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Thread: The age-old Q: 2.7L or 3.2L?

  1. #1

    The age-old Q: 2.7L or 3.2L?

    I know we've been through this before, but...

    My '70 911E has a '74 2.7L engine with Webers (911, not 911S). It runs great, but the truth is, it needs a rebuild. The compression and leakdown numbers are scary, and the oil leaks are not the easy kind to fix.

    So... do I rebuild it myself with performance upgrades (RS spec, etc.) and live with the weak case, or do I buy a used, but good condition 3.2L engine that needs no rebuild? I can get a sound 3.2L with 80K on it for $7500 with a swap. I figure if I'm going to bypass the 2.7, I might as well go straight to the more powerful 3.2. I am mechanically inclined, and would enjoy rebuilding the 2.7L engine, but with 2 small kids it will take time. (Can I teach my 2-year-old daughter the difference between a 12 and 13 mm socket?) Rebuilding the 2.7 will probably cost less than the 3.2 if I do the rebuild myself, but how much less? To save money, I'd keep the Webers. Finally, will the heavier 3.2L even be noticeable in terms of handling?

    My car has been modified enough where originality is no longer an issue. It's essentially an Rgruppe car. I've studied Bruce and Wayne's books, but the only P-car I've driven is my '70, so it's hard to imagine differences in performance. I'm asking for opinions here based on personal experience. Thanks.
    Charlie
    '66 912
    '50 VW Bug
    '89 VW syncro Tristar Doka
    '83 VW Westfalia

  2. #2
    I've been contemplating the same thing since I'm also rebuilding my engine. Here's my logic.

    I could buy a used engine with X miles on it and get 100 or 150 -X miles out of it or I could rebuild my existing engine and get 100 or 150 miles. I would know the history of my own engine since I rebuilt it. I'd make less HP with the rebuilt engine but it will last longer than if I bought a used engine.


    Going on that logic I'm rebuilding my 2.4T to E specs. You have a great starting point for a really nice engine that would make alot more HP than stock. Since you've got webers already and its a 74 with the nice Heat exchangers I would rebuild your own engine. With S cams and some JE pistons at 9.5 or 9.8:1 you should be making between 210 and 230. That's about as much horsepower as a 3.2 if I remember correctly. Granted you won't have as much torque but you'll still have that early car feel and it will look right when you open up the engine lid.

    As for $$ I'm looking at about a $4000 rebuild but that includes some upgrades (cams, MFI pump etc). A basic rebuild costs about $3-5K DIY and assuming your pistons and cylinders are still good. If your pistons aren't good any more but your cylinders are (nikasil cylinders are known for their longevity) JE's would be a great route to go. The engine that I described about would be about an extra $1300 or $2000 more than a stock rebuild and you will be making alot more HP than your current setup. Also consiter this. If you buy the 80K mile 3.2 how long is it going to last before it gives up the ghost as well and needs a rebuild?

    Sorry about the length but I'm in the middle of this right now
    Tim
    1973 T

  3. #3
    I went through this a few years back and opted for the 3.2. It had 88k on the motor when we installed it and now has 110k, mostly track miles. Put new valves in 3 heads as i miss shifted. Did 5 track events with bent valves before my mechanic finally heard the motor and said something wasn't right. Other than that no problems. I recently added a custom chip, SSI and a home made sport muffler. With the current rage being 3.6's I see 3.2's going for $5500-$6500. For reliability I prefer a nice stock motor over a tweaked 2.4 or 2.7. Last year I had my 2.4S motor rebuild (another miss shift) I dropped the motor, disassembled it and dropped it off at Jerry Woods. The p&c were new so he just cleaned them up. Parts & labor $9400 (labor was $2500). Add to that mfi rebuild $800, throttle body rebuild $600. The 3.2 pulls in a way the 2.4 doesn't. The 2.4 has a wonderfull whine the 3.2 doesn't. I think the 3.2 is definetely a less expensive route.
    '73 targa w/3.2 track/street car
    '73 S coupe
    '68 v.w. crewcab w/carbureted 2.4E & 5 speed.

  4. #4
    Junior Member
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    Dec 2002
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    Once you experience the torque and docile behavior of the Motronic cars you'll never want to go back.

    Also consider, which would be more desireable a rebuilt 3.2 or rebuilt 2.7, always keep the ultimate goal in sight. Then figure out how to paty for it.

  5. #5
    You can get 3.6 motors for $6000 these days. Installing is another matter though.
    Bobby
    71' Olive 2.2E Targa / Early S #491

    I've always considered the glass to be half full...that is until I reached middle age and realized that it is actually half empty.

  6. #6
    Senior Member
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    Oct 2002
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    Cosley,

    Quick question. If the p&c were good, how did the parts come up to ~$6900? The labor seems really reasonable.
    Neil
    '73 911S targa

  7. #7
    parts $2717.00, machining $3622.00, labor to assemble $2550.00, tax $249.00, total $9138. I disassembled the motor and delivered it in boxes.

  8. #8
    Slow In...fast Out RSupdate's Avatar
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    3.2 vs. 2.7...

    Hi guys, I'll jump right in here and say that I've got a '73E with a chipped 3.2 w. SSI's and K&N cone filter.

    Carbs are almost always going to yeild you more HP as opposed to a FI motor with the same displacement.

    I figure with the hp/torque of my DME 3.2 I'm on par with a good carbed 2.7 RS spec motor.....but with considerably less fiddling of the fuel delivery to get running right.
    Johnny Riz
    73E euro 3.2 w. a few goodies
    Rgrp 152
    S Reg 335

  9. #9
    Carbs are almost always going to yeild you more HP as opposed to a FI motor with the same displacement
    I'm going to have to disagree with this one. A well setup FI system will have a few extra HP compared with carbs. What carbs have that most STOCK FI has is individual runners and it "automaps" making it very flexible to changes in the motor, but FI has the gas under high pressure helping atomazation and it meters the gas much easier than carbs. Porsche never used carbs after about 71 in their racing motors because they could get more HP out of the same displacment motor.

    Granted it could take dyno time and more tuning than carbs but in the end for ultimate HP FI is the way to go.
    Tim
    1973 T

  10. #10
    Slow In...fast Out RSupdate's Avatar
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    In my quest to learn more.... I just wonder why out at the track I seem to notice that all the hot early cars (RS & RSR replica's for example...) are running MFI w. carbs as opposed to motors w. FI?

    I am I missing something ? or perhaps I just missing it all together...?
    Johnny Riz
    73E euro 3.2 w. a few goodies
    Rgrp 152
    S Reg 335

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