Doing cam timing

Hey Zed,

This is getting pretty frustrating. Wasn't happy with the stability of the flexible dial indicator arm, so I went to work and cut a piece of steel plate to make a solid platform for the magnetic base. Then I started on the exhaust lobe again.

Three things aren't right. First, using the pointer in the bucket cut-out isn't working well because the bucket rotates, and puts force sideways on the pointer and screws up readings. Next is I never get lift more than .403, not 410. This other thing is really weird. Coming off the ramp, valve closed, the indicator slowly goes the other direction after the valve seats. Say I'm off the ramp , valve closed, I'm off 2 or 3 thousandths and it then slowly settles back to "0". Could it be the pre-lube I put on top of the valve stem?

Welcome to the joys of cam degreeing :laugh:
I have a metal plate that uses some of the camcover holes to secure it for the mag base.
If you run the dial indicator directly on the cam you will see that the reading will do the same. It's because of the way the cam has been ground and the lobe probably isn't central to the core .
They are all not perfect and that high spot won't make a difference when it's running.
Second , same again with the lift or maybe there's a bit of discrepancy with the pointer on the bucket throwing off the reading.
Best way to check the lift is direct on the cam.
If it isn't the 410 it's supposed to be then maybe it's a friday afternoon job and a call to APE is needed.
As for the bucket , you need to run the pointer out of the cut out and just watch for it coming round or hold it from rotating with a small blade screwdriver.

I think the sticky pre-lube may be causing the shim/bucket to stick to the lobe. So coming on the base circle, and clearance, it's actually lifting the bucket, then it settles in under gravity and dial indicator spring pressure. The needle is coming down and passes zero (bucket continues up) then settles back down.

Man, this must be alot easier with rocker arms.

VTEC wrote: I think the sticky pre-lube may be causing the shim/bucket to stick to the lobe. So coming on the base circle, and clearance, it's actually lifting the bucket, then it settles in under gravity and dial indicator spring pressure.

I would wash off the sticky lube on that lobe then, you need the dial indicator travel to sweep as smoothly as possible.
I always lube the buckets with my preferred assembly grease (Graphogen) but don't lube the lobes until it's time for the cam cover to go on.

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quote]This is getting pretty frustrating. Wasn't happy with the stability of the flexible dial indicator arm, so I went to work and cut a piece of steel plate to make a solid platform for the magnetic base. Then I started on the exhaust lobe again.

Welcome to the joys of cam degreeing
I have a metal plate that uses some of the camcover holes to secure it for the mag base.

[/quote]

This the most important part for good cam degreeing, a solid stand for the dial indicator(s)

I'm using Torco MPZ. I'll clean it off and just use some light oil.

As far as lift coming up short. When measuring at the bucket, you have to add for valve clearance correct? The more clearance the less lift, and .410 is a zero lash.

Heading for the garage right now. Wish me luck!

VTEC wrote: I'm using Torco MPZ. I'll clean it off and just use some light oil.

As far as lift coming up short. When measuring at the bucket, you have to add for valve clearance correct? The more clearance the less lift, and .410 is a zero lash.

Yes! The lift at the bucket cold will be minus the valve clearance although you should be running zero clearance while degreeing so the valve fully follows the cam at all times..
If you have any lash then fit a thicker shim to eliminate it..

I found the sweet spot on the bucket and I'm at 109.,5 almost there.

I have about .0015" clearance and the lift is .4025" meaning about .405" actual. Should I take the lift any further? This is killing me!

Zed. Do you remember ever checking lift at the bucket while degreeing and have it come out exactly to the cam specs?

I remember a guy I know that worked on the P bikes for years on the West coast. I asked him why the manual has an oddball way of checking valve clearance at various valves with a cylinder at TDC compression stroke, instead of just measuring exhaust and intake of that cylinder. He said it's because the clearances vary at the base circle with lobes at different positions due to valve spring force taking up cam bearing oil clearance, and Kawi thinks this scenario is a more accurate way of checking clearance.

I'm wondering if this could be what I'm looking at. With #4 exhaust valve fully open, full spring force is pushing up on the cam taking up clearance on the right side bearings, while the cam pivots down on the bearings on the left. This will reduce lift measured at the bucket along with shim clearance. Plus I'm using heavy duty springs.

I got exhaust timing on the money, rechecked several times. 54.5 + 17.5 + 180 = 252/2 = 126 -17.5 = 108.5

I've always check the lift of a cam with it set up between centers in the lathe so have never felt the need to do it when degreeing.
I always use zero lash and just concentrate on getting the lobe center figures correct.

But I thought zero lash wasn't necessary with lobe center?

I'm done buddy! Even went back and double checked exhaust. 108.5ex/107.5in.

Should I use the heavy duty locktite on the bolts?