911s cams in a SC?

munsonbw · 12-13-2006, 05:15 PM

To lead off, yes I did use the search function but only seemed to find info on 964 and 20/21 cams.

I have an 83 Euro SC with the 930/10 motor. That means the higher 9.8:1 CR and larger runners (as I understand it). A fellow Pelican in selling the following cams:

Pair of new 4 journal 3.0 cams made from new billets by John Dougherty, S grind, early style with big nut. $400 firm

Since he was building a 3.2ss, I assume that they will fit as a drop in to my motor. What are early style with big nut? I am not looking to drop huge wads of cash on upgrades, but I was looking to do SSIs, Flowmaster, Megasquirt with ITBs, and upgraded cams. Will I have to cut valve reliefs in the pistons? What are the S cams like relative to a 20/21 for example? I don't mind a little peaky. Since I am not running CIS, is there a better choice than the S? What about upgraded valve springs and retainers.. are they required and what is the cost?

Thanks!

aigel · aigel's Garage

Forget about it. In 81 cams changed from the nut style to the bolt style. This means that the cam sprocket is held on with a nut until 81 and then later with a bolt. The cams will therefore not fit your engine.

That said, you also will not want to run an S cam in an engine that has an intake manifold with a common plenum. Only if you run seperate throttle bodies (carbs or EFI) willt hey be okay.

George

Early_S_Man · 12-13-2006, 05:39 PM

I have never heard of anyone cutting valve reliefs in CIS pistons to clear valves using an 'S' cam. The traditional thinking is that new JE or Mahle Motorsports pistons would be required! There is certainly not enough clearance for valves opened by an 'S' cam to clear the uncut CIS 3.0 piston domes!

munsonbw · 12-13-2006, 05:41 PM

Thanks for the info George.

I did not have my heart set on the S grind or anything, just seemed like a good price (although not really the right time!). I will continue my investigation for good cam choice. Lets assume that I will ditch the CIS in favor of ITBs, what's the popular choice for a hot street/track motor. I know that I will lose some low end, but I kinda like the kick in the pants when a motor really gets on the cams. Besides, I have my seven clone for all out street performance.

Cheers!

Early_S_Man · 12-13-2006, 06:18 PM

The WebCam 20/21 cams are said to be the 'wildest' cams that will clear CIS pistons, and are said to rev cleanly to 7000 rpm. Sounds like a good compromise if you don't want to invest in a set of JE pistons! ITBs and MS should liven-up the response for the street, too!

aigel · aigel's Garage

Web Cam is too pricey. I would go with DRC and with John's advice which one of his profiles will match your application the best. Genreally people tend to overcam the engine - don't do it.

George