Hey all I like many others have the LS1 sewing machine going on and have started to get kinda tired of it! Hell the damn valve train is almost as loud as my exhaust! So does anyone know of a way to quiet the VT down? Like going to a set of aftermarket rockers?

 

First thing is to make sure geometry is correct (wipe pattern) and pushrod length is correct (measure with adjustable pushrod).

 

I have a pretty radical cam on lsk lobes and my engine is as quiet as could be. I have never heard a more quiet cammed engine as far as valvetrain goes. I attribute it to my .100 preload and 65psi warm idle oil pressure. Preload (correct pushrod length) is most important for quieting down valvetrain and a good set of springs imo.

 

well Im running the PRC dual springs, and 7.40 pushrods with the stock rockers, would a set of YT's do well towards quieting my motor down? Also how are the comp rockers that all come mounted on a single bar? Those look quiet interesting. I would need the 1.7 rockers correct?

 

you could dynomat parts of your engine bay that stuff works very well. But other then that on a cammed car with all the geometry being correct (which i am sure Ryne made sure it was) there is not too much you can do. Maybe i am wrong?

 

Oh I have no doubt that mike put it all together correctly, but the geometry is only as good as the parts in this case as they are the stock rockers and not adjustable. I am hoping that an adjustable aftermarket set will allow the geometry to be dialed in to the 'T' and eliminate alot of motor noise.
Even If I did dynamat the engine bay I would still get the valve train noise resonating through the header collectors, so Id like to eliminate this problem at its source!

 

in all honesty, the stock rockers are really good... only thing that needs to be done to them, is get them rebuilt by Harland Sharp so that the needle bearings don't spill out... many guys are using them with 800+ HP.... I've seen quite a few on here say that after they stuck some aftermarkets in there, they had some small issues with them, or costed them small amounts of hp... (not all, but some...)

curious, what's your cam lift specs again?

 

.581 .588.
With the PRC double springs I should be fine up to and a little past .600, to .660 actually, but its noisy as hell!
I too have read of people having trouble with the HS and YT but primarily because of their weight, YT's are supposed to have been re-desinged.
Im just trying to throw it out there to see if there is a way to quiet it down!

 

Stock rockers can be adjusted, but it takes time and working with shims. I doubt it was done or looked at. The YT's are easier to dial in due to the individual pedestals but it does take time as well. If you shim, you will need new pushrods as well.

 

How does one determinr the needed length of a pushrod?

 

The best way is to use a adjustable push rod checker; about $20.

 

Ok, pushrod checker got it. Now...how does one use it? Honestly Id be standing there holding the checker in one hand looking at it like a cave man. Anyone ever seen the movie the gods must be crazy? Ya that would be me with the glass bottle, except my glass bottle would be the push rod checker.

 

If you go through the valve train and everything is 100%, then you might just have noisy components. I've heard of some cam lobes being noisy, and I know that Ford struggled with that on some of the 5.0L engines in the early 90's.

I've figured out on DOHC engines (Hondas) that an oil heavy with moly content will quiet a noisy valve train. Either Red Line Oil, which has a lot of moly, or a good moly additive will quiet the valve train. A heavy oil might help as well, but I don't like that solution.

 

Just something else to look at. When I pulled the rockers off my car, There was probably 10 to 15 thou vertical movement in the trunnion and the rocker it self. Engine was a stock LS6 with around 65K. I had more people ask me what was ticking in my car you couldn't believe it! I installed a set of 1.7 Crane gold rollers and the engine was quite as a mouse. Until I switched to the fast intake with no foam on the bottom! Holy crap do those things echo injector tick!

 

Aint that the truth. I thought I had a vacuum or exhaust leak but it's just the noisy FAST intake.

 

Do a search, there are several write ups on using the checker. Get the preload around 80 to 100 and your valvetrain will be nice and quiet. You don't need aftermarket rockers or anything else, just the correct setup.

 

FYI....

https://ls1tech.com/forums/generation-iii-internal-engine/978541-thank-you-yella-terra.html