901/06

[super9064]

Is the 901/06 an aluminum sand cast engine?

[jcarpio]

According to Bruce Anderson's 911 Performance Handbook, magnesium cast crankcases weren't introduced until spring of 1968 as the 901/13 (911T), 901/07 (911 Normal) and 901/08 (911S). He also says that before then most engine castings were made of aluminum. He doesn't explicitly say that 901/06 is aluminum sand cast though.

Maybe someone else can chime in with a definitive answer...

[304065]

Yes, 901/06 is a 911 Normal from 1967.

The original 64-66 911 came with different heat exchangers that had a seam inside the clamshell. When this rusted, CO filled the cabin. The result was a comprehensive recall of the HEs, so comprehensive that nobody has ever seen a pair of the originals outside of the factory workshop manual.

The 67- heat exchanger, which is the one that SSI based their stainless version on, was a much more efficient three-into-one design that ended up raising the power of the 2,0 liter "normal" engine to 140 HP instead of the original 130.

As a result, the horsepower gap between the normal and the "S" was narrowed to 20 hp compared to the prior 30 hp. For marketing purposes this was unacceptable, so Porsche used restrictor rings in the heat exchangers of the Solex-cammed (901/05) engine to limit the power back to 130.

Then in 1967, they changed the cam for the normal from 901/05 to 901/06, which had a softer profile, less power, "more flexibility." That's the case you have, it's aluminum.

[super9064]

Just what I wanted to hear. Thanks.