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Thread: 2.0L Build Suggestions

  1. #21
    Quote Originally Posted by BURN-BROS View Post
    Dome volume is listed at 38.8CC, how does one attain 10/1 with a 73cc small valve head?

    With the 67 S valves heads get close, but you will loose it once you install head gaskets... 9.3/1 will be the approximate comp.
    So milling the top of a 906 piston is not necessary if you use the head gasket? Or is it even better to mill it (single plug) and use metal rings instead of the thick gaskets?

    Thanks

    Richard
    searching for engine (case) 903742

  2. #22
    Senior Member BURN-BROS's Avatar
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    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

    _________________________

  3. #23
    Senior Member
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    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 .

  4. #24
    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.

  5. #25
    Odd that there is no mention of using a 70.4 mm crank from a 2.7

  6. #26
    Maybe a daft question - is there a way of identifying 2.2 heads vs 2.0 externally without taking them off?

  7. #27
    Quote Originally Posted by Dr_Danger View Post
    Maybe a daft question - is there a way of identifying 2.2 heads vs 2.0 externally without taking them off?
    Casting number (and date code but harder to see when assembled to engine).

    Richard
    searching for engine (case) 903742

  8. #28
    Senior Member BURN-BROS's Avatar
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    Quote Originally Posted by 50/50 View Post
    Odd that there is no mention of using a 70.4 mm crank from a 2.7
    It's a nice mod. You will need to notch the cylinders to clear the rod bolts.
    80x70.4
    DC30
    9.0/1
    34mm intake port
    This is a great touring engine.
    Aaron Burnham
    Burnham Performance
    1071 Avenida Acaso ste D.
    Camarillo, Ca. 93012
    805-240-6931

    _________________________

  9. #29
    Member #226 R Gruppe Life Member #147
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    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

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