Cam timing

[Plusorminus30]

I am to a point of setting the CAM timing on a 1982 911SC and when I rotate the crankshaft short of the 360 degree Z1 mark, and pull the sprocket pin to set the timing of 1MM, the right CAM will turn right on its own (about .8MM). Is there a way to hold the CAM shaft at the 1MM position, so that I can turn the crankshaft to the Z1 postion and reinstall the sprocket pin to maintain the 1MM measurement?

[Flat6pac]

Youre suposed to have both cams pinned with the Z1 up and the 930 stamping up and then set up to set left cam. Once you have the left cam set, move dial guage to the other cam and one revolution you have measurment available to the right cam.
Bruce

[Plusorminus30]

Yea, that I have done, When I move the left CAM to set up for the 360 degree, the CAM moves back approx 0.6 MM before I can repin at the Z1.

[Flat6pac]

Run the bolt in tight and use the 19mm open/box wrench to support the cam. If you havent bought the fancy tools, you need the bolt tight so you can move the cam back and forth to pin the number you want. Remember take pressure on the pin when your measuring for accuracy.
Bruce

[Plusorminus30]

Thanks, I am pretty sure that is what I need to do, just needed a second look.

[OldTee]

I think what you are observing is valve spring pressure on a lobe of the cam which moves it. Tighten firmly and recheck setting and readjust as needed. I have found that using two 'Z' blocks and digital indicators helps.

[Amberden]

Woooooooooooooooooooooooooooooooow.how i to maintain my engine.tell me some tips .soon

[Plusorminus30]

I have the dual Z blocks and indicators, I remember setting the CAM timing when I replaced just the timing chains with no trouble, but am now completing a rebuild on the engine, and with the reworked heads is where the delimma has been. Thanks for the help.

[Plusorminus30]

Another question, without the distributor installed, how do I confirm which rotation of the Z1 mark is TDC for cylinder # 1, or does it matter at this point, until the CAMS are timed.

[Flat6pac]

Z1 on #1 the intake and exhaust rocker will rock, #4 intake will be moving.
Bruce

[Plusorminus30]

I am tracking on that, was just curious if the #1 piston is in the same spot each time you align the Z1 mark to the case parting line, or if I am 180 out.

[cgarr]

The second time around to Z1 mark #1 would be on the exhaust stroke.

[Plusorminus30]

OK, so until the CAMs are timed, it makes no difference on the Z1 mark reference for TDC on the #1 for the piston position. Thanks.

[Flat6pac]

There is 2 full revolutions to the firing order.
z1 on #1 is TDC
360 degrees Z1 is #4 because the cams have only turned half way so you set #4 as though it were like #1 because both valves are closed and rockers are loose.
Bruce

[Plusorminus30]

It all worked out well, with a little coaxing, thanks for all the help!