I am trying to use a 1970/71 inner timing cover on my 1967 C25. With only a new camshaft and new camshaft bushes fitted to the crankcase half and timing cover the camshaft rotates freely until the cover screws are gently tightened at which point it locks up. I'm considering skimming the flange face of one of the bushes to create end float. Has anyone else dealt with this issue?
If I refit the original timing cover/bushes/camshaft, the camshaft does start to nip up but doesn't lock when the screws are tightened.
It's all about tolerances and the only way to adjust the end float is by skimming the shoulder on one of the bushes. Ideally, you should measure the separation between the bushes and the corresponding length of the camshaft and then adjust the separation to give you 3-5 thou of end float. Alternatively, skim the bush a small amount at a time until the camshaft just starts to rotate freely and then remove another few thou to give the required end float.
If it was me, I would do the measurements and then remove the bush to skim off the required amount (on my lathe).
Thanks Spaceman. Thats confirmed what I thought was necessary. I have measured the separation available, but I'm not convinced of the accuracy of my digital vernier. I think I'll just skim a few thou from a bush face and take it from there.
End float measurements are not that easy to do to the required accuracy and require a special attachment to a vernier calliper to allow it to be mounted precisely square to the direction of measurement - we are talking a small fraction of degree alignment accuracy required! Skimming off a few thou at a time works just as well but takes a bit more effort!