Can someone PLEASE explain the process for me? I would like to try this and need help figuring out how exactly it is done. When measuring with a shim in place, do you include the shim with the total measurement, or just from the bottom of the spring to the top?

 

Well your going to need a few tools like a compression tester, a valve spring compressor tool, an assortment of spring shims and I highly suggest getting a valve spring micrometer. You'll also need an air compressor for the compression tester.

The steps really are quite simple.
1. Screw the hose from the compression tester into the spark plug hole of the cylinder where you're going to be replacing the valve spring and put some pressure to the cylinder. It doesn't take that much air pressure. Maybe 50 psi or so. Obviously the pressure is there to prevent the valve from dropping into the cylinder while your doing your work. If you hear a rush of air when compressing the spring then either up the air pressure or tap the valve gently in order to loosen it up.

2. Remove the rocker arm and use the valve spring compressor tool to remove the valve spring and any spring shims that might be in place. I usually place a short piece of vacuum hose over the rocker stud to protect the rocker stud threads and also to keep from getting small shards of metal all over the place.

3. After the spring is removed place the valve spring micrometer back over the valve stem, reinstall the retainer, and screw the spring micrometer out until it is firmly seated against the srping pocket and the retainer. WRITE DOWN THE MEASUREMENT. Here's a tip. Always position the spring micrometer so that you can read it easily. I use a magnifying glass just to read the mic because my vision sucks.

4. Using a calculator subtract the installed height of your springs from the available height (the measurement you took) and that calculation will tell you what the total thickness of the shims will have to be. Or in other words: available height-installed spring height=total shim thickness.

When re-installing the springs remember it's nice to use a small magnet to help with the keepers. You'll probably have to consider different combinations of shims in order to get your installed height dialed in within a couple of thousands of an inch.

The process isn't really that big of a deal and if I can do anyone can.

Please, if I've listed any incorrect instructions, by all means, somone please correct me.

 

The installed spring height is just the spring. From the top of the shim or valve pocket to the underside of the spring retainer.

If you look on the spring pages on the Comp Cams web site you can see in the tables that you can vary the installed height to get the required spring pressure for both closed and open.

 

Thanks guys. I'm gonna have to run over and get a valve spring micrometer. It doesn't sound to difficult to do. Do I have to measure every valve spring, or just one?

 

What are you doing and why? Do to variations in the valve pocket depth different valves might have various amounts of shim thickness. So yes, you need to check every one.

A side note: For your typical h-flat low lift cam with a stock red line. Close is good enough. Like who cares. But if you are running close tolarances and try ing to get every ounce of hp and coil bind/valve float scare you in the case of sollid or roller cams. Then check everything

 

You shouldn't assume that the distance from the valve spring pocket to the bottom of the retainer will be the same for every valve. There will be some variance so yes, measure them all.

Remember, write all of your measurements and calculations down for every valve and proceed methodically and carefully. Like you said, it isn't that difficult.

Let us know how it goes.

 

What type of valve springs are you wanting to install, and why?

If you are going to all the trouble to change springs I would highly recommend the Beehives from Comp-Cams

 

I'm going to try to install some summit racing valve springs that I have laying around. I was going to use these for the Camaro, but decided to add a cam on the Vette and use the springs I already have. The Camaro will just have to wait a bit. It's a hydraulic flat tappet cam, for now.

 

i would not just throw a set of ??? springs in.... they need to match you cam and heads.....

are you using these springs with the stock cam?

A stock cam does not need duel springs.....

there is a lot more to it than just getting the correct hight (which is spring only hight after install)

then what are you specs on the spring? what is its coil bind hight? what seat size? correct keepers and retainers for the spring and heads? and a lot more

 

I contacted a summit tech person and he recommended a cam that would match the springs and what I have in the car. Hopefully all goes well.

 

you said you have had these springs for some time.... how long? technology has changed drastically in the past several years on valve springs..

What cam did they recommend? What HP are you trying to achieve? What other engine mods have you done or plan to do?

 

I've only had these springs for about a month and a half. This is the cam they recommended: http://www.summitracing.com/parts/SUM-K00112/
I'm going to be installing Hooker side mounted exhaust, Performer RPM intake, new ignition system, and a Holley carb, not sure which one yet.

 

ok... i see several things I think are wrong here.....

first of all that cam does not match the manifold you have chosen, it is says it works from 3500-7000.... the RPM manifold is for 1500-6500......
also, are you really going to rev that engine to 7K? better have it balanced along with the flywheel. the carb would have to be like a 750....

I think you are going about this in the wrong manner.... dont look for a cam that fits your springs, look for a cam that would fit your engine and driving...... 3500 ????? would you have any bottom end to get around town?........ Also I would tell you to NEVER get a flat tappet cam...NEVER!!! 600 miles I got on one before it went really flat!! ruined the whole engine... roller gives more HP and last longer, and does not need to be broke in, and you can run what ever oil floats your boat....save a little now, spend a lot later....


sale the springs on flee-bay, buy yourself the cam and lifters you need.... and springs... my recommendations are the Comp-Cams Beehives....for cam, Edelbrock 2201 preformer RPM roller

Gkull is also very knowledgeable about this subject...

 

I see what you're saying. I'm going to have to think this over. Thanks.

 

You've gotten some good advice here, so you're making the right call to stop and think it over. The springs should be determined by the cam, not the other way 'round.

 

That's why I love this forum, it's full of people with lots of great knowledge and great information.