Glad I changed camshafts

[68-500]

I was looking at the pics of your lifters before resurfacing. It appears that at least 1 had the wear pattern clear to the edge. That would clearly be scraping the oil off the cam. Maybe you have a loose lifter bore, allowing the lifter to tilt in the bore or a bore that was machined wrong?

 

[threewood]

Looks like a hole in the centre. The finish looks a bit rough to me, but it could be the pic. If you can catch your finger nail on the machining, that is a no-no.

EDM holes. It's an oiling feature. Lifter faces do not catch a nail.

 

[threewood]

If the OP has any way of doing so, I’d love to know what the lobe taper is on one of the lobes that has the really thin contact line that’s running off the edge, on the base circle of that cam…….

View attachment 1957431

I can measure it. Do you want the slope of just the base circle or the lobe?

 

[Geoff 2]

That is the WORST place to put EDM holes because it is where the max load is. You are taking away surface area where it is most needed. EDM hole should be off centre.

 

[66 Sat]

That is the WORST place to put EDM holes because it is where the max load is. You are taking away surface area where it is most needed. EDM hole should be off centre.

That's where Howards put their holes on their Direct Lube lifters. Surely they know what they are doing?

Howards Cams 91118 Howards Cams Direct Lube Extreme-Duty Mechanical Lifters | Summit Racing

 

[PRHeads]

I can measure it. Do you want the slope of just the base circle or the lobe?

Across the lobe on the base circle is fine.

The base circle is where the odd wear line is appearing.