Let's take two comparable cams - One hydraulic, and one solid. For example, look at the CC 268HE, and the 270S... specs are:

268HE: 218/218, .460/.460, 110 LC
270S: 224/224, .468/.468, 110 LC

Both cams have equivilant rpm ranges, and both could be condidered "ideal" for a one specific drivetrain combo, depending on whether the user wanted a hydraulic or solid cam.

It has been said that the solid cam will ALWAYS make more torque. Please help me understand why this is true.

More accurate valve timing and quicker acceleration off the ramps.

So basically, it is an "area under the curve" thing?

427L88,

The difference in measuring comparable cams, say hydraulic to solid is about 8 degrees with today's fast cams, isn't it?

So let's stab the above cams in a 9.3:1 327 w/ Iron camelbacks. Which one will come on harder in the 2500-4500 range? I assume the solid will, correct?

Imho, YES!!

The deal here is that the solid is 224 and the hy- is 218 at .050" duration and both are almost the same advertised duration and fairly close on lift after the solid is lashed!!

This tells me that the solid cam can knock the lifter harder, (i.e., accelerate it faster) then the hy- cam can! And this equates to more suck and thus more torque production overall..

AGAIN, imho, BUT if you take a hy- cams spec's AND grind an identically at lash spec'ed solid cam, both cams should run the same!!

Example Hy- cam, 268/218, 108/108, .450" lift vs Solid cam lashed, 268/218, 108/108 and .450" lift lashed!!

But, (and here's another BUT), since the solid cam is using solid lifters, it can't pump it's lifters up and float the valves like a hy- cam can, but rather it will keep rpm'ming until the rest of the motor causes it to cut out and miss or the valve springs float the valves...

pdq67

I 've only read the discussion amongst the pros here, and it seems like a 6-8 degree difference is the consensus.

Sometime back UDHarold said 8º @ .050".

Talking about generic hydraulic and solid cams as I design them ,The difference at .050" is about 8°, for the aprox difference in valve lash.
However, the real difference is in ramp speed and effective rate-of-lift. Using aprox numbers, a hydraulic cam may open the valve(at rocker/valve contact) at .001"/° at the cam, and a solid open the valve, same way, at .002"/° at the cam. This is why solid cams have much shorter advertised durations than hydraulics, and it is the intake valve opening and the rate of lift at that opening that govern how fast the intake port fills the cylinder. The hydraulic cam opens earlier(More reversion) and opens slower, therefore being behind after TDC. The solid cam opens later(Less reversion) and opens faster, giving more high-lift duration after TDC.
Although different cam companies' cams work in different ways, the above description is generic to all of them......

UDHarold

Thanks, Harold. In looking through David Vizard's Camshaft book last night, he seems to think that solid cams offer little advantage. Specifically, he compared the CC 280 Magnum to the CC 282S, and found that valve motion was pretty much the same. This is contrary to everything I have learned, and this is the main source of my confusion. I pretty much thought that things worked the way you have described above, and it was good to hear an expert confirm it.