Everything I've read says that you aren't supposed to swap a used flat tappet cam from one block to another, yet a couple weeks ago on the TPIS site on their garage sale page, I saw a used flat tappet cam for sale. I'm just wondering whether anyone has ever heard of doing this successfully.

 

It has probably been done but you should use the same lifters on the same lobes in the new engine. For a roller cam it would work but I bet more flat tappet cams just go kaput, with rounded off lobes, than work out OK

 

just save yourself the headache and buy a new cam and lifters.

 

Whats the difference between the roller cam and the flat tappet?

 

flat tappets actually have flat (or slightly convex) faces that rely on the oil to allow the lifter to pass across the face of the lobe while roller cams have lifters with rollers that roll across the face of the lobe instead.

 

There is nothing wrong with a used flat tappet cam, if the lobes are not worn out. Doesnt matter what block its installed into. Just dont go reusing the lifters.

 

From Crane's page... pretty much covers the familiar details and gets in a little sales pitch too....



Must new (Standard Design) lifters always be installed on a new camshaft?

YES! All new standard hydraulic and mechanical camshafts must have new lifters installed. The face of these lifters have a slight crown, and the mating lobe surface they ride on has been ground with a slight taper. The purpose of this is to create a “spinning” of the lifter as it rides on the lobe. This is necessary to prevent premature wear of the lifter and lobe. Therefore, these parts will be mated to one another during the initial break-in period. Used lifters will not mate properly, causing the lobe to fail.

If you are rebuilding an engine and plan to re-use the existing cam and lifters (in the same block) it can be done, as long as the lifter goes back on the same lobe it is mated to. To keep your components in order, a Crane Cams “Organizer Tray” part no. 99015-1 would be helpful. If the lifters get mixed up, they cannot be used, and a new set will be required. The new lifters would also have to go through the break-in procedure to mate to the old cam.

Can used roller lifters be installed on a new camshaft?

YES. “Roller” lifters are the only ones that can be re-used. This design lifter has a wheel (supported by needle bearings) attached to the bottom of it. The lobe the roller lifter rides on does not have any taper. This is a very low friction design and does not require the lifter to mate to the cam. As long as the wheel shows no wear, and the needle bearings are in good condition, the “hydraulic roller” or “mechanical roller” lifter can be re-used.


GM used to have a similar blurb in the old "Chevrolet Power Manual", said almost exactly the same thing.