Just went thru engine a couple months ago because of constant plug fouling because of ill-fitting head to manifold geometry.

Installed Eddy Performer heads, CC Extreme Energy hydraulic roller cam, bee hive springs(150 pound install height), Scorpion roller lifters and Harland Sharp rockers. Except for a pita rear main leak which I took care of, all was well for some 700 miles,,,no plug fouling and car ran great. Initially used Joe Gibbs zinc oil, at 250 miles installed Mobil 1--5 w 30.

Finally got on it thru the gears,,Passon 4 speed,,not going over 5,800 rpm. Next day car felt sluggish with slight miss that developed into a big miss and loud valve train clatter. Pulled spark plugs on noisy side,,,number 6 fouled somewhat. Pulled rocker cover, number 6 exhaust rocker had rocker to valve .25 inch clearance. Pulled lifter, it was stuck in down position some distance from its retainer. Everything else looks just fine.

Have ordered pair of lifters from Scorpion a week ago,,,not here yet so not installed yet.

Question is: What are all possibilities of what went wrong. When engine was down I had it at very throughly cleaned out,,,was already a likely less than 2,000 mile engine,,installed new bearings and rings etc. Running KN filter.

Scorpion says possible gasket material or silicone got into lifter. I don't know how but I guess possible.

I had deliberately chosen Scorpion because reading of like problems with CC lifters and no issues with Scorpion,,,of course CC likely selling orders of magnitude more product than Scorpion might explain that for what it's worth. And now somewhere I read that CC and Scorpion sell the same lifter

I had almost gone with a solid roller,,,wishing that I had now,,,as now a bit wary of what the future will bring. Car is basically street driven with perhaps a few trips to the track in the future.

Looking for thoughts and experiences that others have experienced with hydraulic lifters collapsing. In 50 years never had one fail before,,,but never had one with 150 pounds of installed height seat pressure before either.

I think I'm having the same issue as this with my wagon ....this is the second set of CC hyd lifters. let me know how the scorpion lifters work

Why the M1 5/30?

Seems like if it has debris in the lifter disassemble it and see. If it is something that would not damage anything like silicone put it back together and run it.

I wouldnt be surprised if lifters are collapsing and getting hammered. 5W20 seems thin for a hydraulic lifter on a BB with hyd roller spring loads.

Performance lifters are often made with more plunger to wall clearance as a fix to prevent pump-up at high rpm when the effective plunger load on the closing ramps become very small and valving response time is at or above its limits. (Of course this is happening as oil pressure is at its peak).

What does the company say for spring pressure.. 150#
is right on the upper limit I think for a hyd lifter

Had the same problem with my 470 build and Scorpion roller lifters. Had a few plungers stick on assembly. Scorpion replaced them. Then after start up and running a bit I had another plunger stick. Gave up and tried Hughes roller lifters. Never had a problem after that. I'll never use Scorpion again. I also bought mine from Summit. Just my

Born and raised in Lincoln.

As noted earlier had read somewhere that Scorpion/Johnson was same lifter as CC's. I did ask Scorpion tech on this, got a politician's answer.

I had the same thing happen on the dyno. Replaced the lifters with Crane hyd. rollers. They pumped right up and never had any more trouble.