Hot 2 liter engines

[G69]

Mfi-

[beh911]

Mfi-

That document is PoA specific and was in response to an erroneous brochure that went out overstating SAE power ratings on all models.

190 SAE/170 DIN for 69S is correct

[Schläfer]

Would a 1969 S be a 2.2 anyway?

[Olivier]

There are quite a few differences actually!

Here you have dyno curves for the 906 (901/20) engine



As other stated, different valves, specific crank, specific heads, specific case ! Here you can see there's an additional closing bot on the 906 case (picture from Porsport)



Plenty of specific bits on a 906 engine. And as said before, it must be a peaky engin to drive on the streets...

Olivier.

[beh911]

Would a 1969 S be a 2.2 anyway?

The model year 1969 cars were 2.0 liters. 2.2 started for 1970 model year.

The pistons, valves, and ports in a 69S are as close as you will get to a 906 power/torque delivery for the street and are a one year only setup.

Refer back to the chart I posted earlier that shows the differences between a 67-68 Weber S and the 69S

[ajwans]

906 pistons look almost like 69s. Maybe higher compression again. Important difference: only 2 rings per piston.

There's pictures on this board somewhere.

andy

[ajwans]

Actually looks like there are 2 and 3 ring versions. http://www.early911sregistry.org/for...67-68S-69S-906

andy

[66S]

I remember someone posted here about a factory hot 2.0 that was streetable because it had S size ports.

[Schläfer]

I've got most of one of the last seasons 2 litre cup motors, which will be built into my 66 motor. When the rules changed to enforce small valves, I bought the whole of the now outlawed top end. It's a large valve head from a 69S (11/68 - 2/69 casting dates though). I don't want to give too much away as I'll start a separate thread, but I've seen the car which the engine came from road tested, and it is mind blowing. It idles nicely and has (relatively) polite manners.

[raspy2point2]

why was the small valve rule changed?