Degreeing cam?

[fuzznut5197]

"While I have the chance", I want to check my cam to see if the 640 specs are correct, or an 8-year typo by S&S. So far, I made a disk with a 1 1/8" hole to get sandwiched between the rotor and compensator and, since I'm using the comp nut for movement, I can only go "backwards" with the wheel. TDC accurate using a centered TDC flywheel mark in the window? Still need to kluge a way to position the dial indicator accurately. Anyone have any tidbits of advice?

[Billy]

You really need to turn the flywheels both ways. Why not mount the degree wheel on the pinion shaft and turn the flywheels with the comp nut.

Buy or make a piston stop to screw into the spark plug hole then gently turn the crank by hand until the piston hits the stop, now "0" the degree wheel, now reverse direction of the crank until the piston hits the stop again, now read the degree wheel and divide the reading by 2, this will give you dead nuts TDC, now turn the crank to the new found TDC and "0" the degree wheel again.

Don't know what you have for an indicator but it needs to be mounted solidly to the case with the plunger directly in line with the lifter travel.

Now you can proceed to check your cam.

BTW, you'll want a piston stop with a hole through it to relieve compression so the crank will turn easy and not want to spin back on you.

HTH

[Admiral Akbar]

This an EVO or TC?

Max

[fuzznut5197]

Thanks Billy, I should have mentioned that the entire primary is off, heads are off and jugs bolted down with pvc, yes Max it would be the 124 evo. 

[jsachs1]

Fuzz,
I'll put up a picture in the homemade tool section(maybe by tonight)of a simple degree wheel fixture,that will enable you to mount ,and turn the engine in both directions.It'll take a piece of solid 3/4" round,a lathe,and a drill and tap.
John

[fuzznut5197]

Thanks John, I don't have or have access to a lathe, but would still like to see the setup.
I found something at work that looks good for the dial indicator mount. 2 tightenable ball joints
at each end and 2 rods, don't really know how to describe it.

[fuzznut5197]

OK, the data is in.   

Apart from peak lift being about .637", the evo 640 cam specs are exactly as advertised.

25/60   65/20   .222/.192   confirmed.

So the evo 640 and the TC 640G are NOT the same. I wonder why that is.

Also found my cam is installed a little over 2 degrees advanced.