cam timing for 911/81
 

I can't seem to find the cam timing specs for a 911/81 motor. Wayne's book has a void in that particular space. 1977 Carrera
Seems similar years of CIS use .6mm, but I'd like tyo be sure.
Does anyone know the appropriate specs?
Thanks in advance!

Jon,

If that is the Carrera 3.0 then the cams are the same as the SC and 84-89 Carrera. There are 3 different settings for these cams depending on the year and port size. Early 3.0 Carreras had the timing set at .9mm-1.2mm. Many SC engines had the cams advanced to 1.4-1.7mm and the 84-89 Carreras set the timing to 1.3-1.5mm. If you have the big ports I'd use the retarded number (.9-1.2mm). If you have the smaller ports (34mm) I'd use the advanced number (1.4-1.7mm). A good compromise is to use the 84-89 Carrera setting.

If you have 2.7 cams then I can't help you. A useful upgrade would be to install an SC grind.

-Andy

Hi Andy,

Thanks for the reply. It is indeed a 2.7. It came with a 75' Targa I recently aquired. The motor number (911/81) was a bit odd, but in Wayne's book it shows it as a 77 model year 2.7 engine. Unfortunately there are no specs for that particular model. Does anyone know if .5-.7mm, with .6mm being optimum would be correct?

HI Jon
The cam timing for 1976/77 engine's ;911/81, 911/82, 911/84, 911/86, 911/89, 911/85 are all 0.4-0.54 with cams L 911 143 00 and R 911 144 00.

the Carrera 930/02 and 930/12 is 0.9-1.1 with cams L 930 147 08 and R 930 148 08

regards mike

Thanks Mike. I set it up @.6mm, and now can't find the paper I wrote down the cam numbers on. Back-in I go.