I guess I should start form the beginning. After all the repairs I did last year, I got the engine on the dyno in the spring. The valves always seemed to be a bit noisy (hydraulic flat tappet), more so than the more radical Engle K8 I ran last year. This one is a special grind from FHO (Comp cam and lifters-.499I/.530E, 230 dur@.050, 112 seperation).

Over the course of the summer I could hear a louder intermittant clicking that would just go away on it's own. The lifters always rattle when the engine is first started cold until the oil pressure comes up. More noticeable if you leave it for more than a day.

I recently redid the preload (3/4 turns past zero) and switched from a diesel 15W40 to a 10W30 Brad Penn (I have a lot of oil pressure). Ever since then (two week ago) I've noticed a louder than normal clicking that seems to come on once the engine is at operating temperature. I switched to a thicker Amsoil 10W40 with no change. In the course of a drive (about an hour) I can sometimes hear the clicking getting louder and then getting quiet on and off. I'd also hear this coming of the throttle between gear changes.

I assumed this is from the lifters. Having reached my limit, I ripped the intake off and valve cover (took me 2 hours-unfortunetly I'm getting good at it). The cam looks mint. I had the engine running yesterday afternoon. I tried to push down on the push rods with the back of a plastic hammer. None of the lifters collapsed, but I could spin the push rods on the lifters that are on the base circle.

Seems like the lifters are good, so now I don't know what to think. Could they still be bad? Could it be the rockers (landy rollers with RAS stands)?

I ordered a set of new lifters from John Arruzza. So.....

Should I take the ones that are in there apart, clean them and try again

OR

Should I replace them, re do the break in and hope that solves it.

The engine is torn down enough that I can do either. I'd like to fix this before the snow flies.

Any and all ideas would be welcome.

By the way despite the racket, the engine runs awesome. Plenty O power and torque, great idle, no missing surging or carrying on.

John,

I'm going through a simular noise issue with my 68 solid lifter hemi. I pulled the valve covers and went through the lifter adjust procedure only to find that they were pretty close to being correct. In the process of cleaning up the valve covers for new gaskets I noticed that the drivers side (the side that had the noise) valve cover had very slight cut marks on the covers made from two of the valve retainers. I decided to make some small dimples in the side of the covers to see if that would make any difference...motor sounds much better now - like a sewing machine on steroids...

Good luck, I hope you find the cause.

Jim
68 Hemi Road Runner

I've got similar issues on my fresh hyd. flat tappet engine, makes me nervous. Actually I'm unhappy enough with the low RPM limit on the hyd. that I'm considering going to solids for the added RPMs. Had several people say large valve covers are like speakers amplifying any valve train noise. So maybe you just get used to it. Greg

I have the same cam in my motor and the same issues with a couple noisy lifters when the engine is warm and run awile. I have adjusted the preload about 3 times with no change and have spoken to Tim about it and told dont worry it`s fine. I have about 3000+ miles on my cam and the noise has not gotton any worse with mileage being put on the motor. Actually have about 1000 miles on the plugs in it and the motor still put out 540hp/538tq at the wheels on a chassis dyno a couple months back. So I would say button it up and drive the wheels off the car that is what I do.

It could easily be the cam lobe design,comp has some that just make a ton of noise.

My 472 hemi is quiet upon start up, then when it reaches operating temp, the valvetrain (comp hyd 292) on all 8 cyls gets noisy (stethescope) and a couple (I think 4 and 7) are noisier than the rest. I fretted over the for a month- even posted a question on here about it and the general consensus was it is normal considering the odd pushrod angles etc..
No issues at all- to date