Engine build questions
 

Hi all,

I have a few questions. I am rebuilding a spare engine I have for my 1971 Porsche 911. The Case has been sent to Ollies and had squirters installed, oil bypass mod, etc. 2.2T heads have been ported and polished and converted to "S" specs. I also have a 2.2 "S" crank for the car along with Mahle 2.2 "S" p's/c's and was sent Carillo rods (used from a friend that races) unfortunately he sent 2.7 rods which won't fit my motor. I could exchange for 2.2 rods BUT I was told if I got my hands on a 2.7 crank that it would be a nice little increase in HP. My question is, is there anything I need to consider when going with this combination of parts? Clearance issues, etc?

Thanks,

Sebastian Roher

Everything will work with the 2,7 crank except the pistons. The 2,2 S pistons have 9.8-1 CR. With the longer stroke you will have over 10-1, and you will also have clearance issues with the 2,7 crank. I'm not sure it would be worth the effort to make those pistons work with a 2,7 crank.

Heck you may want to consider going with 90 or 92mm pistons an cylinders, together with a 2,7 crank you will have a 2,7 or 2,8. However that will require boring the cases and heads.

2.2S pistons
 

I have done a few of the 2.2S pistons on the 74.4 cranks and the skirts need a small amount of work, the additional CR if you don't need/want it can be easily machined from the valve pockets, vs. spending 1000.00 +/- for a new set of pistons.
Mike Bruns