Need Cam Timing Specs., 911L Cam in 2.7L
 

Stock 2.7L with Webers and 911L cams going together today. Need Cam timing specs.
Thanks - Chris

Chris,

What pistons?
Piston-to-valve clearance may be an issue.

For 1968 911L and 911 (both USA and RoW)
Engines 901/06, 901/07, 901/14, 901/17
Left camshaft, RoW: 901.105.109.05.
Left camshaft, USA: 901.105.139.05.
Right camshaft, all: 901.105.110.05

Cam timing spec is: 3.0 – 3.3 mm limits, 3.15 mm desired.

Best,
Grady

Grady, He is using stock 2.7 us version pistons. Problem?

-Chris

911-L cams wont work with a 2.7L cis piston. An Sc or my Dc10 will clear, but still need to be checked.

Wow, Searched and Searched rather than posting and came away with bad info on this one. I guess choices are to cut pockets in the original pistons sacrificing compression or change cams. We were looking for more low end than S cams could provide. We would like to get this 2.7 installed now so what cam would you suggest at this point that will work best with Webers and stock P&C's. Will the stock cam work ok for the time being?
Also we have another 2.7 which will would consider building using the 911L cams. What p&C's are best for this?
Thanks - Chris

The L cams is the same profile as the 911 E. There is some misinformation out there about the L profile, but I have checked and reground many and they are all the same as an E. If you change the pistons to a carb style dome, the DC30 profile fits the L cores and works great.
With the stock pistons you are stuck with a wide lobe center cam. The wider the centers and the less duration you have, the less lift at overlap. (more valve to piston clearance). I have an idea on a custom set that might work pretty good.. let me do some calculations and I will post back later today.

A nice new set of 2.7RS 90 mm Mahle Nikasil have the correct valve cutouts for an 'S' cam and are reasonable cost. An ‘E’ cam would clear nicely.

A ‘last forever’ engine if done correctly.

Best,
Grady

Grady, I am sure you are right. I am thinking that is exactly what the second 2.7 motor will become. Not sure about the one sitting with the L cams in it at the moment. Waiting on John's thoughts on that and I guess we will make a decision to tear it back apart, go back to CIS cams and setup or something else.

Thank you for your timely and informative answers thus far.

- Chris

Ok Chris, this is what I came up with..
stock E is 238/226 @ 1mm with .405"/393" lift on a 102 lobe center.
New cam, 232/224 @ 1mm with .430"/.395" lift on a 108 lobe center.
This should fit a cis 911105141 - 911105142 core as a regrind.
I think we have a good chance at clearing the pistons with this grind, and making decent power too.

John,

Nicely done.

Best,
Grady

does anyone have the cam timing setting for a stock 2.7 ltre with flat cis pistons.My engine would have stock cams and pistons.The motor does have the 5 bladed fan so it should be a US engine. And the car was manufactured in 1977...cheers