Cams - How To Decipher Them

[James Buchan]

Alright, I've been digging around trying to find info on my cam, I now have the specs on it but how do I translate them into plain english? I mean I've got all these BTDC, ABDC, Lobe lift, advertised lift - what does it all mean? I always thought my cam was near to a Engle FK-8, but by comparing the numbers, mine \"seems\" larger, or smaller if I am reading it backwards

My Cam -
Pauter T3E8
Advertised Duration - 307 deg
Lobe lift - .436\"
Lobe seperation 108 deg

.050 check specs
Duration 272 deg
intake opens 32 BTDC
intake closes 60 ABDC
exhaust opens 68 BBDC
exhaust closes 24 ATDC

lift at valve with 1.1 rockers .479\"
lift at valve with 1.4 rockers .610\"

In comparison here is a FK-8

Advertised duration 298 deg
Cam lift .382\"
Duration 258 deg
Valve lift with 1.4 rockers .534\"

 

[jim martin]

this is how i calculate it out.
-this is a dual pattern cam
-overlap of 56 deg
-intake running duration of 272 deg-
-exhaust running duration of 272 deg-
-intake centreline of 104 deg atdc-
-exhaust centreline of 112 deg btdc-
-this cam is ground on a 108 lobe centre , but is 4 deg advanced.
-don't think this cam is desighned too be run with anything larger than 1.25 rockers.so using .479 lift as a max this would be a cam desighned for torque in a larger displacement motor running between 3000-6500 rpm [guess depends on a lot] .
so is this cam good for your car ,it would depend on gear ratios and more  headflow numbers and vehicle weight.
hope this helps a bit , i know cam science is a mystery there is a lot of variables that would make the same cam act different in every car.
weight/bore/stroke/heads/etc etc.
 

[James Buchan]

Thanks for the info Jim, I thought .610\" might be a bit to high

I actually find that it comes on about 2800-3000 and I hit my rev limiter before it stops pulling - set at 7400, shifting at 7200.

I'm getting good flow from my heads, and the car is light (1660 with me)
I may throw a set of 1.25's on and see if there is a seat of the pants difference.

[Scratchy]

Hey James,

Check out the following page (just scroll down past the index):

Engle Camshaft Specs

If you compare the FK series with the W series, the total advertised duration is quite misleading. The real figure is the duration at .050\" lift. You'll see the FK8 isn't much more than the W120's duration, but just a whole lot more lift with the ratio rockers (easier on the valve train). Basically you can get an idea on how steep the ramp is by subtracting  the .050\" duration from the total duration. At the same lift, the one with the steeper ramp
should give more torque (check the VZ series - I have the VZ 25 in my 1776).
Of course all these cams have different lifts, so they are hard to compare, but I believe this to be a good overall generalization of camshaft theory.  

Sorry, I can't help you with the Pauter, but the specs you gave seem to indicate it is quite a lot more cam than the FK8

[James Buchan]

Thanks Scratchy, I figured the FK8 is one of the more widely known cams as alot of people run them, hence the comparison.

I REALLY like the way my cam pulls, I'm more than happy with it - I just want to understand what it is doing and what else I may be able to get out of it.

I mean it bagged me a 14.11 @ 98 with a stock tranny and street tires on my first day ever at the track so it's gotta be doing something right! I've now put in a close box of Shane's and I've done some tuning so I am crossing my fingers for a 13.xx @ 10X.XX - we'll see on the 13th!

[Scratchy]

We'll see ya there James.
Maybe I'll get some pics of you with the wheels up!