promotor wrote:That valve spring set-up looks to be an Iskenderian one - normally to give more room for higher lift cams with standard length valves and no machining to the valve seat pockets in the head.
I can't remember what the installed length of the valves should be but the shims / washers will be to set the spring at the right pre-load / height. Of the sets of Iskenderian springs I have seen they have all had washers like those with them.
You hope the shims had been used to set the spring heights and thus loads correctly by the engine builder but I have seen it done wrong to often to have any confidence without doing the detailed measurements and calculations myself. I don't even trust the spring suppliers installed height recommendations as these can be well outside the ballpark for some builds. I measure the spring rate and then determine the required installed height for the needed seat and cam nose loads for the engine use and with the cam its using paying due regard to all the other clearance issues that also need to be satisfied.
In general when building a high lift cam engine you are struggling to get enough space for the valve spring to be in the right operating load range and all the other clearances right. Adding shims under the spring seat unless you're compensating for spring pocket depth variation ( in which case the shallowest pocket should have no shim) can mean something else is not right as your using up space you should not have in the first place.
regards
Rohan