I just saw these on Thunder Racing's site and had a couple of questions you guys might be able to answer. Besides looking pretty damn good, what are the benefits of having these rockers as opposed to Yella Terra's? I'm going to be swapping my stock rockers in the near future with stock ratio ones (read too many threads of LS1's spewing out their rocker bearings, just trying to be on the safe side), but want to know the difference in performance between the two. The price suggests a pretty big difference, but I want to know specifics. How do they mount on the head? Are they a direct replacement for the stockers or do you need valve cover spacers or any other modifications that need to be done for them to fit?

 

Anyone?

 

They mount directly to the head, no spacer. Not sure if they fit under the stock covers, I'll check tomorrow. There's no performance increase unless you use higher-than-stock (1.7:1) ratio. As far as I know they are only available in 1.7:1.

 

What needs to be done,clearence the pushrod hole,shorter pushrod[7.1/7.15,have to measure] and valve cover spacers or taller vc.

They are adjustable and mount like the stockers.I am waiting on vc spacers to mount mine.The YellaTerras seem to work well with less alterations but are not adjustable.

 

Unless your running a lot of RPM all the time, you don't need the shaft mount rockers. You can get a good stud mount roller rocker that will fit WITHOUT valve cover spacers, head machining, or any of that mess. Plus, you won't melt your credit card buying them, which means more money for other improvements.

 

You are referring to the comp cams adjustable 1.75 rockers, the shaft mounts are different, they look like this.



Also according to comp cams these fit under stock valve covers just fine

Quote from comp website about shaft mounts

COMP Cams®, the leader in valvetrain technology, is proud to introduce aluminum shaft mount rocker arms for the GM LS1 engine. The COMP Cams® LS1 shaft rockers require no machining and install under the stock valve covers; making them one of the most cost efficient ways to increase horsepower for this popular GM application. The system increases performance by correctly aligning the roller tip with the valve centerline, yielding more effective lift and less valve stress. Through sophisticated engineering and superior materials, COMP Cams® shaft rockers remain rigid and durable under even the most severe spring pressure.

http://www.compcams.com/Technical/Catalogs/RC2003.pdf

They also offer a 1.8 ratio set part #5054180
http://www.compcams.com/Technical/Ca...L/313-317.html

Btw I just purchased a set of these brand new from ebay for $779 shipped

 

Yeap I run these with 1.7. I like them and they take away most of that LS1 slap. Too expensive though for 400+ level performance but a jewel once you get in the 500+, makes the valvetrain much more stable.

 

I will never buy from this company again. They dicked me over pretty good. IMO go Jessel or T & D. They dont fit under the stock valve cover.
Phillip

 

I figured they would. Just to make sure you don't have aftermarket valve covers or spacers do you?

You talking about the Jesel or T&D not fitting? Cause I know they don't. ... or is it you are saying the comp shaft mounts don't fit? -- The adjustables just advertise they fit under stock vavle cover without clearancing in most cases -- but the shaft mounts they are saying have no problems

 

Those rockers need:
Heads to be machined(required removing)
Shorter pushrods
THEY DONT EVEN COME CLOSE TO FITTING WITH STOCK VALVE COVERS.

If they dont fit the stock valve covers why buy their product. For the same money get a nice beefy shaft mounted rocker. If you look at the Jesel's or the T & D the shaft is much thicker. Bigger is better IMO.
Phillip

 

What are you saying by those rockers? the Jesels, the T&D, the comp shaft mounts or the comp adjustables?

I Pm'd 4thgenretard and he said he has them(the comp shaft mounts as pictured above) running without any clearance issues

I also just noticed you are running the 5.3L heads. I wonder what 4thgenretard is running? Maybe he'll chime in.

 

CamaroSS_2002,
Well, I'll call BS. The valve covers for the LS1 have nipples for the bolt holes which will hit the rockers. The passenger side has 2 dividers which run side to side which will also hit the rockers. Comp said that DRE was making them and I have the ones from DRE with heavily ground valve covers. They don't fit. DRE even said that they dont fit. I called Comp cams, they verified DRE was building them and they don't fit the stock valve covers. That company will never see another dollar from anyone I know.
Phillip

 

Hmm. Would valve cover spacers cure these problems or are there aftermarket ones in the works to clear them?

Just out of curiousity has anyone else ran into these problems?

 

Damnit, Thunder Racing just confirmed for me that they WILL need valve cover spacers... Oh well. I need them, just wish I knew prior.

 

Son of a motherless goat. So they do need spacers then. Why would they state valve cover spacers aren't needed when indeed they are? Are there any good shaft mounted rockers that don't require machining of the head or valve cover spacers? I believe I read the T&D ones on Thunder's site need the spacers.

 

I dunno why they don't distribute this info, if they end up requiring the head to be machined I am gonna kill someone.

I'm waiting on a response from thunder on this question.

Also all of the other shaft mounts available require spacers.

 

I was asked if they needed spacers or will fit under stock covers, and they do!
But I didn't say I didn't have to do a little grinding before the grinning.

 

I'm running these rockers right now. It's already been said yes they do need spacers. I about crapped when I saw how much spacers were. I'm running 1" spacers that I made. (I have CNC machines) These rockers I have only have about 80 miles on them right now. So for now I can't report on durability.
As far as machining the pushrod hole, it can be done with a dremel tool. It's not really machining. It's just elongating the hole in the head where the pushrod goes through. It's just a thin "web" of aluminum. It cuts like butter but you NEED to have the heads off. I bought my rockers when I was building the motor. None of this was a concern as it was just part of the build.

Phil do you still got your rockers?

 

You've got to be joking me, elongating the pushrod hole? WTF -- any chance you have pictures of this? Why does the hole have to be elongated?

Is it also true that shorter pushrods are needed as well?

 

Just curious, how much RPM are you guys seeing? Just trying to understand why you're hooked on shaft mounted rocker arms.

I had read on other posts in this area and the truck area that the Comp shaft mounts don't fit without serious modifications.

If you've ordered them and they won't fit, wny not just send them back and find something that does?