Good tech bulletion on Comp's site refering to Flat tappet
(Hyd and solid) wear problems and recent engine oil formula changes.
click here

 

Maybe, but their words ring hollow to me.....

I had my first cam in over 20 years go flat on break-in 2 summers ago (Comp XE282 mechanical flat tappet). Lost almost half the lobes. I have installed more than just a few cams I my day so I DO know what I'm doing when breaking in a new cam. I was stumped. Stuff like that just doesn't happen to ME!

So, I sent the cam and lifters away to get Rockwell hardness tested......

What harness numbers you SHOULD get:

Cam: ~55
Lifters: ~60

What mine actually got:

Cam: 25
Lifters: 58

Yes, it was tested correctly. No, we didn't measure the tip of an already wiped out lobe where the hardening was worn through. It was tested in about 4 different locations on "good" lobes and on undamaged heels of the cam. Every one of them came up at HALF what it should have been.

Long story short: The cam core was likely NEVER induction-hardened, as it should have been. It was doomed before I ever stabbed it in the motor.

Comp replaced the cam and lifters with another identical set at no charge. It was installed, broken in and has been running for 2 years since then without problems. The first cam just got past their QC checks somehow.

 

Maybe they should look at outsourcing their camshaft production to China....
Apparently you can buy Johnson lifters again.
Used to be the perfered solid flat tappet lifter producers.

Apparently they are back in business again.

 

Good information. Their recommendation for Shell Rotella T is something many people have been findin for themselves for years. That, or Mobil Delvac are excellent products, and still contain many of the EP additives that help prevent or reduce wear in these critical components.

Of course, the entire situation only empahsizes my desire to convert to only roller cams wherever possible. They typically come at a higher price, but the prospect of essentially zero wear over the life of the engine, potential for a far greater variety of lobe profiles, ability to safely use much higher spring pressures, and general reliability of the roller design offsets any negatives in reciprocating mass or initial cost. I understand that a properly applied, installed, and run-in flat tappet system can be very reliable and durable, but I've almost written them off for anything I'll be building for myself.

 

I add GM EOS religiously to every oil change now.