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Join Date: Feb 2003
Location: Bay Area, CA.
Posts: 2,048
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Distributor recurving?
I am rebuilding my engine 2.7....
specs: Elgin MOD S cams JE 9:8 pistons PMO carbs 40 What should I recurve my distributor to = just S specs...? thanks |
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02-26-2007, 12:54 PM
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I'd use 2.4 specs or 2.7 RS specs. Basically you want 35 degrees advance total and somewhere around TDC at idle. All 2.4 dizzy's had the same advance. RS is close to what the 2.4 was. I like to see full advance by about 4000RPM.
-Andy
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72 Carrera RS replica, Spec 911 racer |
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02-26-2007, 06:53 PM
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Try not, Do or Do not
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35 degrees @ 4000 rpm with 9.8 compression is a formula for detonation.
That advise needs rethinking when the quality of today's fuel is considered. 4-7 @idle 18-20 @ 2000 28-30 @ 4800 max torque? 32-34 @ 6000 Easy? no, but this would be a fairly nice goal.
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Henry Schmidt SUPERTEC PERFORMANCE Ph: 760-728-3062 Email: supertec1@earthlink.net |
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02-26-2007, 07:39 PM
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Thanks for the correction Henry. I should have noticed the high compression and made a disclaimer that I'm not an expert at the advance curves.
-Andy
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72 Carrera RS replica, Spec 911 racer |
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02-27-2007, 06:07 PM
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Thanks for all the advise
I have decided to change pistons to JE 9:5 to be on the safer side, cause it is true fuel octane may not be high enough.... so what would be the degree? |
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02-27-2007, 06:13 PM
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Henry gave you a nice curve in the above post. The main thing is to not exceed 35 degrees at any RPM.
-Andy
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72 Carrera RS replica, Spec 911 racer |
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02-28-2007, 04:42 PM
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'74 Carrera stock distributor... will it need recurving...?
or is it best to install everyhting first then have it recurve when needed? not sure what specs are on the stock bosch distibutor... new engine being rebuilt specs: PMO carbs Elgin Mod S cams JE 9:5 Last edited by jtkkz; 03-21-2007 at 01:29 PM.. |
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03-21-2007, 12:50 PM
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Porsche Junky
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My plan for the PMO's is to go with the MSD 8981, stake my dizzie and program my curve.....
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1986 930 RUF equipped Last edited by mede8er; 03-21-2007 at 01:34 PM.. |
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03-21-2007, 01:31 PM
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Less brakes, more gas!
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Quote:
Best regards, Michael
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 Michael '82 Euro SC 'Track Rat' 22/29 Hollows, 22/22 Tarrets, Full ERPB F/R, Rennline Tri Brace, Glass bumpers, Pro 2000's, 5 pts, blah blah blah '13 Cayenne GTS |
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03-22-2007, 07:06 AM
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Porsche Junky
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Quote:
In this case however, I'll settle on a maximum advance figure (somewhere between 30-35 depending on A/F) mechanically limit the advance to that degree, then program the MSD curve up to that limit.....
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1986 930 RUF equipped |
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03-22-2007, 08:48 AM
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Location: Sydney, Australia
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I use an MSD 8981, with my distributor welded in the original full advance position.
The only problem is that the MSD gives a maximum 20 degrees programmable advance, so I run about 10 degrees at idle, ensuring I have 30 degrees total advance. I really like the consistency and reliability of the MSD computer/CDI box combination. Craig H |
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03-22-2007, 05:25 PM
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Porsche
Retor 911
Scarab
Riley
1982 Porsche 911 SC 3.6 L
914 2.0
944 Turbo
1986 Porsche 930
Ugly Betty
