Author Topic: Ignition/FIP Timing  (Read 2902 times)

jcochran@cox.net

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Ignition/FIP Timing
« on: August 22, 2014, 02:44:03 »
Hi,
 When I received my recently restored 250SL I was not satisfied with the performance of the engine so I turned to this site (and others) for help and you guys/gals have been incredible in your level of knowledge/expertise and I really appreciate your help . The car is running 100% better now however to achieve satisfactory performance the ignition timing has to be advanced 20-30 degrees. The engine does not knock, accelerates well and has good driveability when advanced. Factory specs. are 8 degrees w/o vacuum so I am concerned as to why my car runs so well so far out of spec. Because the engine runs so smoothly I fell that mechanically the timing is correct which leads me to wonder if the FIP timing could be at the root of the problem. The F/A ratio is good, dwell angle is good, idling is good, etc. If I set the timing back to specs. the engine misses, has poor acceleration, etc. There is probably a simple explanation for this but I really would appreciate any advice or ideas that you can share.

Thanks,
Jim Cochran

ja17

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Re: Ignition/FIP Timing
« Reply #1 on: August 22, 2014, 14:22:12 »
Hello Jim,

Set the timing at 3,000 rpms. first 30 to 38 BTDC seems to be "the sweet spot"  and should be close to spec.  Idle timing is less critical. Many different mal-functions in the distributor can cause idle timing to be off. 
Joe Alexander
Blacklick, Ohio
1969 Dark Olive 280SL
2002 ML55 AMG (tow vehicle)
2002 SLK32 AMG (350 hp)
1982 300TD Wagon turbo 4spd.
1963 404 Mercedes Unimog (Swedish Army)
1989 flu419 Mercedes Unimog (US Army)
1998 E430
1974 450SLC Rally
1965 220SE Finback

ctaylor738

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Re: Ignition/FIP Timing
« Reply #2 on: August 22, 2014, 16:29:29 »
Here is a very simple way to check the pump timing w/o removing the pump:

http://www.sl113.org/forums/index.php?topic=16056.0
Chuck Taylor
1963 230SL #00133
1970 280SL #13027 (restored and sold)
1966 230SL #15274 (sold)
1970 280SL #14076 (sold)
Falls Church VA