Needless to say, but I've got a problem. I bought a set of generic roller rockers from Jegs, first set I've ever owned and they weren't that cheap. Anyway they're stainless steel 1.6 with needle bearing trunions and look really nice, but I can't seem to get them quited down. The engine is a new crate SBC 350 stock heads with a hydraulic flat tappet Comp Thumpr cam duration at 287/305 and intake lift at 487. I've set the valve lash at 1/2 turn past zero and they're still real noisy. Some say anywhere from 1/8 to 1 full turn for roller rockers? And some say they're just noisy? Thanks Guys!
Are you sure the pushrods have enough clearance in the holes in the head? You may have to machine larger holes or go back to a 1.5 rockers as the 1.6 ones may slightly relocate the pushrods in their holes. This may be the noise.
What valve covers are you using? Some have oil drippers or might be too low....... I've seen some that are tapered and are too narrow at the top and just touch the fat aluminum rockers.
There's a lot variables in a valve train that have to addressed, as you build an engine, that have been left out of the discussion, on your part. Have you altered other aspects of it, such as springs, push-rods, lifters, etc. Also, what was done to the engine? Was any machine work done, larger pistons, different pistons, etc. Did you do the old clay test if you did that, to check for interference between piston and valves? And, since you did this, can we assume the pistons are not bumping the valves? Does it have solid lifters, hydraulic lifters, lifters like those made by Rhoads that bleed down? Did you have a discussion with the cam supplier about the right ratio roller lifters to use with particular lifter profile? Higher lift cams, such as the kind that cause the engine to do funny stuff at idle, are not very efficient at idle, causing it to quite literally miss --- thus the sound. Poster #1 has a valid point that, of course, that would have been addressed if any of the above questions were answered 'yes'. And, as post #2 mentions, valve covers do funny stuff if the rocker arms touch them, and can sound like all hell is breaking loose just from what is only a smidgen of interference. Lastly, and I know I'm missing something. If you're using hydraulic lifters, did you lash them at zero for whatever clearance is called for, and then run it until warm and lash them for sound as it's running? Of course this method is messy, and best done with an old valve cover with the top sliced around the top and side, leaving the bottom and bending it out to catch the hot oil. And, please forgive me if I sound like I'm talking down to you: I'm only trying to deal with your problem through a series of diagnostic questions that I'd ask myself, if I were dealing with the same problem
Fortynut has all very valid points and you would do well to go over your motor again and check those things out before you have larger problems. Hope you find out what the trouble is. Pat
I'm running Harlan Sharp roller rockers in the 331 Ford in my 27 and they are a little noisy until they warm up. I also have mine adjusted to half a turn but still noisy. Mine is also on a roller cam, so it is a full roller motor. So I just lie and tell people I am running a solid lifter cam ! Don
Several good points made in this discussion. I can only add that 1/2 turn on your lifters is lilkely the maximun on normal hydraulics. Years ago, we always centered them at 1 turn.
There is no reason for roller rockers to be any nosier than traditional old style rockers. Roller rockers are on almost every luxury car i can think of. Did you think you could just substitute 1.6 rockers for 1.5 rockers without a problem? lots of things happen not all of them good. Get some mechanical help...
^^^^^^^^last 4 words......I went to 1.6 on a 327 and BACK to 1.5 due to an unhealthy sound from the valvetrain.
I always buy my cam and components in one shot from the same manufacturer. It eliminates lots of headaches and they'll always be willing to help you out.
Some SBCs require self centering rockers and some use guide plates for the push rods. Don't mix them. You can run either but not at the same time and you will have trouble if you have guide plates installed and replace the non centered rockers with the centered type. Check with your Cam grinder and ask which you need.
Gun - Did you verify that the pushrods are not hitting/rubbing the cylinder head ? Since now that the pushrod is closer to the rocker pivot, it's also closer to the hole in the head. Also make sure that the cup "edge" in the rocker does not hit the pushrod. Some rockers have a cup that's got a hard edge to it. Most GM Pushrods have a full straight wall, with no undercut at the pushrod ball. Could be interference there also. One last thing...make sure the cup diameter in the rocker and the ball diameter on the pushrod are the same..! I've seen this happen, mismatched diameters. I've run roller rockers on a coupla street car engines with no "extra" noises. I just setup a set of Harland Sharp rockers to run on the street. Keeping my fingers crossed on this one..! I've run Crane, two different Crower and Iski roller rockers on the street with no problem. Mostly small Chevys and a 409 (Iski). Mike
I am using crane's they are noisier then stamped steel rockers but not so much as to be annoying. I run mine @ 1/4 turn past no play. I have run them as loose as 1/8 turn but they were really clattery not because they were rollers but because it was just really loose and I would not do that for anything other then 1/4 mile at a time. I run mine with guide plates and good lifters, that could be part of the problem right there. Someone mentioned the hole size in your heads but your lifters can be as big a culprit as anything. Here is what I figured out a long time ago, when you change one part on a motor to make it better be prepared to change some other parts to go along with it. of course it could be that you are running generic rockers. maybe they are just sloppy. Going back to my original statement roller rockers are noisier then stamped steel rockers.
porkn - Why are roller rockers nosier thAn stamped steel ? Not in my experience..! And there's no reason why they should be if done correctly. Mike
What's to do correctly you screw em down until they are adjusted correctly. Why noisier? Perhaps it is the needle bearings in the trunion or the roller on the snout. Needles make more noise then a busing or ball and socket because they have more room to move and clank. it is just the mature of the beast, bearings make more noise then bushings. Ad to that generic and you just upped the anti (or is that aunty ) ; in theory a name brand rocker should have better quality control and be held to more exacting tolerances. They say that the new and improved bushed rockers (like rollers except with clearanced bushings) are noticeably quieter then standard roller rockers. Just useless info for those who really don't care.
Stock heads? Not even doublehumps? You'll have a mess of problems. 'Lothiadon1940' is right about the pushrod hole being too tight (assuming 'stock head', you can by a tool to cut that hole out but then you'll discover your valve springs are too small for the cam, your .487 lift factored to 1.6 rocker is now a .514ish lift so even if you have Z28 springs they are binding up, you can replace them with pacaloy springs but then you'll discover your push-in rocker studs are pulling and on and on. I would replace the cam with about a 280H, about a .440lift and get some 1.5 ratio rockers - I've even seen where you'll have to run .100 long pushrod with the aluminum rocker or they'll touch the top of the boss the rocker stud. The 280H cam and Z28 spring will work great and sound sweet. But with stock head you'll have many problems to solve to get it right. Been there, done that.
Even the generics are just a quiet as the stock ones. I run them in my small blocks in my transport trucks. These engines run hundreds of thousands of miles with no failures. I adjust 1/2 turn. You did not say if these were vortec heads or not, in my experience the rollers will hit the valve covers if they are the stock height ones.
On my 383 chev I used roller rockers and they were noisy, called the mfg. and they were more interested in defending their product than helping me with the problem, my solution was to buy a TDC tool and find TDC both directions, and split the difference, at the new setting I found a huge amount of slop, readjusted the rockers, bingo! The power increase of this stuff is big so don't give up.
Just an idea here, you may want to check and see if the underside of the rocker is possibly hitting the edge of the spring retainer. Lippy
Thanks guys, just got home from work. I haven't gave it a real visual check as far as the pushrods rubbing the heads or rockers binding against the spring, but I could see the roller tip moving side to side on the valve stems like they were just sloppy loose.
I'm using a set of tall fabricated aluminum valve covers. Yes, tried the stock ones and no way would they work. And I checked the undersides of the ones I'm using for any scoring, but they are clean. The Comp camshaft was a complete set included lifters and valve springs, so hopefully I'm not binding springs.
Nothing against comp cams at all but it seems to me that someone was complaining about a set of comp cams lifters just the other day. yes your rockers shouldn't be dancing around and guide plates are always a good idea but you have to consider the entire valve train when you are chasing a noise.
This could be the problem. The noise is like a loud sewing machine running! And the aluminum sheet metal valve covers make it even louder.
Pull the covers and you'll be able to see if there isn't enough clearance for the pushrods as they move up and down. Good luck.
No, the engine is just a bone stock 350/280 HP crate motor. It has break in motor oil in it now, and the rockers are not as loud when it's cold. Good idea on the cut out valve cover, I'll give that a try. No, the Comp cam came as a set with the lifters and springs.
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