Degreeing your cam

[Red Lehr]

I wanted to check with some of you guys about the best way to degree your cam. From what I've seen, most of the time a engine builder will degree the cam before the heads are installed. Is it better to do the degreeing before or after the heads are on ?
Just for kicks, I wanted to check the cam on my 428 (which uses 1.75 ratio roller rockers)  , but I really don't want to tear the heads off to do the job.
Thanks,
Red

[blykins]

When I'm assembling, I always degree with the heads off and with only the pistons/rings in the cylinders that I'm checking.  That way it's very easy to roll the assembly over, easy to get a dial indicator directly on the lifter, easy to find true TDC, etc.  My degreeing fixture is meant to screw into the deck surface of the block as well. 





That's probably the preferred way for almost everybody, because it eliminates most of the variables that can bite you. 

With that being said, you can absolutely do it in the car with the heads on.  You just have to be more cautious and careful so that you don't "stack the tolerances".  Make sure you have a good piston stop that you can screw in the spark plug hole.  If your TDC is off, then the rest of the measurements will be off.  From there, it's just being able to mount a mag base and dial indicator so that you have a perfectly straight shot on the lifters.

[machoneman]

Like the 'big' degree wheel as the small ones are a pain to easily read.

[wowens]

Brent, is your lifter probe ball end to fit lifter socket ? 

[blykins]

No, it’s the same diameter as a dial indicator tip.  Very small.

[My427stang]

You can do it in the car, in fact, in the picture below, I did it on an engine that was running that AM. 

As Brent said, the more joints, turns, pieces, you go through, the more variables you introduce, but it's easily done

FWIW story behind the picture below was 12 years ago when my Mustang was a .040 427, stock stroke.  I ran a Portosonic, 1000 Holley, and an old Isky EE-390, 300 adv, 250@.050, on 108 with no advance ground in, installed on 108.  Ran OK, but wanted a little more street manners, so I cranked it forward.

[jayb]

I always degree my cams with the heads on, probably because I'm always using solid lifters, not hydraulics, and also because I just got used to doing it that way when building SOHCs.  As Brent said, you just have to be careful to avoid any errors.  In the car it is harder because it can be difficult to read the degree wheel, but no reason you can't do it.  I set the rockers at zero lash and put a dial indicator on the valve spring retainer, making sure it won't interfere with the rocker arm as it goes through its motion.  The way Ross's picture shows it would probably be a better way on a pushrod engine, but again I'm so used to doing SOHCs that I usually just go with indicating off the retainer.

[My427stang]

I've always wanted to check at the cam and then at the retainer, .050 duration, then .088 or .0865 and back again at the retainer to see how the duration changes post rocker.  After I stab and locate the cam though, I usually just put the thought behind me and forget about it, maybe with this 445

I also wouldn't mind seeing what a correctly adjusted solid looks like compared to a hydraulic's advertised duration at zero lash.  For example, at the valve, what is the .0106 (.006 * 1.76) duration of a solid cam after lash at the retainer?

Easy enough to do, just never did LOL

[Falcon67]

I prefer to do it with the heads off.  Just easier to mount the dial indicator and wheel.  I also make sure to set the timing pointer and verify TDC on the balancer.  If it's a big cam, I'll put test springs on #1 and cycle through, checking piston to valve, usually starting 20 degrees BTDC to 20 degrees ATDC.