Baxter2012

I have a 911 S 72 I think, the engine number is non existent that is a topic for another day.
On the cAse there is the 911/53 which I believe to be correct for 72 s, checked the cam timing at 5.3 which should also be S timing.
First question can this engine have T or E cams and they be timed as S?
Second being timed as an S does the engine have to have the S piston with the larger cut always on the top of the pistons or does it matter.
Third, the Mfi has to be set up with the S timing in mind or it will not run correctly.
Engine runs great.
Please help

Steve Weiner-Rennsport Systems

Hi,

Cam timing is specific to the cams so you need to find out exactly what you have.

Pistons MUST be installed correctly for valve clearance as well as for piston pin offsets. The larger cutout is installed to match the larger intake valves (on top).

The MFI pump must be timed properly to match the camshaft profile in use if you want the engine to start & run properly. There is some slop here, but precision is necessary for optimal performance.

Baxter2012

So if it is running good and the timing has been verified as S the cams have to be S the pump set up for S and the pistons S or the valves would be slamming the pistons.
That said with a 911/53 case type it 99% sure that it is an 72 S motor. correct on all the above.

pfsjr

Speaking of 911S, does anyone know if there is a difference in RPM redline between the '73S and '73E?

Steve Weiner-Rennsport Systems

911E: 7100 RPM
911S: 7300 RPM

Its all done by using the respective distributor rotor in each engine.