Shimmed valve spring long term test results.

[wistech]

Ive finnaly had a chance to inspect several of the engines that had the valves springs shimmed . All are over a year old. One head was staved for oil due to a resticted frame hose. Cams were shot but showed no damage from actual wear. Just heat. Valves springs were tested and still passed the same load test as when installed.
Head 2 was in a mx stroker engine for the last year. Cams looked like brand new. Valve clearances were perfect.
Head 3 was the orignal first shimmed head from 2 years ago. Cams still looked like the day were new. The cams are from Sandstorms original Cannibal . Well over 300 hours. That engine also went through a crank failure. The head was removed for replacement with a ported head with prototype camshafts.

I will post pics of those soon.

Most all valve springs can be shimmed with a .030" shim to bring them to above 40punds load test . I have only seen a select handfull on used or new valve springs ever pass a load test.
The cam bucket bores have been honed out on the younger heads but the older one was not but I suspect they have good clearance.

[cannondale27]

That is really good news.I also suspect even with varying hardness cams the little extra tension shim provides will stop any valve float and along with the VERY important bucket clearance Cams should last.Sure seems that way.The old saying "Keep it simple stupid" really has applied to alot of things motorwise.They were sooo close.

[wistech]

One thing also that must be noted is I have set the valve lash on all engines to 1/2 of the stock clearances with no side effects. This is said to help with cam "slap "wear .

[wistech]

After turning the moto's rev limiter up to 12,500 rpm I could not hear any valve float . I will be turning it back down to a more conservative limiter to help give it a chance at some durabilty though.