Valve Spring Job

[53wanab]

Recently,I installed a set of Comp Cams 1:85-1 ratio all roller rockers and did not do new valve springs due to some bad advise.I am getting ready to install my magnuson supercharger that I've had sitting in a box for four months ddue to a leg injury.Well,I'm doing good enough to take the plunge but first the valve springs must be done.I also have a new set of valve covers that I had chromed and they look real nice.Big Jim offered to do a picture installation posting but due to another commitment, he could not do the job. I am going to try my best to post before and after pictures duing the install job.Here are the first sequence showing the new valve spring installation.I'm using the Comp Cams beehive high performance springs.These were recommended by Comp Cams to suppliment the roller rockers and supercharger.Apparently there is concern about the positive boost pressure on the backside of the intake valve that this much stronger spring will compensate for.

[SA13355]

Thanks for taking the time to take photos.
Are the chromed valve covers stock?
Or are they custom to fit over larger rockers?

Driving a Hot Rod
Ski p

[53wanab]

They are stock replacement straight from GM.I had them chromed.The only other thing I had to do is to ting in the pvc tray with a ball peen hammer over the cam lock locations for added clearance.No big deal.They fit perfectly

[Purple Penelope]

Craig...what has this done for you performance wise??

P/P

Peace

[JimGnitecki]

Purple Penelope: The stock cam on an 03 / 04 SSR LM4 engine has both short duration (191 / 190) and low lift (0.457 / 0.466).

In comparison, the 05 / 06 SSR engine, the LS2, has duration of around 204 / 211 (I think, if it really uses the 2001 Corvette Z06 cam) and lift of 0.525 / 0.525.

The hotter 2002 Z06 cam which I have in my own 04 SSR has duration of 204 / 218 and lift of 0.555 / 0.551.

Installing the 1.85 ratio rockers on an LM4, versus the factory 1.70 rockers, raises the lift by 8.8% to 0.497 and 0.507.

You can see that this is still very mild, but it helps as it increases the "curtain wall" opening (circumference of the valve x lift) at every point in the valve opening and closing cycle, thus increasing airflow. In addition, it partially "simulates" longer duration as the vlave is open "more" at any given point in the cycle.

On a naturally aspirated engine of this size and type, this generally adds 8 to 18 rwhp, depending on other factors. It is far less effective than an actual camshaft change, but is a lot less costly as not only do you not have to buy the new cam, but more singifiantly you can avoid all the incredible LABOR of installing it in an SSR (a competent shop will charge order of magnitude $1500 labor alone for that swap because of the difficulties involved).

He is doing the right thing upgrading the springs, as the stock springs in the LM4 are REALLY low in spring rate, not because GM was cheap, but because the stock cam specs don't warrant a better spring. Beehive springs of sufficient spring rate from a reputable supplier ARE the way to go. Personally, I would also upgrade the pushrods to stiffer aftermarket ones once you are in there, as that is not expensive nor time consuming to do.

This is a great mod to do in anticipation of a supercharger install, as it will move the new power level up to something greater than the 340 to 350 rwhp from an otherwise stock 03/04 upgraded to blower, and a GOOD exhaust (true dual, not a single muffler pretender) will help a lot more.

Note though that either mod (rockers or exhaust) will nullify the optional Magnacharger 3 year powertrain warranty. (If that concerns you)

Jim G