Cam timing - 1970 911T

[limble]

I’m about to time my cams. I tried to pull out a step by step procedure from Wayne's engine rebuild book.

Can you guys give this a once over and make sure it is correct? 1970 911T with stock cam.



High-lift, high-duration Camshaft Timing left side
1. Line up crank @ Z1.
2. Clamp tensioner idler arm.
3. Dot on left and right hand cam in up position.
4. Install rocker arm #1.
5. Adjust valve .10mm (.004 in)
6. Attach dial indicator to #1 (depressed at least .4 in)
7. Install small dowel pin into obvious hole.
8. Tighten camshaft nut to final torque 110 lb/in.
9. Rotate crank 360° lining up Z1 mark. (note how far dial gauge moves). Camshaft should have rotated 180°.
10. Hold cam securely w/camshaft tool and remove nut with crows foot.
11. Remove dowel pin.
12. Rotate cam until valve overlap is reached. (70 911T .091-.106) .098 inch nominal.
13. Replace pin.
14. Rock the camshaft back and forth to check backlash.
15. Hold camshaft and tighten nut.
16. Rotate crank 720° Z1 should be lined up. Indicator should be in range.

High-lift, high-duration Camshaft Timing right side
1. Install and adjust rocker arm on #4
2. Set up dial gauge.
3. Confirm that dot is facing down.
4. Tighten camshaft nut.
5. Rotate crank until Z1 mark is lined up.
6. Hold cam securely w/camshaft tool and remove nut with crows foot.
7. Remove dowel pin.
8. Rotate cam until valve overlap is reached. (70 911T .091-.106) .098 inch nominal.
9. Replace pin.
10. Rock the camshaft back and forth to check backlash.
11. Hold camshaft and tighten nut.

[addictionMS]

sounds about right, I found on my 3.0 that there were generally two holes where I could put the dowel, and the while torquing the cam nut the slop in the pin/hole was pretty big, so one of the two holes brought the clearance into spec and one out of spec because of the play and the direction of the torque.

check it twice, then go away and check it again,

plus check the alignment of the sprokects before doing the cam timing, or else you will be pulling it all apart to pull out a shim and then you get to do the cam timing all over again

Jim

[limble]

Jim,
Thanks. I asked Wayne to go over it and he thought it looked right.
I checked alignment of the sprockets a couple of times and they looked right.
Looks like I'm gonna take the plunge and do it tomorrow night.
I just have to keep repeating to my self "it's only a motor, it's only a motor"