Changing Valve Springs
Thread Starter
Racer
Joined: May 2006
Posts: 423
Likes: 3
From: New Port Richey, FL
Changing Valve Springs
I was going to adjust the valves on my 383 and realized that there were single springs on the motor. Found a box in the garage and it had 16 smaller springs in it. I broke the cam in with the single springs and forgot to install the inner springs! Engine has about 100 hrs. on it since new. My question is- how do I install the inner springs? It's obvious that I have to remove the retainers to do it but how hard of a job is it with the heads on the car? I don't want to remove them. Do I buy some hose that will screw into the spark plug hole and pressurize it with a compressor? Do I have to use one of those crowbar tools on the rocker stud to compress the spring? Has anybody ever done this, and how hard was it? Thanx
Tech Contributor
Joined: Aug 1999
Posts: 14,375
Likes: 6,375
From: At my Bar drinking and wrenching in Lafayette Colorado
I was going to adjust the valves on my 383 and realized that there were single springs on the motor. Found a box in the garage and it had 16 smaller springs in it. I broke the cam in with the single springs and forgot to install the inner springs! Engine has about 100 hrs. on it since new. My question is- how do I install the inner springs? It's obvious that I have to remove the retainers to do it but how hard of a job is it with the heads on the car? I don't want to remove them. Do I buy some hose that will screw into the spark plug hole and pressurize it with a compressor? Do I have to use one of those crowbar tools on the rocker stud to compress the spring? Has anybody ever done this, and how hard was it? Thanx
http://www.summitracing.com/parts/sum-906784/overview/
and buy a cylinder pressurization hose like this:
http://www.summitracing.com/parts/wmr-w84003/overview/
Put a little pressure in the cylinder (the engine will rotate to BDC when you do, so watch that fan blade..!) and pop the retainers off, one at a time. You can do the entire job in less than an hour, even with a couple of beers.
Lars
Race Director
Joined: Nov 2002
Posts: 12,142
Likes: 54
From: Taylor Michigan
It's quick and easy to do. Just buy a valve spring compressor like this:
http://www.summitracing.com/parts/sum-906784/overview/
and buy a cylinder pressurization hose like this:
http://www.summitracing.com/parts/wmr-w84003/overview/
Put a little pressure in the cylinder (the engine will rotate to BDC when you do, so watch that fan blade..!) and pop the retainers off, one at a time. You can do the entire job in less than an hour, even with a couple of beers.
Lars
http://www.summitracing.com/parts/sum-906784/overview/
and buy a cylinder pressurization hose like this:
http://www.summitracing.com/parts/wmr-w84003/overview/
Put a little pressure in the cylinder (the engine will rotate to BDC when you do, so watch that fan blade..!) and pop the retainers off, one at a time. You can do the entire job in less than an hour, even with a couple of beers.
Lars
.......all that's missing is the beer.........
Safety Car
Joined: Nov 2008
Posts: 4,368
Likes: 9
From: Colorado
It's quick and easy to do. Just buy a valve spring compressor like this:
http://www.summitracing.com/parts/sum-906784/overview/
and buy a cylinder pressurization hose like this:
http://www.summitracing.com/parts/wmr-w84003/overview/
Put a little pressure in the cylinder (the engine will rotate to BDC when you do, so watch that fan blade..!) and pop the retainers off, one at a time. You can do the entire job in less than an hour, even with a couple of beers.
Lars
http://www.summitracing.com/parts/sum-906784/overview/
and buy a cylinder pressurization hose like this:
http://www.summitracing.com/parts/wmr-w84003/overview/
Put a little pressure in the cylinder (the engine will rotate to BDC when you do, so watch that fan blade..!) and pop the retainers off, one at a time. You can do the entire job in less than an hour, even with a couple of beers.
Lars
Safety Car
Joined: Mar 2007
Posts: 3,652
Likes: 49
From: Bridgewater nj
Make sure you bring the piston up on the cylinder you're working on. If you drop a valve, you'll be pulling a head but if your motor is running fine at high rpm, I would leave it. You're just increasing the potential of wiping a cam lobe with more pressure. IMO
Tech Contributor
Joined: Aug 1999
Posts: 14,375
Likes: 6,375
From: At my Bar drinking and wrenching in Lafayette Colorado
That won't work with the air pressure system. Once you remove the rocker arms, the valves will be closed. When pressure is applied, the air will force the piston down to bottom dead center. If you have it at the top of the stroke, the engine simply rotates 180 degrees in a real hurry... keep fingers and hands clear...
Another tip: Often, the keeper/retainer system will be a little "sticky", and will not break loose when you pull the valve spring compressor over. If this happens, you'll open the valve and loose air pressure. If you feel that the retainer is not going to break loose, give it a few taps with a rubber mallet as you pull on the compressor handle. This will knock it loose to prevent the valve from opening.
Lars
Another tip: Often, the keeper/retainer system will be a little "sticky", and will not break loose when you pull the valve spring compressor over. If this happens, you'll open the valve and loose air pressure. If you feel that the retainer is not going to break loose, give it a few taps with a rubber mallet as you pull on the compressor handle. This will knock it loose to prevent the valve from opening.
Lars
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Safety Car
Joined: Mar 2007
Posts: 3,652
Likes: 49
From: Bridgewater nj
That won't work with the air pressure system. Once you remove the rocker arms, the valves will be closed. When pressure is applied, the air will force the piston down to bottom dead center. If you have it at the top of the stroke, the engine simply rotates 180 degrees in a real hurry... keep fingers and hands clear...
Another tip: Often, the keeper/retainer system will be a little "sticky", and will not break loose when you pull the valve spring compressor over. If this happens, you'll open the valve and loose air pressure. If you feel that the retainer is not going to break loose, give it a few taps with a rubber mallet as you pull on the compressor handle. This will knock it loose to prevent the valve from opening.
Lars
Another tip: Often, the keeper/retainer system will be a little "sticky", and will not break loose when you pull the valve spring compressor over. If this happens, you'll open the valve and loose air pressure. If you feel that the retainer is not going to break loose, give it a few taps with a rubber mallet as you pull on the compressor handle. This will knock it loose to prevent the valve from opening.
Lars
Accidentally break that pressure seal or pop an air line and you just added 4 hours of labor. But hey, everyone has their thing but don't knock them for it
Tech Contributor
Joined: Aug 1999
Posts: 14,375
Likes: 6,375
From: At my Bar drinking and wrenching in Lafayette Colorado
If you're putting 30 psi in a 4-inch bore 350 (that's 30 psi applied over an area of 12.56 square inches), you're putting 377 pounds of force on top of your piston. If your engine doesn't spin over with 377 pounds of force on the piston, whether it's at TDC or not, you have a problem... I've been doing this for 40 years, and I've never even heard of someone dropping a valve using the method. (I run 20 psi when doing this, and that 20 psi will spin a TDC piston over very quickly, so I keep hands and fingers clear. I pull all 8 spark plugs out when doing this, so maybe you're temporarily locked against compression pressure. I don't trust compression pressure on a companion cylinder as an anti-rotation device.)
Lars
Lars
Last edited by lars; Aug 27, 2014 at 11:02 PM.