3.0L SC Oil Pickup Problem

[tom1394racing]

I am getting ready to rebuild my '78 3.0L SC motor for my RSR Clone. The engine will be redone with 3.0L 9.8:1 pistons, 40 mm PMO's and a GE 40 style camshaft. A combo track/street motor.

I am concerned about the oil pickup problem that had plagued some early model 911SC's which were run on the track. I've read that when these early 3.0L motors were run for longer periods at high RPM, that the crankcase would fill with oil eventually draining the tank and causing a loss of pressure. The solution to this problem used to be to add a venturi like pickup to the scavenge pickup (P/N 930.107.314.00).

I would like to use my existing SC style pump for this rebuild. I have the drain sump with the plug in it. Is the current fix still to add the venturi style pickup? Are these still available? Is there a better fix to avoid this problem?

[YTNUKLR]

Originally posted by tom1394racing
Is there a better fix to avoid this problem?

I've personally never heard of it, but what I would do is sell your SC pump for like ~$250 and buy a 930 3.3Turbo pump for about $350, used. THAT one won't have any problems.

[Eagledriver]

Yes, you can add the venturi pickup. I got mine used at Parts Heaven for around 20 dollars I think. You should also update the pressure relief valve. I don't have the specifics on that but you can search for it. It involves a different spring and a guide tube that goes in the spring. These 2 mods will solve the problem according to B. Andersons book. There is a picture of the venturi pickup on page 60 of my copy of the 911 performance handbook (first edition).

-Andy

[Wayne 962]

I agree with YTNUKLR - if you're concerned about oil supply problems, then upgrade to the Turbo pump.

Honestly, it's not a problem unless you're endurance racing or driving at high RPM on the Autobahn for hours at a time (that is how I heard the problem came about).

-Wayne

[Eagledriver]

Wayne and YTNUKLR,

This is NOT an oil supply problem. It's a scavenging problem. If the turbo pump has a larger scavenging section then maybe it will help. I think that the combination of the emergency relief valve opening before the pressure relief valve and the poor pickup of a straght scavenge tube causes the problem. This problem has occured enough to result in several letters to the Q and A sections of Panorama and Excellence.

-Andy