Hi, Bill,
After I wrote the first reply, I did a little research, and both Crower and Comp Cams offer what they call Cam Saver lifters. They're described and pictured in the Crower catalog on page 140 if you want to look it up, and you can do that on line. Comp Cams has a sort of FAQ section in which they address accelerated cam lobe wear due to lack of zinc in the oils on the market now. I also thought I'd explain why roller lifters aren't compatible with your RV cam. All flat tappet cams have a very slight taper on the cam lobes in order to make the lifter rotate in its bore when the engine is running. You can't see it with the naked eye, but if you set up a dial indicator and run it along the peak of the cam lobe, you can see that there's a taper from one side to the other. With a roller cam, you don't want the lifter to rotate, so the roller part of the lifter is ground perpendicular to the long axis of the lifter body and is completely flat across the roller surface. So if you take a normal flat tappet cam with tapered lobes and replace the flat bottomed lifter that rotate with roller lifters which don't rotate, in short order either the corner of the cam lobe will wear out or the roller will wind up with a groove on one side of the roller. Not good. Then there's also the fact that most roller cams and roller lifters are steel, and most flat tappet cams are cast iron, and the wear characeristics of the metals are VERY different and not particulatly compatible in an automobile engine. I'd love to see somebody make a hydraulic roller cam conversion for a Chevy 250, but no one does now, and probably won't ever do it in the future. There's just not enough of a market for any of the aftermarket cam grinders to do that, darn it. There ARE roller cams available for a 250, but they are all solid roller types and all-out race cams which aren't practical on the street. I think the Cam Saver hydraulic lifters might be the best way to go to keep your new RV cam happy, along with some oil additives. The Crower part # for their Cam Saver lifters for a Chevy Six is 66000X3-12(-16 for the V8 SBC). Let us know what happens.
