Timing Cams in a 993

[earossi]

Researching things to do as I tear down my 993 3.6 to re-do the heads, I'm looking at re-timing the cams and noticed that the 3.6 does not time out the way my older 911 motors did. According to the manual, I no longer use a dial indicator, but instead use some mechanical positioners to "freeze" each cam in position with the motor at TDC. The cams are apparently held in position so that I can torque down a nut which means that friction then holds the cam in time with the crank. Does this work well? Seems like you cannot fine tune anything, and then there is the high cost of purchasing the two fixture tools that allows me to freeze the position of the cams.

Does this work and what has been the experience of the car staying timed correctly afterwards? I've seen posts where folks are back dating the timing system to the pre-993 days. I would have to have both cams machined to put in a keyway and then would have to find the timing sprockets.

Just looking for comments and opinions on what is on my engine right now. Theoretically, the system that is on the motor should work. I just don't know how accurate things would be.

[Flat6pac]

The key and the pin are still there. Everything fits the end of the cam like your 89.
Trying to recall the installing of the early rocker and shaft and setting the timing to 1.2. That sentense is recall on the posts I have read here because I was trying to figure why early cars can use 964 cams but not 993.
Bruce

[earossi]

Originally Posted by Flat6pac

The key and the pin are still there. Everything fits the end of the cam like your 89.
Trying to recall the installing of the early rocker and shaft and setting the timing to 1.2. That sentense is recall on the posts I have read here because I was trying to figure why early cars can use 964 cams but not 993.
Bruce

Bruce,

Thanks for the reply, though I cannot visualise what you have written. My understanding is that the 964 still had the timing sprocket that was keyed to the cam journal as was the case with my 70, 71, and 89 911's. The late 993's deleted the key from the cam, so there is no way to freeze the timing sprocket to the cam. However, the cams will work in both the 964 and the 993. You just have to have the keyed journal.

[Flat6pac]

I was looking at the 993 Pet and it shows the key way and I was looking at the shop trying to figure why I couldn't use 993 cams without discussing it with anyone but realizing they would set up in the earlier cam carrier.
Bruce