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Registered
Join Date: Feb 2012
Location: Driftwood, TX
Posts: 8
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2.4 CIS cam options?
I'm rebuilding the top end of my 1973.5 CIS to fix #1 compression issue and oil leaks around the rocker shafts. I'm going to reuse the original P&C and retain the CIS induction system for now.
Looking at Wayne's book, some of the 3.0 SC engines can benefit from a 964cam. So I'm wondering if the 2.4 CIS can benefit from a later 2.7 CIS cam like the 74-77 S/Carrera 911.105.143 & 144. Has anyone tried this? My main concern is that the original 8:1 compression would be further reduced by later intake closure. This car is strictly for street use, so I don't want to lose torque in low rpm range... but sure would be nice to have it push above 5500 rpm! Last edited by 4wdbus; 02-13-2012 at 09:05 PM.. |
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02-12-2012, 09:45 PM
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Registered User
Join Date: Dec 2010
Posts: 71
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Hello Bus,
I am also rebuilding a 73.5 cis motor and was somewhat puzzled when I discovered that the cams in the engine were the 143 and 144 2.7s cams. The car is new to me and I am not sure of the why's or how's of the cams, but I would assume that since they are the closest to the stock cams they work. The car ran before I tore it apart,(low compression and leak down #'s on #1 and #4). Good luck with your project and look forward to reading what others here have to say on the topic. Gib |
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02-13-2012, 06:13 PM
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Registered
Join Date: Oct 2008
Location: Nash County, NC.
Posts: 8,482
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The cams can be upgraded to CIS S cams and set to S spec. Any other cams wont work for your application.
Bruce |
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02-14-2012, 01:40 AM
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Registered
Join Date: Feb 2012
Location: Driftwood, TX
Posts: 8
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Thank you for the guidance
 I found a good set of 77 towers complete with S cams and rockers, so I am probably going to give this a try. Should I expect any torque reduction at low rpm or is this effect negligible? -Van |
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02-14-2012, 07:24 AM
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Registered User
Join Date: Dec 2010
Posts: 71
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Flat6,
Does that mean that when setting the cam timing, one would just use the spec for the 2.7 cam as if it were going into its original engine? I was wondering on my own build what the gauge numbers were for cam timing, but have not gotten that far with it yet. Gib |
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02-14-2012, 07:30 AM
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Registered
Join Date: Feb 2004
Location: California
Posts: 926
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Quote:
Yes, the cam setting spec follows the camshaft.
__________________
John Dougherty Dougherty Racing Cams |
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02-14-2012, 08:40 AM
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| Tags |
| 2.4 , cam , cis |
