GREGGPENN

Love the way the car runs -- especially when cold. As it get near op temp (180ish), there's more noise in the top of the motor.

I suspect the injectors are making at least part of the noise (one sounds even louder than the others). Obviously, that would require replacement and is not at issue.

My builder listened to it and said it's the nature of roller rockers. He said if I returned to factory style, it would be more quiet -- though he said my heavier springs would eat 'em up. That's not really what I'm looking for though.

My clearances are .002" for rod bearings. Pistons are about the same. Lifters are the LS style that GM designates for all hydraulic lifter replacement these days. One of my thoughts is if oil weight can make a difference?

The obvious route would be to try heavier oil since my rod/bearing/piston clearances are slightly higher than stock. OTOH, my lifters are put in motors where 5w-30 is expected. Maybe their clearance is MUCH tighter (and would operate better with thinner oil)?

So far, I've only run 10w-40 and I'm at 3k miles on the 383. Any votes on whether to go heavier or lighter (oil) on my impending oil change? Any other suggestions?

FWIW: I'm running Comp Pro Magnum Full Rollers with just under 1/2 turn preload. They have poly locks. (Rocker noise isn't "bad",,,just that it's louder than stock level IMO. I was just hoping for less noise with lower resistance compared to stock.)

Thoughts, experiences, suggestions?

GREGGPENN

I forgot to include I'm running good oil pressure (30 at idle) and up to 80psi at 5k rpms. It's an updated Melling 3/4" 10542 oil pump IIRC. The cam has 544" lift with 216 duration. (VERY similar to the SR cam.) Springs are 155# dual coil.

Also, I'm only talking about noise at idle.

SaberD

i switched to amsoil 5w30 from mobil1 5w30. i noticed a slight decrease in valvetrain noise after the change.

WW7

Roller rockers have always been louder then stock rockers. When my 383 was built it was quieter then most I have heard with rollers, but now that I have some miles on the motor its noise level has increased to where I would expect rollers to be. I wouldn't go changing oil weight just to quiet the rockers. On a new motor once the engine is broken in and the parts are worn into each other its not a bad idea to adjust the rockers again. I will be doing mine soon at 5000 miles and adjusting them to 3/4 turn past zero lash.When Pete K built my engine he adjusted the rockers 1 full turn, not 1/2 turn at zero lash. I would listen to your builder on matters concerning your motor, he should know best..WW

C409

Headers are also noise culprits ... they tick a lot ...

Midnight 85

I went nuts trying to figure out why I had noise in the valve train, setting & re-setting the lash etc. Then I found out about the RR's being noisy & just learned to live with it. It takes some getting used to but after a while you will accept it.

383vett

I don't think you would want more than 80 psi oil pressure. I can't hear my rockers because of open headers.

cv67

It wont go away, rockers make a little noise and the quicker opening and closing ramps will too nothing you can do just the jature of the beast. Those are man sounds anyway deal with it.

Boy youd hate a solid roller

pr0zac

i wish my car was quiet enough to hear my rockers.

PLRX

turn up the radio

Midnight 85

Or the old Corvette solid lifter fuelie cam known as the 30-30 because of it's lash setting.

slickfx3

some guys are so good they can hear my forged pistons, the built engine is gonna snort and hiss....

cv67

Thats called music

lt4obsesses

So long as it sounds more or less like a sewing machine, that's what they sound like. Oil weight and viscosity will not have any significant effect, I've tried it.

JrRifleCoach

That include the roller tip style rockers as well?

Midnight 85

Sure does.

Muffin

OK, maybe I am dense but can someone tell me how rockers make noise? You have it cinched down in the middle with polylocks which jam it onto both the valve stem and the push rod. Where does the noise come from? Now if we are talking about lifters, absolutely, little suckers will tick given the slightest opportunity. Don't matter if they are roller or flats. Tick....tick....tick.

PDQUIK95

Roller rockers have less surface area touching the stem ,therefore less of an oil cushion against the valve tip at the roller unlike the conventional rocker arm that has a larger surface area with more oil film to help dampen the noise.You will find that the newer hollow sodium filled type valve stems have an even more unique tick to them than the solid stems.The tick actually comes from the momentary slack created in the valve train as the cam lobe unloads from full spring compression and the spring reachs a full closed unloaded position and the hyd. lifter vents remaining compressed oil to the galley not already normally lost thru the lifter seal and bore. The lifter plunger gets a new shot of oil for the next valve lift on the way up, but before it does the lifter oil venting and refill against the lifter plunger actually causes temporary slack and clearance in the valve train which results in the tick at the roller valve tip. The same noise principal applies for a weak or failing lifter. The oil demand and transfer during its cycle is greater because more of the useable oil in the lifter when compressed is lost thru either a failing seal (usually) or from excess clearance in the lifter bore preventing the lifter from reaching full lift with the plunger extended and this creates even more slack when unloaded causing the lifter noise that you hear when its going bad. I personally feel the hyd. lifter plunger is the true culprit that creates momentary clearance when loading and unloading as oil is transfered.Solid lifter noise is obviosly self explanatory with lash built in. So even with proper hyd. valve adjustment, there is still slack in the valve train from plunger movement that is only taken up by oil volume and is controlled by pressure unless you bottom out the plunger in the lifter when adjusting them and that would obviously be a nono. Sorry for the lengthy words but I hope some of it makes sense. I'm just thinking out loud.This is just my opinion but I have been wrong before.The post I see by engle below seems to also make sense though for the noise possibly being caused by roller tip bearing clearances.
Rick

engle1147

Full roller rockers have roller bearings at the fulcrum point those have a minor amout of "slop" in them as does the tip of the rocker that strikes the valve stem. As the tip and the fulcrum bearings get some time on them you'll notice the "slop" increases a bit. Stamped rockers are pretty much all 1 piece so no real "slop" there. The extra "slop" is what makes the noise.

For the most part a valvetrain can make extra noise if the geometry is "off" (pushrod length), too much preload or not enough preload. Thicker oil will not help with roller rocker noise.

Not sure if this helps: I read an article in "super chevy" magazine not too long ago that mentioned there was a low success rate for running 1.6 rockers with the newer XFI cams due to their higher "ramp" speeds....might be something to that or maybe not.

USAsOnlyWay

Can you clarify what you (they) mean by success rate?

I've heard that you want stronger springs than what Comp suggests to prevent valve float but I've haven't heard, or understand, why you couldn't run the 1.6s they designed the cams for.

They are definitely supposed to be nosier and harder on valve seats but haven't heard this...