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    993 2V question

    anybody know why the 993 or for that matter any aircooled porsche couldnt use a DOHC design with 4 valve heads? or even a SOHC design with 4 valves?

    Re: 993 2V question

    I seem to recall it was a cooling problem, couldn't get rid of the heat fast enough.

    Re: 993 2V question

    that sucks; could have kept that design!!!

    Re: 993 2V question

    Quote:
    bostonmini said:
    that sucks; could have kept that design!!!


    Aside from the 4-valve heads (yes, cooling was insufficient), they got away from aircooling because of noise and emissions reasons as well

    Re: 993 2V question

    grant, any ideas how long cars like ur 993 will be good for before significant rot and overall wear makes them an antique? i want one, but damn, its getting to be 10 yrs old:(

    Re: 993 2V question

    Quote:
    bostonmini said:
    grant, any ideas how long cars like ur 993 will be good for before significant rot and overall wear makes them an antique? i want one, but damn, its getting to be 10 yrs old:(


    You must be joking. The 993's are very rust-proof and bullet-proof. They'll be strong for many decades. Even the early 911's (pre-1976 were not zinc dipped for rustproof) have MANY wonderful original and restored examples. Don't worry, there will be 993's throughout your whole lifetime that will be excellent examples. Heck, there are still many wonderful 356's out there that look and drive better than new.

    There were 4 years of production numbers in the thousands and these cars are very well loved and well maintained. They are built to have the engines and transaxles rebuilt too (unlike in the 996 and later cars which have to be discarded and replaced).

    Re: 993 2V question

    Quote:
    Grant said:
    Quote:
    bostonmini said:
    that sucks; could have kept that design!!!


    Aside from the 4-valve heads (yes, cooling was insufficient), they got away from aircooling because of noise and emissions reasons as well



    That's why when Porsche went to 4 valve heads on the 935/956/962 they became water-cooled, while the cylinders were still aircooled.

    Re: 993 2V question

    grant u just made my day! always wanted my first super/sports car to be a 993 turbo, and now if ur right, i can get one and fix it so it is STRONG (not worried about breaking a tired/worn out motor!) now i just need like; 80K....

    Re: 993 2V question

    I wish Porsche had just put liquid cooled heads on the newer models, then they could been 4-V's and still had the cooling fan. (Like the 959)

    Re: 993 2V question

    Quote:
    911fan said:
    I wish Porsche had just put liquid cooled heads on the newer models, then they could been 4-V's and still had the cooling fan. (Like the 959)


    Yeah, but they developed the wet sump M96 motor to save money and increase profits. It costs only 1/4 as much to make as the 993 motor. But sadly, they gave away alot of robustness and quality in the process...

    Re: 993 2V question

    1/4 the cost??

    Now I know where the 3.3 Billion to buy into VW came from

    Re: 993 2V question

    The cooling fan on the aircooled engine took a lot of power at high revolutions. I don't mind Porsche turning to water-cooled engines - I am not a die-hard enthusiast in THAT matter. I do regret that they lost robustness and endurance in the new engine generation - just as Grant commented above.

    Re: 993 2V question

    Quote:
    Ferdie said:
    The cooling fan on the aircooled engine took a lot of power at high revolutions. I don't mind Porsche turning to water-cooled engines - I am not a die-hard enthusiast in THAT matter. I do regret that they lost robustness and endurance in the new engine generation - just as Grant commented above.


    Ferdie - you're right that there was some power lost from the fan, but I believe that the belt is designed to slip on the fan pulley when it revs really high (at least my mechanic told me that...)

    Re: 993 2V question

    Isn't the alternator installed inside the fan? I am just curious if this would make sense - besides that does the belt have teeth or is it a simple extruded profile?

    I read some numbers about the amount of air blown through the fan at high RPMs - don't remember the exact number but it becomes obvious that it takes some power.

    Afterall those are all assumptions, I give way to the more knowledgeable.

    Re: 993 2V question

    I'm not the more knowledgeable one here - just reporting what I was told


    No, the belt is not toothed. Yes, the alternator is inside the fan (same belt). The belt slips at very high engine speeds, but it does not cause the fan/alternator to stop spinning, it just stops spinning faster than it would at 4,500rpm, for instance. So, there is plenty of cooling and charging at that speed...

    This could be BS, but it's what I was told by a very good mechanic...

    Re: 993 2V question

    Yeah but didnt the new liquid cooled cylinders take away some of the visceral qulaities of the flat-six? So many people complain about the M96 being so quiet.

     
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