Cam timing, help needed.

bb · 04-01-2002, 09:18 PM

I am setting the cam timing on my 1976 2.7L motor. What is the number on the dial indicator that I am looking for. I am having a hard time geting the number from the books that I have. The car is a 1976 with a 2.7

thanks

zuffenhausen · 04-01-2002, 09:34 PM

You're right... I'm looking in B.A.'s 911 Performance Handbook right now and he's got the checking heights for 3.0-3.6 liter NA engines on page 143 and the checking heights for turbo cams on page 157, but I can't find the checking heights for your 2.7 anywhere. I guess he forgot to put that chart in. Sorry I can't find the number for you, but at least you know you're not crazy.

-zuff

Early_S_Man · 04-01-2002, 10:08 PM

Per the '74 spec book, the 175 DIN hp engine (same from '74 thru '77) uses 0.40 mm -- 0.54 mm, with 0.50 mm being the desired value. With new chains, setting is to the max value, or 0.54 mm, and chain wear during breakin will retard the value to the desired 0.50 mm.

DRV · 04-01-2002, 10:11 PM

For CIS cars with cam no.s 143 & 144 (74-77 911S), 0.40mm - 0.54mm, 0.50mm desired. Source Porsche technical specifications booklet.
Dennis Varney

bb · 04-02-2002, 09:28 AM

that's only .020". that does not seem like a whole lot. When I did my 70T it seems like it had a higher number?

thanks

GIBSON · GIBSON's Garage

bb, CIS cars have very different requirements in terms of cam profile. They will not tolerate lift and overlap that the 70T with carbs or the MFI engines need. CIS profiles are adapted for the different specifications of the engine. Set it to those settings and you'll be fine.

BK911 · BK911's Garage

Sort of on topic...

I came across an old article where somebody recommended verifying TDC. He stated the mark on the fan housing is usually off a few degrees. Since knowing TDC is crucial during cam timing I thought I would mention it here.

Anybody ever verify TDC? Was it close to the markings?

BK