The Stovebolt Site Forums The Shop Area Engine Shop Video on Flat Tappit Lifters

The guy's description of the reason for a slight crown on the bottom of the lifter makes sense. He's refusing to deal with flat tappets from a profitability standpoint, not saying that it's impossible to make them work. It all breaks down to "machinists" and/or manufacturers being too lazy (or cheap) to produce a quality product these days. That's a real shame, as American quality standards used to be the benchmark for the rest of the world to go by!
Jerry

I am contemplating a cam change for my 261 which has a cam that's a little too hot for my present setup. I've about given up on the idea of buying an off-the-shelf cam because of poor availability and possibly poor materials too as Powell points out. So that leaves me with having reground what I've got.

I have several cams for 235/261 blocks and several sets of lifters. Some of them are original GM parts produced in the 1950s and some are aftermarket from the 90s. The lobe center angle varies from cam to cam and I know that can't be easily changed but I really don't understand the subtleties of lobe separation. So which to use as a blank for regrinding? 108deg, 110 deg?

If the metalurgy became a problem after the early 2000s then I'm in good shape. I can have cams reground and lifters resurfaced. I can only hope that 235/261 block machining was accurate back then but wear indications I've seen indicate that it was pretty good. The cam wear patterns are predictable. Of course, I have seen individual lobes and lifters wiped out and can only guess at the cause.

As Powell points out there are many issues contributing to cam failure, not least of which is metal quality. That is an issue for cams and lifter both, of course. Then there is the issue of machining time and machine wear. A high volume manufacturer such as Melling will have machines wear out more quickly than a specialty shop and we can only hope that they are on top of the issue.

I have resurfaced lifters using two angles to match a cam and had good life out of it. That said, I used stock springs and limited the revs to under 4000 RPM so maybe that's not a good test. Another situation I reground many stellite shoes on motorcycle cams with good results. The machine was in good shape and the fluid clean and filtered. But these days I'm dependent on other shops for these services. But who?

Jerry you and I have discussed roller tappets for the 235 a few times over the past few years. As I recall you had come up with a solution involving sleeving the lifter bores and using (if I recall correctly) a MoPar lifter. Anything new on that?