Cam choice for a stroked shovel

[andri]

So I've had too much time to just sit and think about stuff these last few days, so I got to wondering if another cam for my shovel would be something to look into.

What I have is a 4 5/8" stroke, 3 1/2" bore cylinders with s&s stock bore stroker pistons that according to s&s give a 9.4:1 compression, new s&s heads. Also I am running Jims roller rockers, giving me that 1.5:1 ratio.

When I put this motor together I just put in Leineweber L3S cam I had laying around. It's a nice combination I think, but who knows if anything else might be better.

So I started thinkin that maybe the L5 or the L51 might be better. But looking at the numbers I started having doubts if I could run these with the heads I have, or if they needed some work to them. At this stage I'm not really willing to do that.

But anywho. S&S say this regarding those heads:
It is the engine builder’s responsibility to confirm that adequate valve-to-valve and valve-to-piston clearances exist. S&S recommends a .040" minimum valve-to-valve clearance, and .060" minimum valve-to-piston clearance. S&S cylinder heads for 1966-'84 shovelhead engines will accomodate cam shafts with valve travel of up to .590" and TDC lifts of up to .210" on both valves.

Is anyone willing to chip in if I'd be likely to run into issues regarding valve to valve clearance or with the TDC clearance?

Or maybe I should just be happy with what I have.. But you know how it is

[JBinNC]

You are right to be wary. I have not seen ANY off the shelf head that would support the lift claimed. The claim is based on the spring kit used, and valve travel and valve to valve clearance are almost always inadequate. This is not just S&S, it's industry wide.

You should also be skeptical of the compression ratio claimed. It is almost always lower.

Experimenting with cam selection is the only way to know. There ain't no magic cam. But some cams will suit the motor combo better than others. Using what you have "lying around " is usually the worst thing you could do, but that L3S is a proven good ol' street cam.

Jim

[andri]

Yes I agree that the L3S is a good street cam and I wouldn’t have put just anything in it. It works fine in a light chop, but boredome is a hell of a thing..

Shame I can’t dyno it to see what the output is with this one vs. anything else.

[Dragstews]

You could go with a bigger cam without much worry about set-up ....
S&S made their exhaust valve heads .030" smaller than Oem just for adequate valve to valve clearance with installing radical cam grinds ....

[andri]

You could go with a bigger cam without much worry about set-up ....
S&S made their exhaust valve heads .030" smaller than Oem just for adequate valve to valve clearance with installing radical cam grinds ....

Ok, thanks. I’m going to write to Leineweber and see what can they recommend for the engine.

[Dragstews]

If you have "Facebook" you can chat with Justin Leineweber in his chat box ....

[andri]

Cool thanks!