what size shims should I order for comp cams 980 ?

[Yah's 87]

this is a daily driver and has stock internals. Ive done valve springs before on a diesel engine. With the same spring actually. Anyway , I dont know the height that is best, nor the shim sizes to order, thankx!!!!!

 

[Chuck Leeper]

W/o a spring tester, and a hite mic, there's no way to know what, if any, shims may be needed.
AIRC, 1.700" is the factory installed hgt.

 

[ITSAV6]

X2 Without the tools and measuring it's a shot in the dark.

 

[Yah's 87]

the best info Ive learn so far is if removing the dampeners is to use a .40 for them . and it seems as if some have just straight up installed the new springs with the dampener.

 

[HackersDna]

Going to try and help ya, if nothing else understand why & what Chuck and ITSAV6 is saying. If you look at your cam card it will tell you what springs you should be using. The springs also come with information that you need to follow. Shims come into effect when "Installed height" is being adjusted. If its not correct you can either wipe out a cam lobe due to them putting too much pressure on the lobes constantly and can more than triple when open height is reached.. It can get way more complicated. Im just trying to give the 3rd grade description.

These are a set of GN1's I was doing tonight. The required installed height is 1.750. One of the tools the guys were talking about is in the pic. As you can see Im at 1.808. This is where shims come into play. "BTW there are many ways to get there. Some guys refuse to use shims" I thought I got a pic of the after... But by using a combination of shims under the locator I was able to get it in spec. It rarely gets perfect using shims but there is a percentage that is acceptable.

After that you have to have some sort of way to check installed pressure and open pressure. Ive enclosed some pics of different height checkers and what I use to check the pressures.

I hope this helps. If nothing else you need to know you could do instant damage to the valve train and cam if you just throw shims at any set of heads. They are never the same valve to valve. I don't recommend buying all this if your just trying to get through this project. Leave it to someone who has the knowledge and tools.

 

[earlbrown]

It depends on what poundage you want. And the only way to know what the poundage will be is with a spring tester. (and you have to guess at where it'll be after the springs 'take a set').

Now the bad part is you'll be damn lucky to learn what poundage the cam and valvetrain need to have. Then to add to the fun, spring rate is the factor that tells what it'll be whatever the valve is at full lift.

Getting that info from a cam 'tech' is damn near impossible and if you do get one to give a set of numbers, you'll most likely have the feeling that made up some shit to get you off the phone. (Everybody I've talked to at Comp Cams for example)

 

[SS/GN]

Here is a tool that works if you don't do this job often. It takes more time but stores easily in my tool box and was not expensive.

https://www.summitracing.com/int/parts/pro-66835/overview/