So I got these motors with flat tappet hydraulic cams and lifters. I also have a couple sets of hydraulic roller lifters. I am thinking that I should be abble to just change out the lifters and not have to mess with the springs or anything else since I am not changing the lift, duration, centerline or anything - just making a little less friction and heat. Could just leave it alone and sell the hyd roller lifters, or buy roller cams... Just wondering if there is a down side to it...

Thanks!

I am no engine expert, but I believe a flat tappet cam has a different lobe than a roller cam would. Also I believe a roller cam is made of a harder steel than a flat tappet cam.

Yes, rollers do have a more radical open and close - which is made possible by having the roller. This is also why different springs are necessary. Since I am not changing the cam specs, mechanically it would stand to reason that the roller lifters couldn't "hurt" anything.... Anyone? Anyone? Ferris?

The flat tappet cam lobes are cut on a slight angle, roller cams are not. The flat tappet cam uses the full base diameter of the lifter to achieve its lift and duration the roller lifter does not.

NO, you cannot do that. Rollers cams flat accross the surface and flat tappet cams actualy have a slight tapper to them witch cause the lifer to rotate. They are completly different and cannot be mixed and matched.

That wasn't something I wanted to hear Thanks for the info though. I guess I will just leave it be. Anyone need a couple sets of hydraulic roller lifters

Or just buy 2 roller camshafts? even used ones are ok if they are in good shape.

Michael

Are they for Gen VI motor? Might be interested at the right price. Email me at [email protected]. Thanks

the tapered design of the flat tappet cam lobes and the hardening process used on flat tappet cams are not compatible with roller lifters. the combination will fail in short order. for cheap roller cams check competition products in wisconsin for factory takeouts and surplus. the specs are in the range used in marine and trucks. I got two big block hydraulic rollercams for $30.00 each. they have been in service a long time and work well.