Valve spring seal/shim question
 

Can you guys give me some advice please.

I just shimmed my dual valvesprings on my mild small-block Ford 302 and noticed that the shims I used (.060-inch blue shims) slid over the outer edge of the valve seals fine but they are not resting completely under them. The inner diameter of the shim is higher than the lower portion of the metal strap that slides over the seal to hold it in place on the guide.

These are mild dual valvesprings with 160-lb of seat pressure and the engine never goes over 5800 rpm. I am just thinking that when the spring dances around some, the shim might want to move that strap on the white valve seals and possibly loosen it. What do you guys think? I find it hard to believe that it will really do anything but am just being paranoid. The spring cups have been over the seals for years and have never done anything but the shims just have me thinking.

Thank you,

Re: Valve spring seal/shim question
 

Another option would have been to use Comp Cams -0.050 Locks. I just did this on one of my motors rather than having to pull the seals to install shims.

Re: Valve spring seal/shim question
 

John,
Personally, I would not want anything hitting the seal, too much chance of it getting hurt. The spring cup might not have caused a aproblem if it is located on its od so it cannot move. If the shim is sized correctly and cannot move, it might be ok. I personally put the shims under the spring cup if at all possible.

Like Bill said, -.050 locks would be a better alternative.

Re: Valve spring seal/shim question
 

Thanks guys.

The lock idea sounds like the perfect plan. The shims are under the spring cups and there is no recessed groove for the cups to sit in on the base of the head. I figured that if the cups ran over the seals for years with no problems, the .060 shim wouldn't do anything but am still slightly concerned.