DavidNJ

Has anyone tried using oval track solid roller lobes on the street? These are less aggressive than drag lobes, however much more aggressive than street lobes. Some are available for lift restricted classes, which would be fine with the LS1, which seems to be done by .6" lift with even the most aggressive porting.

Ideally, you would get 20-40% more area under the curve without an increase in overlap. Hopefully, the cost would be just tappet noise, lifter adjustments, annual or so valve spring changes, and maybe a $4k cost for the valvetrain.

I was thinking of a setup with Morel solid lifters, TD or Jesel shafts with a high ratio, 1.55 springs with about 230-250 at 2" installed height and in the high 500# range over the nose with lift between .650-.675". That would be a Comp Cams 26089 or equivalent Isky or PSI. Valves would have to be +.200s...which I guess are custom parts.

ARE makes reasonably priced valve covers with valve spring oilers, which they say can be plumbed with a wet sump system.

So the questions:
Can you fit a 1.550 spring in the LS1, LS6, or AFR heads? The answer appears to be yes.

Would you make the valve fit the LS1 guide size or enlarge the guide?

Do you have contact info (web page, e-mail, or phone) for Morel? And who sells their lifters?

Can you/have you run an oval grind on the street?
And last but not least, do you think this would work?
Thanks,

David

J-Rod

We race in a lift restricted class already. The type of lobes we use in a class like that are "launcher" lobes which intentionally induce valve float to gain extra lift. This requires you to be on your game as far as your springs.

Anyhow, a solid lift lobe is different in several areas than a hyd. roller, much the same as a solid roller lobe is different from a hyd. roller. For instance, on a solid roller the initial ramp differs from hyd. since you have lash , and not preload.

I'm sure you could adapt a lobe, its just some changes might need to be made before hand to ensure proper operation.

Lets just say you can use a lot of differnet lobes a lot of different ways...

v8pwr

iTrader: (19)

I'm slowly building a motor that will have a valvetrain similar to what your describing . I spoke with Brian T. @ TEA (great help) and he suggested that since I wanted to put in new guides anyway that we convert to 5/16 valves . The difference between 8mm and 5/16 is only a few thousanths but it makes it easier to get parts . I'm using Manley ICD retainers and instead of having a lock made for 8mm I'll just use an off the shelf 5/16 lock . Also 5/16 valves come in a variety of lengths . I want the solid roller for upper rpm stability and I would be more comfortable setting lash than hoping the preload is right and it won't crap out @ 7000+ . The less aggressive lobes would aid spring life as well .

DavidNJ

The Manley ICD's are probably a good idea if they are available for the spring. On a new purchase, they are only a few $$$ more and both reduce weight and allow some oil to land on the inner spring.

I was worried that the guide would be come to thin in some sections with the thicker stem.

The lobes I am thinking about shouldn't launch the valve. I use a similar grind (Comp Cams MA) on my late model with 1.8 rockers (.090 backspaced Crower stainless). Similar to an MH grind with 1.7 rockers, however with a slightly more aggressive ramp.

I will check with the cam vendor though.

Does the 1.55 spring also fit? Does a 1.650?

Thanks,

David

v8pwr

iTrader: (19)

Why would you go to thicker valve stem ? The 5/16 setup is about 2 or 3 thosandths smaller and you won't gain the weight of a thicker stem . I also recommend this so you have fewer problems finding quality parts .

DavidNJ

The 5/16 SBC valves will fit right in the LSx head? If so, I guess a +.250 SBC would work.

Jason99T/A

iTrader: (21)

Just have the guides re-sized and the 5/16" valves will work great. LS1 has an 8mm stem from the factory. Stay away from the heavy 11/32" valves if at all possible. There are PLENTY of retainer/lock setups for the 5/16" valves.

Jason

LOnSLO

iTrader: (15)

Like Jason said. You will need complete new valve guides installed and honed if you're going to 5/16".

DavidNJ

Would probably be using new AFR 225cc heads, milled to 58-59cc. Would they come with the bronze guides?

Or would I need to that done?

Jason99T/A

iTrader: (21)

They will come with new guides, but will need to be re-sized for the 5/16" stem. This is generally done by installing a new liner in the guide and honing it to fit the new stem. Or, going with a completely new guide and honing to get proper stem to guide clearance.

A new valvejob is required when doing any guide work.

Jason

z98

I'm sure you can use $4k a LOT more effeciently than that to make more power.

DavidNJ

Not really. Once you set fuel, emissions, noise, and torque curve goals, there is only so much you can do. This already is after headers, X-pipes, highflow cats, big intake, big TB, heads, and clutch upgrade.

Displacement is a also not an or. And ranges from expensive (383 stroke) to very expensive (427, 434, 441, or larger bore & stroke).

At that point you are looking at the cam and revs. One glance at virtually every LSx torque curve, and you can see it go south like a 355 SBC through a 2v 4412 or 4v 390 cfm. Getting air in the engine while meeting the other objectives requires overcoming the limitations of the 2-valve OHV configuration. Those limitations are primarily mass, flex, and curtain area.

Here we are tackling them head on, with hopefully a configuration that will provide an adequate valve, valve seat, and valve spring life.

David