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Registered
Join Date: Jun 2001
Location: New Zealand
Posts: 132
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Will 2.2 911T pistons work in a '71 911E?
Will there be any valve to piston clearance issues with E cams?
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Kelvin '67 912 New Zealand |
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05-30-2006, 04:01 AM
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PRO Motorsports
Join Date: Nov 2001
Location: Burbank, CA
Posts: 4,580
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Won't work.
You can have the pockets opened up. You can go just deep enough to clear E cams, or maybe a little more if you machine the pockets by, IIRC, 2.5mm deeper.
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'69 911E coupe' RSR clone-in-progress (retired 911-Spec racer) '72 911T Targa MFI 2.4E spec(Formerly "Scruffy") 2004 GT3 |
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05-30-2006, 03:02 PM
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3 restos WIP = psycho
Join Date: Feb 2005
Location: North of Exit 17
Posts: 7,665
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The compression ratio trade off and the cost of machine work just isn't worth it. If you've driven the 'E' in question, you'd undoubtedly be disappointed by the results.
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- 1965 911 - 1969 911S - 1980 911SC Targa - 1979 930 |
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05-30-2006, 03:54 PM
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Join Date: Mar 2005
Posts: 743
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I agree..do not do it!
You need all the compression you can get..I have tried this combination.. Kind regards David |
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05-31-2006, 12:20 AM
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Stranger on the Internet
Join Date: Apr 2004
Location: Bradenton, FL
Posts: 3,244
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Is this applicable to the 2.4T also? ie, if running "E" cams with 2.4 T pistons, is there just not enough compression ratio to take advantage of the E cam profile? Probably best to find 2.4 E style pistons?
Thanks! Pat
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Patrick E. Keefe 78 SC |
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06-03-2006, 09:08 AM
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up-fixing der car(ma)
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Pat, yes, it is. As you go "hotter" on the cams, I'm sure you're aware that the amount of time that the valves spend open increases. This reduces the effective static pressure at low RPM, and gives you no torque. The 2.4T had about 7.2:1 compression, which is VERY low. Increasing the duration and valve lift will only exacerbate the problem of low compression at low RPM, but at high rpm, it will be more powerful than stock (not a good trade-off, IMHO).
What is a great and reasonable combination is 2.2T pistons/cylinders on a 2.4 crankshaft. You get up to about 9:1 sometimes, this is very good for use with an E cam (like Tyson said). 2.2E and 2.2S pistons produce around 9.4:1 and 10.2:1, respectively, on a 2.4 crank, and about .6 lower if it uses a 2.2 crank. I don't really think I'd use any 2.4 pistons because the compression is so low (2.4E=~7.8:1 stock on the longer-stroke 2.4 crank!) Cheers, Scott
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Scott Kinder kindersport @ gmail.com Last edited by YTNUKLR; 06-03-2006 at 12:02 PM.. |
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06-03-2006, 11:55 AM
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