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Mon Mar 19, 2012 1:29 pm

Given a 2110 with a Scat C35 cam...

WTF DOES THIS MEAN??? http://www.vwspeedshop.com/camchart.htm

Mon Mar 19, 2012 1:45 pm

it means you've got a big lazy slob of an engine

Mon Mar 19, 2012 1:46 pm

It means .373@286. .466@286 w/ 1.25s. Run it .

Mon Mar 19, 2012 2:03 pm

ugh,

i have a customer with a scat 2276 with c35 cam in it. Even in a Manx, What a lazy ass engine.

Mon Mar 19, 2012 2:12 pm

I run that cam in a 1641 and its all done by 5.5k

Mon Mar 19, 2012 3:50 pm

what is it intended for? for a bus might not be to bad.

c35 is similar to the W110 with a little less lift.

as far as being done my 5500rpm thats only important is the rest of it is set up to go beyond that. maybe it was built for a bus or type3 and has p/p stock valved heads or mild 40x35.5s. then theres carbs and exhaust to factor in. if thats the case the cam isn't leaving much out thats there anyhow.

it should be a fairly torquey decent daily but don't think it'll burn up the dragstrip or nothin'. if it's running 1.1's maybe swap to 1.25 or 1.3's....ken...

Mon Mar 19, 2012 4:24 pm

I don't know what 'lazy' means, but it's a baja with 31" rear tires so that might answer your usage questions...

what I really mean by that question is what do those numbers mean? I have the 1.25's ready to strap on, but I haven't yet (I have barely managed to tune the thing... I'm very n00b). I bought the 2110 longblock and have had the heads redone with the 1.25-1's in mind, but someone else made the changes to the heads based on things we talked about. I want to know why those numbers matter and how they affect "The Plan".

Mon Mar 19, 2012 5:24 pm

twomonkeysayoyo wrote: I bought the 2110 longblock and have had the heads redone with the 1.25-1's in mind, but someone else made the changes to the heads based on things we talked about.
What are the current specs on the heads? That cam should make good low-midrange power with the right combo and be good in a baja w/31" tires. It's got relatively slow ramps and mild lift at the cam which means it should be easy on lifter bores and valve seats. The 1.25s should improve torque and responsiveness, but won't stretch the powerband any higher, especially if you've got "small" heads on that 2110.

Mon Mar 19, 2012 6:04 pm

Heads are Mexican 043's or 041's with "The combustion chambers... meticulously re-shaped, the valves un-shrouded, the intake runners ported, and the exhausts opened up."

But that's not really the question. I was just wondering what all those dwell and lift numbers mean.

Mon Mar 19, 2012 7:12 pm

The duration numbers are the amount of crankshaft degrees the valves are open. The duration @ 0.050" is the duration, in crankshaft degrees, that the valve is open when measured from 0.050" lift opening to 0.050" lift closing. This is a universal measuring point for VW cams and allows us to compare "apples to apples" or one cam to another. 0.050" is used as there is no appreciable flow below this valve lift. The standard duration number, aka the "advertised" duration depends on several variables not the least of which is exactly how the cam manufacturer measures their cam duration.

The lift numbers are more straightforward. Lift @ the cam is how much lift the lobe has. In other words, the highest point on the lobe - the nose - minus the base circle diameter of the cam = the lift at the cam. Lift @ the valve is the cam lift times whatever ratio the rocker arms are, 1.1:1, 1.25:1, 1.4:1, etc.

There is also lobe separation angle, aka lobe center, which is the difference in degrees between the intake and exhaust lobes at their max lift. Typically most VW cams are 108 degrees. They can range from 105 to 114 depending on the cams intended use.

Mon Mar 19, 2012 7:13 pm

twomonkeysayoyo wrote: I was just wondering what all those dwell and lift numbers mean.
Duration = how long the valve stays open in degrees of crank rotation, as advertised by the manufacturer
Duration @ 0.50 = degrees of duration between opening and closing, measured at 0.50" valve lift
Lift @ Cam(in) = maximum valve lift in inches, measured at the cam
Lift @ Valve (1.1) = maximum valve lift in inches, measured at the valve with stock ratio (1.1:1) rocker arms
Lift@Valve(1.25) = maximum valve lift in inches, measured at the valve with 1.25 ratio rocker arms

Mon Mar 19, 2012 8:20 pm

a C35 is too small for a stroker engine most of the time.

Tue Mar 20, 2012 7:53 am

Thanks for those explanations; they are helpful, (I think...)

So, these are all measurements of how much you can suck or blow and when you suck or blow and why one number is better than another is a matter of 'local' knowledge?

Are there generalizations you can draw? I.E. "The more lift the more you push the torque curve up the rpm range" (an example drawn straight from my ass)?

At what point do you start to think you have too little or too much duration or lift?

Tue Mar 20, 2012 8:16 am

Close! More duration means power band higher up the revs (assuming engine size is constant). As cc increases you can up the duration and still retain good bottom end AND gain top end. You need more info on those heads then match the valve lift using ratio rockers (to an extent) to the head flow capabilities. I wouldnt have thought .419" with 1.1's is pushing those heads to the absolute limits. 1.25:1's could wake it up a little.
Has the potential to be a nice lil stump puller.

Wed Mar 28, 2012 6:55 pm

kadub wrote: twomonkeysayoyo wrote: I bought the 2110 longblock and have had the heads redone with the 1.25-1's in mind, but someone else made the changes to the heads based on things we talked about.
What are the current specs on the heads? That cam should make good low-midrange power with the right combo and be good in a baja w/31" tires. It's got relatively slow ramps and mild lift at the cam which means it should be easy on lifter bores and valve seats. The 1.25s should improve torque and responsiveness, but won't stretch the powerband any higher, especially if you've got "small" heads on that 2110.

That is exactly why I built the motor with that cam. It built it for a squareback which was a heavier car and built to be reliable but strong. I didnt do any head work so left the cam mild.

Wed Mar 28, 2012 8:35 pm

could alway add 1.4's to it. as far as lazy, well there are a lot of things that can do that.I doubt it was the cams fault.