WE TODD DID

iTrader: (2)

Does anyone know what the O.D. of the spring pockets can be cut to? I ordered a set of bare heads, and I need a spring with about 200lbs on the seat, and all I'm finding is a 1.55 od spring with that kind of pressure. Anyone have that sort of experience with these heads?

Richard@WCCH

iTrader: (3)

I found a Crower 1.470" spring that worked. It had around 200lbs on the seat and a bit over 500lbs open (about .650" lift). The tough part is dealing with the retainers and minimal valve tip on the L92 valves. Check rocker/retainer/valve tip clearance very carefully before starting the engine.
Call me at the shop if you need the part numbers. I'll be in on monday for half a day.

Good luck,

Richard

WE TODD DID

iTrader: (2)

Is 1.47 about as big as the spring pocket will go? I know on a standard ls1 head, the intake runners limit how much of a pocket you can have. I haven't personally seen a set of l92's. I found the springs, but I don't think they'll handle enough lift for my application. Something else I'm concerned with, is the installed height of the stock length valves. I was going to consider putting longer valves in the heads, but I'm afraid that if I do that, it will get the valvetrain geometry out of wack since they are non adjustable pedestal mount rockers. The more I think about it, the more problems I'm going to run into.

HTMtrSprt

I believe the only way to cut the spring pocket any bigger in diameter is to cut it higher on the casting and use a small shim under a larger spring seat to extend to the bottom of the stock pocket. Why do you need that much spring?

WE TODD DID

iTrader: (2)

Aggressive solid rollers tend to like heavier seat pressures. Running light pressure with an aggressive camshaft can break lifters, and create valve float. This whole thing I'm doing is experimental, and I just keep running into problems. On top of the spring issue, now I'm having trouble finding and adjustable offset rocker for the heads.

Richard@WCCH

iTrader: (3)

A 1.470" spring is about as big as the stock pocket will allow. Step cutting as mentioned above is an alternative work around, except it will require a longer valve do the the decreased installed height. As you can see in the photo below there's a water jacket underneath the exhaust spring pocket. It really doesn't lend itself to being solid roller cam friendly.

Richard

WE TODD DID

iTrader: (2)

Is that water jacket in the same place as an ls1 (241) head? I have an old junk head that I was working on today, and cut the spring pockets to 1.55, but didn't go any deeper than the original pocket. I drilled a few small holes around the perimeter of the intake pocket and had roughly .100 thickness to the intake runner. I didn't know about the water jacket on the exhaust side, so I guess I'll have to drill a few holes around it and see what I come up with.

Another question, how long are the stock l92 and ls1 valves? And what installed height are they in stock form? I can already see that I'm going to have to get longer valves, so I'm gonna have to figure out exactly how long. I do appreciate the assistance!

Richard@WCCH

iTrader: (3)

Your going to find the exhaust spring pad very thin after machining for a 1.550" pocket. In fact you may break through during the machining process. All these factory castings are a thin wall design.
The factory stock valve lengths are 4.885" on the intake side and 4.920" on the exhaust side. You're going to need somewhere a least a .100" long valve. You might try looking at LS7 valves as they're longer overall and also have a longer tip length. Of course you'll need some aftermarket rocker system to work with the longer valves.
Just an idea........

Richard