Degree the cam w or wo the heads?

[Tim]

What’s the most accurate way to degree the cam, with the heads on or off?
They’re coming off any way to bump up the compression so for me it’s no big deal.

Thanks

Tim

 

[2000_Black_RT10]

I would say with heads and valve springs installed.

Otherwise.. the cam would be just sitting loose with the chain, which does have a bit of clearance, and in this situation the cam position wouldn't accurate within a degree or so because of the chain lash and tolerances. Heads and the lifters under spring load will hold the cam position better and tighten up tolerances as long as you maintain to rotate the crank clockwise and do not bump it counter clockwise / in the opposite direction. If you miss it, keep going around in the same direction..

 

[Viper Specialty]

Depends...

Gen-1, 2 and 4's have tight timing chains, as well as 3's with adjustable setups. Only stock Gen-3 sets are somewhat sloppy. As long as you have anything other than a stock Gen-3 set, you should be OK either way. Just keep in mind that your lifters are hydraulic, so it you are doing it off a pushrod, make sure it isn't compressing! if the heads arent on, you can go off the lifter body instead.

Also... pay REAL close attention to which lifter is which... I have seen/heard of LOTS of engines timed accidentally off the Exhaust lobe.

 

[2000_Black_RT10]

.. new timing chain set?

Definitely go off the lifter body as VS says.. another reason I'd go with the heads installed.. More parts installed the better due to tolerance stack-ups.. this way you can rely on the pushrod - rocker - spring force to hold the lifter on the cam, i.e. if using a dial indicator.

 

[1TONY1]

Just keep in mind that your lifters are hydraulic, so it you are doing it off a pushrod, make sure it isn't compressing! if the heads arent on, you can go off the lifter body instead.

I agree. That's why it doesn't matter if the heads are on or not. You would not want to have the rocker on unless you have solid lifters. On hydraulic lifters with the head on I use a modified push rod length checker to bridge the gap between the lifter and dial indicator. This way you are not compressing the plunger in the lifter.

 

[Tim]

I don’t have a modified push rod length adjuster so pulling the heads is probably the best as I’m sure I would be compressing the lifter to some extent. I will make sure that I’m on the intake lobe as it’s probably easier to mix that one up when the heads are off then when there on.
Does anyone have any idea the difference on power if this is out a couple of degrees one way or the other?
Thanks
Tim

 

[Camfab]

I think heads off is the only way to go. It's easier to check that the #1 piston is absolutely at TDC with no questions asked. The whole process is much easier in my opinion. I also made an Aluminum pointer and permanetly installed it on the block. At the same time I marked the balancer to match with the pointer at TDC.

Here's a view of what it looked like after putting the motor back in the car.