Ultimately you will have to mock up and see where you are at. The heads are a pretty decent variable now as well as head gasket choices. VictorReinz is thinner than Elring.
I have not had the piston in my hand, I am going off of Mahle Motorsports printed data for that piston. If the data is correct then the numbers I have given will be close.
I have ordered the cylinders before and are nice, but you will need to run the 906 cylinder tin.
Aaron Burnham
Burnham Performance
1071 Avenida Acaso ste D.
Camarillo, Ca. 93012
805-240-6931
_________________________
I've had 3 '67S projects lately and the head volumes have averaged 69 cc . So with a 38.8 dome volume and a .7 mm deck height the CR would be 10.8 : 1 I measured the dome volumes
at 36.5 cc so began with a CR of 10.2 : 1 .
So long as the subject is hot-rodding, a question for those who might know: What kind of compression ratio might be "safe" with a 2.0-2.5 street engine running 91/93-octane gas through a modern EFI system, such as Motec? The 2.0L Cup engines are very, very cool—but are stuck with carbs (Solexes, no less). I wonder how closely the CR recommended for early air-cooled 911 engines is tied to safety margin with carbs or MFI…
Happy with carbs for now, but the more and more I read about EFI systems with PMO throttle bodies (or anything that allows use of the factory airbox), the more I am tempted for the next time the engine comes out. Call it mid-century with a modern twist, if you will, with respect to the strict adherents.
Oh, and: As someone with a 2.2 who loves the 2.2, there's something even more jewel-like about the 2.0-liter flat six. Have noticed it in several cars.
Last edited by stout; 09-20-2020 at 09:29 AM.
Odd that there is no mention of using a 70.4 mm crank from a 2.7
Maybe a daft question - is there a way of identifying 2.2 heads vs 2.0 externally without taking them off?
Here is an original 911R engine cleaned and measured before rebuild, 80mm. 70.5 cc head and 36.25 dome volume. 10.2cr
Here is a 67S rebuild with the newer(2007) S pistons. 70.7 cc head and 34.22 dome, .25 base gask, .91 head gask. 9.09 cr