Installing the higher ratio rockers will increase the valve accelleration rates which in turn, will require a stiffer valve spring to prevent valve float.

However, the reason why the engine maintains a decent idle is due to the fact it will lower the duration at 0.200 lift because the area under the curve and ramp rate is reduced. Also remember that when you increase the valve spring pressure rates, you are also increasing the lifter plunger loading.

Some day I might have a set of OEM roller lifters sent to be modified to take the additional spring pressures. There is a company that does such modification:

Sherman Racing Products
P.O. Box 1326
3245 Hwy. 1 South
Donaldsonville, LA 70346
Cliff Sherman (225) 473-4923 or (225) 717-1460
J. Allen Sherman (225) 717-146
Email: shermanracing@bellsouth.net

We have 1.9'* in the SSEi with stock springs/pushrods, etc..... It has no valve float all the way up to the 6200rpm limiter even with 140k miles on it. I wouldn't recommend getting 1.9 rockers without springs though, however I feel that anything over 90lb. springs is overkill as well, you're just putting unnecessary wear on your timing chain, sprockets, tensioner, and your using more power to open the valves.

Shawn

So what do I need to buy if I get rockers?

Ls6 valve springs and the installation kit? anything else? New Push rods?

With the modified rockers, LS6 springs and an install kit should be feasible.


If you are going with rollers, throw in some OR pushrods. Those are recommended by everyone with rollers.

So I need these too?

INTENSE™ High-Performance Pushrods


Sorry cant use a direct link but I think you know what I mean

Yes.

They sell two kinds. The lightweight rods, and the oil restricted rods.

You want the oil restricted rods. This is what is recommended for full rollers.

Rogue or someone else can explain more in detail of why you should choose these over the lightweight ones.

While we are on the subject of 1.9'*. I was wondering is that something I need to do with the new pcm?? Can I just leave everything else alone or do I need to do the 1.9 thing?? Will it damage the engine if I don't do new rockers??



Tim

to get the full potential out of the new rockers the PCM should be reprogrammed to raise the shift points and redlines, because the new rockers increase power high in the RPM range

Like sol said, you want the oil restricted pushrods because they restrict the oil keeping more of it down on the lifters, helping them stay "pumped-up", therefore reducing valve float.

Shawn

Ok I see, you have answered my next question which was why OR pushrods. I am pretty sure I had the higher shift points programmed in when I bought my new pcm.


Is the new rockers and springs and pushrods something the average car guy can do or do I need to have it professionally done??


Tim