roller cam bearing

so i read somewhere that if you put a roller cam in a motor you ahve to put roller cam bearing in to, is that true? Im building a olds big block, and i know i can steal the roller stuff out of a diesel, but id rather not change my cam bearing if i can avoid it. ty

 

It is the front, or sometimes rear, thrust bearing. flat tappet cams "walk" and cause the lifter to rotate. Roller cams don't need to, since the lifter doesn't rotate.

 

flat tappet cams have the lobes ground with a slight taper, which acts to rotate the lifters in their bores, and also to push the cam back against the thrust surface. Roller cams don't have this taper on the lobes, as mentioned the lifters dont rotate. This lack of taper is what causes roller cams to "walk" forward and need positive thrust control

 

Not all cams develop fore/aft thrust. Shiverlays have alot of movement and are bad on this because all of the cam lobes 'tilt' the same direction. Many others simply have ½ of the lobes tilt in one direction and ½ the other direction to balance the push. There is a reason why roller thrust washers are not available for every engine...

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It takes more than a roller lifter to make a roller cam.....most of whats already been covered. The lobe is straight across in stead of having an angle across the face (which makes the lifter rotate). Roller cams also have very, very fast cam geometry for racing....and the roller cuts down on friction.
If the bore was within the right specs, you could use a diesel lifter, you've got diameters, depths, overall heights to work out........plus you gotta have someway of keeping the lifter staight with the lobe.......a connecting crossbar or have the bottom of the lifter stradle the lobe....something to that effect.
If you want a roller cam.....go buy one, and buy a set of good used rollerlifters from a racing buddy......they'll usually give you a discount.

 

A roller cam does not need a roller thrust bearing such as a torrington roller thrust bearing.........it depends on what your trying to do........

 

from my understanding the diesel olds is pretty much the same as an olds v8, the lifter should be the same bore, someone correct me if im wrong. and they should have the bar connecting the two already, so i guess i need to push out at least one cam bearing anyway, the thrust bearing, right? well if im gonna have to do one might as well do all of them. Im not really sure what im doing, going through the ideas in my head, as the ch***is and body are coming together figured it was time to plan something for the motor.

wat i was thinking was porting heads(there 2.072 valve units) building an intake, long ram like the golden lion 413, 425 bottom end, lower compression, and put on 2 6-53 sc's. o and a roller cam, and if that all works out i figured id go for something a little crazy... like adding a pair of big turbos.... figured id need the forged crank for the turbos and rpms, and roller cams would be nice for the rpms too.

and i know i need a new cam as i cant use the non-roller one or the one outa the diesel.