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911914
Join Date: Feb 2008
Location: NY
Posts: 27
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Acceleration On Rebuilt Motor
I have been slowly breaking in my 911SC motor and now that I have reved it up to 5000 rpm the acceleration is not a quick prior to the rebuild. Any advice?
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10-31-2008, 01:50 PM
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Registered
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Hey..
I suspect you have not set the timing right...? ( 5 deg. BTDC) If not, check the ignition on each cylinder, cam timing, and so on... |
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10-31-2008, 04:02 PM
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911914
Join Date: Feb 2008
Location: NY
Posts: 27
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Thanks, Would using Bosch platinum cause a problem?
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10-31-2008, 04:08 PM
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Quote:
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10-31-2008, 04:29 PM
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Max Sluiter
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Bosch Platinums are typically too "hot" for old air-cooled Porsche flat-sixes. This can cause detonation due to the heat retained in the cylinder head. Detonation/misfiring can cause poor acceleration.
On the other side, too "cold" of a plug can cause plug fouling, which will cause poor running all over the rev range but can clear up when pushing it hard. It would re-appear at idle. If your engine idles smoothly but is down on power, maybe it is detonation from too hot a plug? The cold ambient temperature would lead to leaner air/fuel ratios...
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1971 911S, 2.7RS spec MFI engine, suspension mods, lightened Suspension by Rebel Racing, Serviced by TLG Auto, Brakes by PMB Performance |
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10-31-2008, 06:43 PM
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Manassas, VA
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Flieger,
I beg to differ. Bosch platinum plugs can be had in a wide variety of heat ranges. Often the platinum type plug is not required but this alone will not change the heat range of the plug. My car came from the factory with Bosch platinum plugs and that is what I currently run. Before you suggest that a plug is "too hot" you would have to know the designation on the plug. If it was a WR9DP0, I might agree with you, assuming a stock engine of course. Transformer, What is the designation of your Bosch platinum plugs? Thanks, Mark
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1991 964 Polar Silver Metallic Turbo Coupe |
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10-31-2008, 07:15 PM
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Wer bremst verliert
Join Date: Jan 2005
Location: Toronto, Ontario
Posts: 4,767
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How about this..what do your plugs look like?
Do you have access to/can you borrow an AFR and check you mixtures?
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2007 911 Turbo - Not a toy 1985 911 Cab - Wife's toy 1982 911 3.2 Indiash Rot Track Supercharged track toy 1978 911 3.0 Lichtbau toy "Gretchen" 1971 911 Targa S backroad toy |
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10-31-2008, 10:24 PM
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Air Medal or two
Join Date: Jul 2003
Location: cross roads
Posts: 14,077
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firing order..............
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D troop 3/5 Air Cav,( Bastard CAV) and 162 Assult Helicopter Co- (Vultures) South of Saigon, U Minh Forest, Delta, and all parts in between |
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11-08-2008, 08:49 PM
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Less brakes, more gas!
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How many miles on the build? Mine was a little slow for a bunch then seemed to kick in around 500 miles... I suspect the rings seated at that point and I'm now getting decent compression. Perhaps your rings have not seated yet?
-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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11-09-2008, 05:18 AM
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Registered
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where in ny are you located?
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1974 sahara beige 911 targa 1982 chiffon 911sc 1985 prussian blue metallic carrera |
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11-09-2008, 07:18 AM
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Black bastard
1971 Porsche 911S
1991 Porsche 964 Turbo 3.3L
Ugly Betty
1974 Porsche 911 targa 2.7
