Author Topic: Does any one know the 280 sl standard rpm when engin is idling in a normal tempe  (Read 5253 times)

yehsf2003

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Hi Masters,

It seems to high in my 69 280 sl that the idling RPM is 1050-1150. Does any one know the 280 sl standard rmp when engin is idling in a normal temperature?

Thanks

Frank

Surfer65sl

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Your idle can be adjusted below 1100 to 1000....For my manual it sometimes auto idles higher until warmed up properly but by revving engine it then will adjust lower to around 1000 rpm's, which feels just about perfect.

Good luck with it.

Matt


J. Huber

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Frank, from your post, it is not clear whether you have an automatic or a manual. In either case, I think the idle should be lower -- around 700-750 I think. Mine likes 800-850 in Park -- so I'd say, the final number is not so important as a consistent purr.
James
63 230SL

Garry

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Mines a manual and is happy to sit at idle around 650-700 rpm. !000 appears too high if it s a manual.
Garry Marks
Melbourne/ Kyneton, Brisbane. Australia
1969 MB 280SL 5 speed RHD SOLD.
1965 MB 230SL Auto RHD Lt Blue 334G, Top 350H, Tourist Delivery.
1972 MB 280CE Auto RHD 906G
2005 MB A200
2006 MB B200
2019 Izuzu DMax 4x4 Slide-on camper.
2022 Volvo XC40 Electric
2024 Volvo EX30 Electric

Cees Klumper

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I think normal is 750-800 and I would suppose it should make no difference manual or automatic. In idle why would there be a difference, and in gear the automatics have the constant speed solenoid to compensate for the drag.
Cees Klumper
1969 Mercedes 280 SL automatic
1968 Ford Mustang 302 V8
1961 Alfa Romeo Giulietta Sprint Coupe 1600
1962 FIAT 1500S OSCA convertible
1972 Lancia Fulvia Coupe 1.3
1983 Porsche 944 2.5
1990 Ford Bronco II

hauser

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What needs to be done to lower it?

Tom

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Hauser,

Lowering the idle should be done with a complete review of the linkages, air/fuel mix,  a check of the timing/advance, etc.  You can lower the RPM a couple of different ways (like just backing off the air coming through the air intake-a simple turn of a screw driver), but could hurt the performance in another way.  So not an easy answer.

Best,

Tom
1971 280sl Tunis Beige Metallic

SteveK

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800 is the number I've seen in most places.  I would think a little higher for the automatic where there is a little higher resistance due to more things to spin.  If you have AC you might also want an extra 50 RPM's to keep everthing steady.   I have a standard with no AC and I adjust to around 700 (it just sounds good there to me).  I use the screw on the throttle body to adjust between summer and winter, which I suspect may be a slippery slope.  Doing it by linkage would be best to make sure eveything stays in sync.
« Last Edit: November 21, 2010, 03:31:07 by SteveK »