Hello everyone, this is going to be long so please bear with me...

I recently built a 470 stroker using 440source aluminum heads and a hughes hyd. flat-tappet camshaft. Initially I had the 440source rocker arms and shafts on it, but because uneasy about the quality of those rockers so I decided to switch to the Crane Gold roller tip rockers.

I'm glad I did too because the "super heavy duty" shafts they sold me had been eaten alive by the roller bearings in their rockers. there were grooves worn into the shafts from the bearings that you could hang a fingernail on.

So I decided to use the stock shafts that I pulled off my 383 magnum when I switched to the new Crane gold rockers because the stock shafts were in really good shape. I checked to make sure I had the shafts installed right-side-up so they are oiling properly.

As per the Hughes instructions, I initially set preload at .08 on all the rockers.

When I start the engine from being cold it runs awesome, idles great, and the valvetrain is very quiet. However, when it reaches operating temperature (approx. 160-200 degrees) the valvetrain starts clattering terribly and sounds like an engine with no oil pressure. I have plenty of oil pressure.(40psi hot at idle) the idles also gradually accelerates from 600rpm cold to 1000 rpm hot once the valvetrain starts sounding like a diesel.

I tried adjusting the preload down to .04 because I'd heard that too much preload could cause noise when it got hot but it didnt help at all. Any suggestions as to what could be the problem?

the specs are:
470 shortblock, 10.0:1 compression.
440 source ported heads
Hughes camshaft 242/246 duration, .555/.569 lift
1.6:1 crane gold roller rockers.
Comp lifters
comp 3/8" pushrods

Any help would be greatly appreciated... I'm pulling my hair out and I'm afraid I might be doing damage to the cam if the valvetrain is that noisy...

Thanks!

How many threads of the adjuster are showing under the rocker arm ? you only want 2 or 3 so that the tips of your pushrods are oiled properly.

Look at the tips of the pushrods to see if they are burning up ???

When I pulled it apart today there were three threads showing underneath the rocker. Thanks!

Did this start when you swapped out the rockers/shafts?

This is the 1st I've heard of a hyd flat tappet wanting lash. Usually they are tightened 1.5 turns past 0 lash, to get the adjustment in the middle of what the lifter can adjust for.

Yes, it was very quiet before and it all started after i swapped the new rockers and shafts in.

and the stock shafts/Crane gold rockers were quiet on the 383 magnum I'm assuming. You're seeing no interference anywhere and no binding on the rockers (needle bearings or side clearance) that could be causing a problem with the lifters and you do have preload for the hydraulics

are the shafts upside down?

On the 383 magnum the stock shafts had stock rockers and were very quiet. I made sure the shafts were right-side-up when I installed them so they should be good there.

If the shafts weren't oiling properly they should make noise all the time and not just when the engine is hot. Is that a reasonable notion?

Thanks!

This is the first time the new Crane gold rockers have been used

Yes, the crane gold rockers were new in the box when I got them.

I'm thinking the Cranes' are the problem just not sure how. I would recheck their slip fit on the shafts cold and when hot/noisy shut it down & undo the adjusters/take out the pushrods & see if any of them are binding(reciprocating and side to side). You'd need to work fast to get em while they are hot which may take several efforts as it may only be one or several that are binding so all would need to be checked while hot. I'm doing alot of guessing here. This is a tough one. Plus there's the (related) idle speedup issue

If you have roller bearing rocker arms, you are going to need hardened shafts. I would get the Crane shafts if you have Crane rocker arms.

I pulled the shafts and rockers yesterday to see if there was anything weird happening and it looked OK to me. The 383 magnum was a low-mile engine and the shafts were still in really good shape.

I thought .08 was an excessive amount of preload as well but thats what the Hughes cam instructions said to use.

I set preload by rotating the engine, setting intake when exhaust was opening and exhaust when intake was closing. I turned the pushrods with my finger and slowly tightened the adjusters until i felt resistance, then tightened 2.5 turns for .08 the first time and 1.25 turns for .04 the second.

Make sure the pushrods are not rubbing on the intake port wall. The Stealth heads have a problem with that.

I don't see anything wrong with your procedures except that .080 which I also think is excessive, is just a little under two full turns of the adjuster. A 3/8 in. fine thread has 24 threads to the inch. One full turn equals .0416. Two full turns would be .0833. I wish I could be more helpful, but I think you'll just have to take them off and examine everything until you find out what's going on.

When I setup preload with a hydralic cam, I do it with the intake removed. Not all rockers get the same amount of turns, there all different depending how much preload they need. Again, there never all the same!
Watch the plunger in the lifter and give it enough preload but not too much. Got to watch the plunger and who cares how many turns I have at the rocker arms, just as long as it within reason so the oiling is good.

Your'll never get it right now without pulling the intake and setting it up by sight. And who cares how many turns you have!! You have to see the lifter to determine wether the plunger is up or down in the lifter when you set it up.

I have been running Crane gold rockers on both my cars for 20+ years now.340 and 440