Quieting the Valvetrain after big cams
I want to get some discussion going on what has worked for people who have found their valvetrain quieter than they were expecting. Many of us drive Corvettes, and want the car to sound as refined as when we bought it, or we drive F-bodies and dont want the valvetrain to be louder than the exhaust.
Several folks have mentioned Yella Terra Rockers. If you have done Yella Terras, how much did they quiet the valvetrain? Was it very noticable in the car, or just in front of the engine? Have people who have done the street version of the Jesels noticed the same? I remember the Crane 1.8 arms seemed to make my whole setup louder.
Some folks have had luck with some cams being quieter than others. Is there a cam you have put in that has been surpisingly quiet despite a serious ramp rate?
Some folks might have other ideas or practices, like slightly more preload, or different size valves.
In talking "back in the day" (99 or so) I recall that alot of engine builders said that larger valves often made the valvetrain noisier than a particular cam. I thought alot about that until I heard SW's 422 Solid Roller, which had a valvetrain as quiet as a stock car. (I still havent figured that one out to this day).
What do you think can be done to quiet the valvetrain after a big cam, and why do you think it works?
Chris
(who had forgotten how loud these things were after 2 or so years
) A lot of the noise seems to be the luck of the draw. I have seen cars with identical mods, one was noisy the other quiet. The aluminum block and heads doesn't help much either, it acts like a damn echo chamber. Cam choice will make a diference, single pattern cams tend to be quieter than split patterns, likely because of the natural even, pulsing that tends to cancel some of the valvetrain noise. Last but not least, I have heard some pretty noisy full roller rockers as well, they are expensive and may not cure it.
I think if you have noise there are things you can do to lessen it, but you can spend a ton of money tracking it down and not fix it, screwing up your combo in the process.
I just learned to live with it. A loud exhaust can drown it out

The Yella Terra's have alot of mass to them and I imagine they absorb some of the racket from the valve slamming shut.
Big cams and stiff springs really slam the valves closed making a clicking sound.
Adding headers really amplifies noise from valves closing.
Injector pulse noise - especially after tuning.
I hear a little clicking (sewing machine sound) at idle and a little clicking at about 2250rpm but other than that it sounds fine to me.
I have yet to hear a quiet car with a big cam and headers. Even one with yella terra on.. In the past I owned a '67 Firebird with a big-block 389 running a 270 @50 thou with flat tappet solid lifter cam and headers. That thing had the loudest valvetrain noise I've ever heard! Sounded like a cross between a Singer sewing machine and a hay-bailer!
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I could believe the valve size or seat design could effect the sound a bit.
The cam is the logical culprit for sure. But as we've seen, some people have different results with the same cam.
In theory, the header tube could amplify the exhaust valve sound... more so than manifolds.
Several people have said that the Yella Terras quieted the valvetrain alot. I wonder how that works. Theories?
I really would like my valvetrain to be alot more quiet. Im trying to make this Camaro refined. Imagine!
chris
Interestingly, some rockers/springs/valves made far more noise than their neighbors, no matter what the preload. That was sort of annoying to try and reason or troubleshoot.
chris
I believe LS1 cams with high lift and a relatively short duration are usually pretty noisey; at one point I was going to get a Comp cams 218/0.563, but everyone I talked to with that cam had a huge amount of noise. I lot of people with fast ramp cams like the XER report a lot of valvetrain noise also.
My Yela Terra's w/ shims (1/8 turn preload) was very loud.
Removed shims (1 full plus 1/8 turn preload) car is as quiet as its been. Quiet stock, can hear it at 2000-3000 rpm. Wife even noticed a big difference in noise with the more preload. Course stock preload (stock rockers)is even more, but it was a little louder. So the Yella's do quiet it down some.
. I had a 2000 SS with longtubes but an internally stock motor. With the hood open the engine was pretty loud.
I now have a 98 SS with just minor bolt ons, no headers or anything. It's somewhere between the 2000 SS with manifolds and with headers.
I have a 99 FRC vette as well, with ported heads, T1 cam, longtubes, stock rockers, comp 918s, etc, and it is QUIETER THAN ALL THE REST.
Don't ask me. The old T1s were pretty slow ramp rates, so maybe that's why it's quiet? Don't know what else to say.
Dope
fuel injectors are noisy
air check valves are noisy
valve train is noisy
Restrictor plates for the air checks can help a little. Shimming the rockers so they all have the same number of turns to tighten to 22 lbs might help a tad.
But like very one else I think it's the cams, the stiffer pushrods, bigger valves etc it all usually adds up to more noise.





