Some engines used a horseshoe shaped spacer between the cam sprocket and the cam face to space the sprocket to provide the correct amount of thrust clearance....others used a stepped cam sprocket which abutted the cam face to provide the thrust clearance..
Either can have material removed to tighten up the thrust clearance....as I said in my previous post, you can either remove the material in a lathe or by rubbing the part against some aluminum oxide cloth affixed to a surface plate or flat piece of steel. If you don't have a micrometer to measure what you're removing, do it a little at a time and track you progress with a dial indicator or feeler guage....You'll be removing over 1/32" of material so it may take a while by the sanding method...
I built my own needle thrust units and would recommend them only for racing or other severe duty application...they are expensive to buy, approaching 100.00, and must be installed precisely to work. The advantage is a bit less friction and the ability to run a restrictor in the feed passage which re-directs oil to more important functions...
Any other questions...? Post...
Pat
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