GREGGPENN

This is my new 383 setup.

It's got 155# springs, 216/216 .544/.544 cam, with LS7 lifters. All reports say to adjust these between 1/8-1/4 turn. My builder said they're closer to 3/8th on mine.

It's got COMP Pro-mag full rollers. Is it too noisy as-is? (Please ignore the fan is running.)


NOTE: Vid takes several seconds to load!!!



Who votes I need to pull the valve covers and recheck/redo the lash? My call to COMP got a reply of 1/8 turn for "short-travel" LS7 roller lifters. He also said he hadn't heard of a .070" requirement on those lifters.

Orr89rocz

I'd recheck the rockers/lifter preload again. Also be sure its not an exhaust leak?

THE 383 admiral

definitely needs re- adjustment your lift is just under my old build on 1.6 rockers .540 . 570
you can adj all the way to 1 full turn.. I always adj 1/2 - 3/4

nice build!!!!

tpi 421 vette

I would go at least 1/2 turn past zero lash. If you only go 1/8-1/4 turn past zero lash, there is a good chance they will be noisey. I know some say less, but in the real world, they will work fine and be quiet being tighter.

USAsOnlyWay

Hard to tell on a video (you can just pop the plug out of the fan to help diagnose without fan noise as well) but you can always just go another 1/4 turn on each one if you are sure they are all set 3/8 of a turn.

Sometimes depending on the valve covers, there will be more rocker noise. Brand new roller cam, brand new lifters. If anything it could be a bad lifter, but I'd bet it might just be a bit noisy (and maybe an adjustment is off.)

Shouldn't be the cam though if those lift numbers are with 1.6s.

What does your builder say?

GREGGPENN

lift is with 1.6 rockers.

FWIW: I went with slightly milder ramps than the new XFI stuff and threw on stiffer springs to insure better valve control and longevity. Oh, and the lighter valves in the AFRs can't hurt either.

So, with empasis on valve control,,,tigher lash (maybe even close to a whole turn) seems like I'd get max lift as long as the valve closed. And, on a 5500rpm motor, what's the chance of valve float anyway? Especially with my 155# springs, moderate ramps, and lightweight valves?

Also, why would there be any rocker noise if your down to zero lash. You'd think it would have to be in the roller bearings. Could my heavier springs bang the bearings harder? On the flip side, how would tightening the rockers reduce any noise? Still shouldn't be any slack.

My builder is of the opinion that roller rockers are noisy -- though he things mine are a hair loud. But he also likes the 1/4 turn setting (as does a racer friend of mine) because they believe the best trap times are with mimimum lash. (Kinda seems like it would be the opposite to me since you're preloading the lifter -- and hence valve actuation.

Their are two other possibilities with my noise. I know I have a VERY small gasket breach from #3 exh port over to the flange bolt. This happened when I removed the DS header to clearance #3 tube for the steering linkage. Yeah, I reused the gasket because it was late at night. (It had very few miles but I did notice the imperfection during the r/r).

I also had to grind the VC baffles (which run laterally between two rockers). Before grinding, the covers wouldn't sit all the way down. I took off enough to allow a small bit of side-to-side movement of the cover before trying to center and tighten it. But, using a probe, we can't hear any contact against the cover while it's running. Because it's equally loud on both sides, that makes it seem like my pin-hole leak isn't the sound. It simply sounds like rocker noise to me.

The builder ended up saying he wouldn't worry. I'd like it more quiet. Heck, if I pay attention, I can even hear them tapping below 1600 rpms running down the road. (I've got a stick).

(LT4Obsesses thought they sounded quieter than his stock LT4 but I disagree. Plus, we're comparing a new motor to one with over 100k miles.

Oh yeah,,,one more thing. My covers are VERY thick and very stout. Hard to imaging they'd tranmit much noise [unless it's thru the PVC plastic].)

WW7

Gregg, I have to agree with your builder, they sound about like most of the roller rockers I have heard..I have my 1.6 rockers adjusted to 3/4 turn and they sound almost the same as yours do..I also can't hear any difference in mine if I go 1/2 turn or 1 full turn, once the lifter pumps up all the slack is taken up and there shouldn't be any difference. I have however heard quite a bit of difference depending on what material the valve covers are made of, Steel is louder then alumium and alumium is loader then fiber. You can do like mentioned above and tighten them all down a little more, but I really don't expect there to be much difference.Also Im sure there is a difference in the amount of sound from one brand to the next...WW

Midnight 85

Kinda hard to say from the video but I'm going to say that I wish mine was that quiet,,,, and I've did like WW7 i've tried settings from 1/4 to one full turn.

cv67

If its at or near 0 lash you run the risk of the plunger beating up the retaining clip that isnt a good noise. Dont know why so many think running next to preload gives it more power or "makes it act like a solid" (which is pure bs). Give it proper preload and the noise is what is is, youre going to have some with a fair amount of lift, roller rockers etc.
155 lbs wont kill those rockers.

THE 383 admiral

I know full roller rockers are noisy... but that was a little much
they usually sound like injectors
I have as most say junk S.S Pro Comp rollers identical imitations no issues
they just needed parts washer cleaning from debris left on them http://www.youtube.com/watch?v=Fqz6tAXC3mk

hooked073

Id say readjust they are a little loud

383vett

Pop the valve covers off to make sure the rockers aren't contacting the insides. Then recheck the preload.

GREGGPENN

Yeah Ron, the big issue is what's the "right amount" of preload. Since I'm using GM's performance parts LS7 roller lifters, that's the debate. Jake posted where he saw .070" as the "right" amount. Every source I've spoken to says 1/4 turn. You can even see the variance in opinion with only a few posts in this thread. I find this debate interesting.

Categorizing my lift as a "fair amount", is probably something to consider. My cam is 214/214 with .520"/520" lift using 1.5 rockers. It's really a quite rapid ramp -- definitely in the range of a SR cam and/or XFI ramps. Having .550" lift with a 230 cam is much less severe than getting it done with 15 less degrees of duration. That's my take anyway. (Couldn't we compare it to the ramp rate of a 230-deg cam carrying .600"+ lift? I think so.)

Is it possible we're hearing the sound of the valves snap shut -- if Bullet's cam lobes aren't soft enough on the backside, especially with lighter valves and heavier springs?

cv67

Take the timing cover off, weld a 1/2' thick piece of steel on the inside, crank the cover back down and you wont hear any valvetrain noise guaranteed.

GREGGPENN

Well, that was helpful.

korvette4u

THERE IS NO GUESSING ... i have gone through BULL and heard it even more..

THE ONLY WAY : GET A DIAL INDICATOR ! set zero valve lash (with oil or not doesnt matter) add .30 thousands preload, just for infromatiom this puts the preload approx mid point of total travel ... how much is .30? studs are fine thread ASA so about 3/8 to 1/2 turn...and no more!! BTW is doesnt matter rocker ratio, but one thing must not be over looked! the of the rockerroller must be in the center of the valve!! if not then special push rods are required and maye longer stud bolts.
hope this helps

STL94LT1

My car sounds about the same. I have a 224/230 605/622 cam, GMPP lifters, 155# dual springs, and 7/16 Pro Magnums. I'm at 1/2 turn past 0 lash, more or less adjustment doesn't seem to make a difference on noise.

My car has been through several tranformations and it seems like a majority of the valvetrain noise started when I switched from Crane Golds to Comps Pro Magnums.

GREGGPENN

Sounds like we have the same lifters, springs, and rockers. Maybe that helps confirm it could be the rockers themselves.

How much have you fiddled with lash adjustment (before deciding they can't be more quiet)? How much quieter were the Crane Golds? Why'd ya switch?

GREGGPENN

If .030" is the correct adjustment, Mick's math/info shows you'd need 3/4 turn for 3/8th-inch studs -- or --
6/10 turn for 7/16th-inch stud.... So, with either rocker stud size, it sounds like 1/2-3/4 turn is the correct range to shoot for. Again, that's if .030" is the correct preload.

Note: My quote from Mick was pulled from another recent thread on this subject. I couldn't decide if the ratio would affect what's going on at the rocker tip vs the base where it's being tightened!

STL94LT1

At the time I switched from Golds to Pro Magnums I was running a 212/224 521/533 camshaft and a single spring with a 130# seat pressure. The difference in noise was immediately noticable.