Quote:
Originally Posted by Holeshot71
What about the lobe next to it in the first pic. Does that show any evidence of wear?
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In that first photo I thought it was looking kind of tough also.
Just from that first photo, it was not a better 8620 cam core, it is obviously not a cast cam core either. Looks like a 5150 for 8660 cam core. My guess is a 5150, but I can’t tell those last two apart from the photo. The hard surfacing is not as thick on those cores…IRC, it would have to have pretty minor damage to be reground, it is a possibility though.
It could be the cam surface gave up over time, or it float the valves at some point and started to dig in to the ramp, it does have a good amount of lift. It could also be some needles in the roller bearing are gulled and dragging hard under a load. I suppose it could have even got some contaminates in the oil and cause that too, kind of unlikely though.
Only way to eliminate the lifter as the cause is to press the axle out and look over the needles.
That’s a bummer, at least it sounds like you had a lot of fun with it.