way higher than your compressor can achieve so you'll never damage your engine with putting the pressure too high.
[Modified by MikeC, 10:33 AM 3/11/2002]
[Modified by MikeC, 10:33 AM 3/11/2002]
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Re: PSI for Valve Stem Seal Replacement? (paul79)
A helpful tip is to put the cylinder you're working on at TDC. In my engine you can't drop the valve all the way in that way.
Racer
Joined: Apr 2000
Posts: 499
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From: Kristiansand
Re: PSI for Valve Stem Seal Replacement? (paul79)
Paul: As others have said it takes very little pressure to hold the valves.
The problem is that the old, brittle o-rings wont allow you to compress the spring without opening the valve and creating a leak. Solution is to place a pipe-socket on the spring spacer and hit it with a hammer. This will brake the o-ring into small pieces and the valve can be compressed easily.
I have some stuff on valve adjustment at my page.
The problem is that the old, brittle o-rings wont allow you to compress the spring without opening the valve and creating a leak. Solution is to place a pipe-socket on the spring spacer and hit it with a hammer. This will brake the o-ring into small pieces and the valve can be compressed easily.
I have some stuff on valve adjustment at my page.
Burning Brakes
Joined: Dec 2000
Posts: 1,183
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From: Des Moines Iowa
Re: PSI for Valve Stem Seal Replacement? (Cam Potter)
This is a very good suggestion and I strongly recommend use of a water filter on your air compressor when performing this job.
ps... if your car is an automatic, then don't bother trying to place piston at top of stroke when you work on that particular cylinder, because once you put the air to it, the air pressure will force the piston to the bottom of it's stroke.
Use 90 lbs, and hit the edge of each valve spring with a hammer before you attempt to remove the valve locks, this will jar the valve cap loose, and make the removal process much easier.
ps... if your car is an automatic, then don't bother trying to place piston at top of stroke when you work on that particular cylinder, because once you put the air to it, the air pressure will force the piston to the bottom of it's stroke.
Use 90 lbs, and hit the edge of each valve spring with a hammer before you attempt to remove the valve locks, this will jar the valve cap loose, and make the removal process much easier.
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Melting Slicks
Joined: Feb 2001
Posts: 3,330
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From: Europe , Luxembourg
Re: PSI for Valve Stem Seal Replacement? (paul79)
Hi
When I replaced the seals of my big block L71 heads, I had to bring some of the pistons to TDC to be able to release the valve keepers by pressing the valve onto the piston. The 90 PSI air pressure where not enough on all pistons.
I agree that the air pressure moves the piston back down if it's not held with the manual gearbox in gear.
The hammer trick to loosen the keepers did not work on my car.
Good luck
Gunther
When I replaced the seals of my big block L71 heads, I had to bring some of the pistons to TDC to be able to release the valve keepers by pressing the valve onto the piston. The 90 PSI air pressure where not enough on all pistons.
I agree that the air pressure moves the piston back down if it's not held with the manual gearbox in gear.
The hammer trick to loosen the keepers did not work on my car.
Good luck
Gunther
