Lifter rotation

[baz]

I'm looking at my cam and lifters to make sure they are useable,  I've measured lobe taper and lift both seem good. I've checked the lifter crowns and they have a convex surface all measure out the same or very close. They spin ok in the bores and fall under their own weight.
What they don't all do is rotate as the cam is turning. The exhausts rotate but the inlets don't.  I just have the crankcase bolted up with only cam and lifters installed. Do the lifters need the pressure from the valve springs before they follow the cam properly and rotate?  Or should they rotate just under gravity with the case on its side on an engine stand?

[baz]

Well after a day messing about trying to see why my lifters weren't turning I tried some cam shield on the lobes and found this makes the lifters all turn. I had just been lightly oiling the lobes and lifters.
So when the engine is running and the cam shield has washed away, the oil will do the same job of allowing the lifters to turn?

[Udo]

Most lifters have no or the wrong radius , so they can not turn right . And yes they need some pressure

Udo

[baz]

These are jpm cam and lifters, the lifters have a crown of .05mm and the taper on the lobes measures .03mm around the circumference.  All are turning sweetly with cam shield applied and just using gravity with the case on its side.
I'm thinking of switching to tp lightweights while the engine is apart. I've read they will work with the raptor cam.

[Udo]

JPM lifters radius is correct

Udo

[Frallan]

....and so are TP lifters. I gave Johannes the specs of TP lifters and he gave me thumbs up with his JPM cam.
So this is what is running in one of my engines.

[RobbyKo]

Hello Udo, would JPM cams also fit to your lightweight 59g lifters?