Hey Techies,

I was curious about anyone's experience on a roller rocker install without head removal. Specifically:

a) I've read in other posts that if you go with a 1.7 ratio arm, you should go with a double spring setup. If you do that, does anyone have experience with using a compressor to fill the cylinder (so the vale doesn't drop into the cylinder), removing the current springs and installing the new? What kind of compressor pressure is necessary?

b) Being a Pontiac man all my life until I bought my C6, I did this operation on my GTO (already had double srping + dampers) and the hydraulic lash adjustment was an "engine running" operation. Basically run the polylocks down until you don't hear clicking and give it another 1/2 turn. A really messy operation that I couldn't imagine on the LS2 with the coil packs being on the valve covers. Is this a zero lash feeler gauge operation on the LS2? So you do it by gauge, sew it up and off you go?

c) And while you're in there, pushrod replacement is suggested as well due to the dual springs and stress angle of the 1.7's? Standard length is okay with 1.7?

Just trying to plan ahead....

Thanks

Gary

 

Gee, did I stump the Shwami?

Check back tomorrow...............

 

The rockers on an LSx are non-adjustable. You don't need a feeler gauge, don't need to listen for any clicking. Just torque them to spec and you're done.

I"s sure you can use compressed air to keep the valves up, don't know firsthand about the pressure.

If all you are doing is adding aftermarket rockers, you don't need double springs, regardless of what ratio rockers you choose. Comp Cams 918s will work just fine.

 

I will vote for duals since they are cheap insurance. Anyone that ever broke a spring and had to pull a head for a valve replacement will agree.

The stock rockers are set to yeild the same preload on the lifter by simply Tq'ing them down to the 22' lbs. There is no lash adjustment like the old solid roller days.

The aftermarket rockers you choose will determine the adjustment proceedure. The use of crane roller rockers for example is like the old-school chevy rocker arm adjsutment. It has an adjusting nut and poly lock that keeps it from turning once you get the proper preload on the lifter. For the preload, you place the rocker on the stand/stud and adjust it for zero lash. Thats the point where the pushrod doesnt move up and down anymore and is just snug. From zero lash you put 60 thousandths preload on the lifter by going another 1 to 1 1/2 turns. The instruction that cam with my set said up to 2 full turns but the valves were then stuck open and the lifters were bottomed out. Tony Mamo also said his were optimum at 1 1/4 turns. Thats what I did with mine and have done this install 8 times.

I'm sure that some know-it-all engineer with no Crane rocker arm experience and a stock LS2 can verify this info and state if I'm wrong.

 

Hi Guys,

Thanks for the info, very good and helpful.

Gary

 

Spin is correct. 1 to 1.5 turns per Tony on my Crane Gold Race. Was getting some excessive clicking (and high rpm float) @ only 1 turn. Also ended up shimming the springs up .004 (per Tony), but I'm also running a pretty non-standard setup.

Have a local tech that uses long wires and a catch tray to do this with engine on (the old tighten until the noise goes away trick). I preferred to have Dustin (@ horsepower sales) do it by feel/hand.

Rick

 

Have you checked into the Pro Magnum Rockers?

Blurb
With the Pro Magnum 1.85 Rockers you get the best of both worlds. Pro Magnum Rockers are made of 8650 chromemoly steel. This material is some three times stronger than 7075-T6 aluminum which is used for most aluminum rocker arms. Our engineers used advanced computer technology (including Finite Element Analysis) to refine the Pro Magnum Rocker. We added strength where it was needed and reduced mass in low stress areas. The result: Pro Magnum Rocker Arms have less weight (5%) at the valve than most aluminum rockers. This means more RPM and valve train stability.