[Jay S]

Originally Posted by dataway

I'd bet about 90% of those shop builds are 100+ hp over stock figures and using pretty aggressive cams.

The demands on HFT components have increased, while the materials used have remained static, a logical consequence would be more failures.

I'd think if it was a matter of no one making quality lifters then failures would be universal, they would all fail within a few thousand miles. If it was only certainly manufactures then that would have become evident almost immediately.

I suspect it's a combination of demands being made on geometry and components they were never designed to withstand ... and I have a feeling a lot of clapped out old equipment is being used to machine these components ... how much high quality HFT cam grinding equipment is being made now?

I think the tolerances for lobe taper and lifter crown are way looser than they were 50 years ago. You get a cam with taper 0.0005 off, and a lifter with crown 0.0005 too low and combine them ... failure no matter how hard the lifter.

There is no cam manufacture out there now pumping out millions of HFT cams for OEMs that require a minimum failure rate .... so the quality slides, the machines are not worth replacing, the market gets smaller and smaller ... all this leads to sloppiness.

That is my thinking also. As for Butler’s 50% failure rate, all I have ever seen or heard of them recommending is Compcams XE grinds, which is not helping them. Those grinds are very aggressive, and are the most difficult of all hft’s to break in properly, the lifter contacts the lobe right to the edge of the lifter, and when the lifter is not machined all that well at the edge. It makes for very for troublesome break in’s.

I think companies push the performance of their lifter face grinders, they push as many lifters thru until it barely meets the minimum requirements for surface finish. Lifter face grinding seems to just get worse and worse. The lifter is not finished to the outside far enough, sometimes it is too rough, sometimes the machining is not even straight.

I have never lost a cam during a break in, a lot of people have though. For me, when a cam did fail, it was always in the first 3000 to 5000 miles, some at 10K looked like they could fail at anytime, but were still working. So when I hear a report that says the cam broke in, and all is well, I still am a bit skeptical. How much of the taper was lost during the brake in because the taper was poorly done on the lifter or cam, and or a component was soft? You simply do not know, and here lately since 2020 the machining and poor quality parts in general has been a dumpster fire. We don’t have time to tediously check everything either, so all I try too do is pick the best parts you can find or afford, and wait and see. Best you can do on a HFT is Nitriding, a good lifter finish, possibly DLC coating, and a profile that matches what your trying to accomplish with your engine combo.