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Thread: 2.2E Mild Upgrade. Short stroke or long? Opinions Please!

  1. #21
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    Thanks. The paint is 6603 Early Gulf Blue. The car was originally a paint to sample car. Depending on the light conditions it can look as light as pastel blue or as dark as something approaching Oxford blue only without the purple in the paint. I like it a lot.

    Hey Scott K. When you say 2.7S heads are great for this application, do you mean '74-'77S heads? I haven't checked them out figuring they were detuned from the earlier engines. Am I also taking a chance with any old 2.7S head? I've read that these engines ran much hotter with the rudimentary emission control systems they had in place at the time. I've been told to be cautious about using an engine case but I'm not sure if this advice would also carry over to the heads is they were affected by the heat in the same way. I guess not since the cases were all magnesium while the heads were aluminum.

    An external oil cooler... I was kind of hoping that I wouldn't have to go down that route on account of where I live - it never gets much above 80 degrees here in the summer. It's good insurance I know though.

    I dug out an electronic copy of the workshop manual for early 911's hoping to find out what the measurements of the heads were on the E and S (cc size, int/exh size, ports, cam duration/timing etc). Oddly, although the manual contains a staggering amount of data, the only numeric data they listed about the head & cams was for the cam timing. For those interested this is what it says:
    Valve timing for the E-spec cam: inlet opens 38 deg. BTC & closes at 50 deg. ABC. Exhaust opens 40 deg. BBC and closes 6 deg. ATC.
    Valve timing for the S-spec cam: inlet opens 38 deg. BTC & closes at 50 deg. ABC. Exhaust opens at 40 deg. BBC and closes 20 deg. ATC.
    Only the exhaust stays open longer for the S-spec. I was surprised that that was the only difference.

    I found intake and exhaust port sizes: T 30mm, E 32mm, S 36mm. Scott K, I can see why the 35mm port size of the 2.7S looks so appealing now.

    Does anyone know what the cc size is of the 2.2E/S head? Also does anyone know what the measurements are for the intake and exhaust valves?

    Thanks everyone once again for all the advice and direction.
    Marc C.
    1970E

  2. #22
    Scope Creep Poster Child
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    Marc-

    Two important references would be very valuable to you. Dempsey's How to Rebuild and Modify Porsche 911 Engines 1965-1989 and Anderson's Porsche 911 Peformance Handbook. Look for the latest edition of Anderson's book, as the editing of earlier editions is terrible. These books list all of the specs you're asking about, as well as tons of other information I think you'd find both interesting and useful.

    Keep in mind that MFI injectors are installed in heads. If you use 2.7 heads you will have to modify them to accept MFI injectors. It costs about $700 to have heads ported, so you will have to weigh the advantages of porting your E heads or buying others. Also, you will have to enlarge your MFI throttle bodies. These throttle bodies are usually worn out anyway, resulting in air passing between the throttle shafts and their bores, which results in a high idle speed and noise from the throttle plates slamming up and down in the worn bores. If you are having the TBs rebuilt, enlarging them at the same time is a nominal expense. This means, of course, that you have to have the magnesium throttle stacks enlarged also, and will need larger velocity stacks to match.

    Welcome to the slippery slope! While you're there, let me throw out another idea: twin plug this motor. You'll end up with more power, better driveability, reduced emissions, reduced fuel consumption, and a safer, longer lasting motor. Plus, the undeniably cool sight of a distributor cap with 14 leads sprouting from the top. I'd put this ahead of S cams/space cam any day as an upgrade, and twin plug is at the top of my list for future motor improvements on my car.

    As for the case, it is true that cars with thermal reactors were hard on their cases. However, not all 7R cases were associated with thermal reactors. the 2.4 cases didn't have them, nor did the last of the 7Rs (1977 MY). Of course, the 2.4 cases would need to have their spigots enlarged. In any event, it seems odd logic to use a weak case that needs a bunch of modification to avoid a strong case that may or may not have been affected by a thermal reactor.
    Last edited by Scott Clarke; 09-01-2011 at 09:26 AM.
    Early S Registry 1047
    ’15 VW GTI
    '70 911E, Sold

    '56 Cliff May Prefab

  3. #23
    I think you meant reduced fuel consumption wrt twin plugs, or improved fuel economy.
    1971 911S, 2.7RS spec MFI engine, suspension mods, lightened
    Early 911S Registry Member #425

  4. #24
    Scope Creep Poster Child
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    Thanks, Max. Correction made above.
    Early S Registry 1047
    ’15 VW GTI
    '70 911E, Sold

    '56 Cliff May Prefab

  5. #25
    I agree on the twin plug. You can get the plug hole cut now and wait til later for the expensive distributor solutions. As gasoline gets worse and worse you will want twin ignition to be able to make the most of it. By burning the fuel faster you get better efficiency due to less negative work as the burning mixture pushes down on the still rising piston (which is what happens when you have ignition timing advanced before tdc). More power at no cost in increased fuel consumption.
    1971 911S, 2.7RS spec MFI engine, suspension mods, lightened
    Early 911S Registry Member #425

  6. #26
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    Early Gulf Blue, Nice color.

    Yes, I meant 74-77 2.7S heads. Adding an MFI injector is ~$30 per head. Porting is ~$120 per head. I would rather start with heads with good ports and add MFI injectors than the other way around. I don't think you are 'taking a chance' per sé with 2.7S heads. Most didn't have thermal reactors, actually, and I don't even know/think it makes a difference. Just find a set of heads that hasn't been ported/modified, flycut down too far, the valve seats cut down too far. Also find them without broken fins or corroded/pitted chambers.

    Approx V. of a 2.2/2.4 head is 74 cc, valves are 46/40mm .

    I think twin plug is as great as the next guy does. Adding a spark plug hole is fine, because that's cheap and you can always add a twin plug distributor later. However, to really take advantage of twin plug you want more compression. That's the real advantage of twin plugs. That means changing pistons later. Of course it's nice to have twin plugs, but is it $3k-nice? That's what it costs once you've added double spark plug wires, double CDI boxes, and a 12-pot distributor, NOT accounting for your time. If your budget is unlimited, go for it. If not - spend the money on changing your gears in the transmission, if not upgrading your suspension... especially if you have stock 1970 gearing, twin plug is MUCH less exciting than good gears...

    Also - I don't know why there is an idea that gas is crap. Yes - gas has become more diluted with ethanol - but ethanol is actually a tremendous octane booster; it is 105-108 octane. The problem I guess is that it is hygroscopic and attracts water, which will F up your fuel system if you don't exercise the car regularly, or run a little marvel mystery oil through the fuel system relatively often. However, I don't think gas octane is poised to fall off a cliff, and necessitate twin plugs. . . Open to your thoughts on this one!
    scott kinder
    kindersport@gmail.com

    Registry #614

    9110220587 - 1973 RSR revival in progress
    My Car Thread: "Five-Eighty-Seven..."
    “If it isn't there, it didn't cost anything, it doesn't weigh anything and can't break." - From the philosophy of Grady Clay

  7. #27
    Slightly off topic but I agree with Scott about octane but can only speak of Australian and European trends. With tougher emission rules, engine design is having to change/advance and along side this fuel standards and octane are improving. You can't have modern, efficient, clean engines and run crap fuel. Higher octane fuel means more refining and or additives which means higher price. This becomes politically sensitive and also has impacts on car sales. Its harder to sell a car that needs higher grade fuel but generally it seems most of the industry is moving towards higher octane fuel.

    One point about ethanol, it bumps RON but not MON and MON is related to high speed detonation and is often inaudible but does lots of damage. RON is related to low speed, high load detonation and results in the very familiar metallic rattle we all hear when people are too lazy to downshift.
    Jeff Eelkema
    69E (project)
    S Reg #1431
    Aust TYP 901 #132

  8. #28
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    I’d imagine that I could find these [books] at Wilkinson’s here in town. Good excuse to stop in this weekend. Thanks Scott, I’ve seen both of those books referenced elsewhere on other threads.

    As for twin plugs… those make me drool in the same way whenever Homer Simpson thinks of beer. However for me this sounds a lot like overkill. Yes, drilling the holes and plugging them is inexpensive and I am still dealing with a non-numbers matching case but I think it’s best to try and keep things simple while still keeping it interesting. Our gas up here in the great white north is not as bad as what I heard they put in the go-go juice in sunny CA. We have some ethanol but the percentage is much smaller and you can actually still get gas without it.

    Twin sparks takes me a little too far down that slippery slope right now than I’m willing to go/spend. My intention for this motor is to be street-only but have something that boosts the hp and torque over a stock 2.2E by 15% but try and do this without moving the power and torque curves too much more to the right of the graph while keeping the rev-hapy nature that is a SS engine – a tall order but not impossible. Upping the displacement by putting in 90mm piston/cylinders probably gets me most of the way there. Now all I have to do is decide on what elements do I want that are the best compromise between E and S/RS spec. I’d like to see a little more flow than stock E ports but I still want to try and “manage” any changes and try to keep the power curve from jumping to the right – esp. in the mid-range.

    As for the 7R case, I’m looking in on the case issue.

    Lastly for tonight – comments about spending $’s on other things like suspension as has been suggested. For now I am interested in trying out the stock settings. I’m not too young not to remember how an old car goes. Most of the fun is how these cars put a smile on your face while traveling a sane velocities. I’m happy to charge through corners more slowly. If it means my new Honda can corner faster than my 40 year old Porsche, so be it. We could all have decided to take the money that we’ve poured into these cars over the years and bought a modern 911 if all we wanted to do is go faster but we chose the more colorful character of an older 911. Suspension upgrades are mainly all about getting a mass to change direction faster. To have the same amount of fun/challenge with a Porsche that corners more flatly, you need to be going faster. The engine upgrade isn’t so I can carry more speed through the turns, it’s so I can get down that straight a little faster for that next turn. The brakes are more than capable of handling the small bump in power. IF I was planning to take to the track, it would be a different story and yes after an afternoon of feeling like a boat captain, those suspension, LSD & brake mods would be coming fast and furious. For now, though, I’m happy to keep it stock… okay maybe just a small lowering but that’s just for looks. Lol.

    Thanks again. I have now had a much more intelligent discussion with the people who are working on my motor. There's still a lot to be discssed but I’m feeling much more comfortable that the direction I’m going with the mods will net me the desired result. I guess I have a whole bunch of reading to do now before it’s all said and done.

    P.S. That ESSES magazine is great. I don't know why I took so long in becoming a paid member. The magazine is worth the price alone.
    Marc C.
    1970E

  9. #29
    Senior Member aporschaguy's Avatar
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    Hi Marc, I just built a 2.5 LS with S ports, E cams, JE HC pistons and MFI . I live in North Van and I'm happy to tell you who to use for engine machining etc. I put the motor in a few weeks ago and need to hookup my dual MSDs for twin plug and hopefully enjoy good driving weather for the balance of Sept. You car looks great. We should go for a drive when you get her on the road.

    "He has all the virtues I dislike and none of the vices I admire."

    1971 911e
    1978 911sc Targa (Sold)
    1973 911 RSR (Clone)

  10. #30
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    Just for the record, twin plugs (and more compression) won't move the power curve up. That is, again, what the cam choice does.

    First, select how you are going to drive the car. (Be honest.)

    Secondly, choose cams to maximize your performance there. A billion hp at 8000rpm may mean less to you than 80@2500.

    Then, select everything else to make the combination work.

    aporschaguy's combination is a good choice for you, I suspect. Maybe he would even take you for a ride before you lay down the $.

    Twin Plugs rock. Not saying otherwise. But $/fun ratio is lower on TP than for some other things, like gears. [I would harp on suspension again but stock is fine and you want the original feel.] You clearly want more power (otherwise you would not be having this thread), and gears can feel exactly like more power - you just didn't have to modify the engine to get that. As a rule, a hp gained from gearing is probably about half the cost of the same hp gained with the engine.

    It's funny how these cars require a philosophy of life. . . You want to feel how it was, softly sprung and all, and I don't quite understand that without wanting more stick (tire), or suspension. I just drove a 356 and while it was great fun in its stock (BT6-Super 90 spec.) form, I really don't want to carry that philosophy over to my 911 .

    Just make sure you have fun !
    scott kinder
    kindersport@gmail.com

    Registry #614

    9110220587 - 1973 RSR revival in progress
    My Car Thread: "Five-Eighty-Seven..."
    “If it isn't there, it didn't cost anything, it doesn't weigh anything and can't break." - From the philosophy of Grady Clay

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