Pagoda SL Group
W113 Pagoda SL Group => Electrical and Instruments => Topic started by: Ulf on October 05, 2015, 17:35:16
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Just noticed that this thing is in a very sorry state - it seems like some kind of bakelite or ceramic relay right behind the battery that is cracked and the wire sticking out seems charred - any idea what this is? Have looked through various diagrams without luck... :-)
Thanx in advance
Ulf
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It's the ballast resistor for the ignition, looks like you need a new one...
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I agree - i looked it up on SLS, but there seems to be several options (ohms) to choose between???
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I agree - i looked it up on SLS, but there seems to be several options (ohms) to choose between???
Depends on what coil you have.
If its the original black coil, you need the 0.9 ohm resistor (looks like thats what you have on your car)
If a 'red' coil is fitted, you need the 1.8 ohm one.
naj
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Thanks - my coil is red, but as I might replace that at the same time, I've asked SLS to provide me with both. Just replaced the one on my 1982 Land Rover SIII and I have never felt a single component give such a huge change :-)
Ulf
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Hi Naj,
This is interesting as when I purchased my car it had 2 ballast resistors fitted in tandem ( can't remember but l think they were both 0.6). I never liked that look so instructed them to replace it with a new one that I bought 0.9.
My car didn't start so well so l then asked them to change back to 2 in tandem and gave them another we 0.9 ballast resistor to fit. So now l have 2 X 0.9. By the way l have the red ignition coil.
It starts better but l feel it was never as good as before. I then read that originally the 280SL came with a 0.6 ballast resistor was contemplating have them try that.
I guess after reading your post l should leave it as is or replace them with a single 1.8ohm ballast resistor?
Appreciate your thoughts?
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Hi Rob - honestly I don't have a clue. Have ordered the resistor only as the coil is currently not in stock, I looks like an easy fit - will keep you posted though...
Ulf
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Hi Naj,
This is interesting as when I purchased my car it had 2 ballast resistors fitted in tandem ( can't remember but l think they were both 0.6). I never liked that look so instructed them to replace it with a new one that I bought 0.9.
My car didn't start so well so l then asked them to change back to 2 in tandem and gave them another we 0.9 ballast resistor to fit. So now l have 2 X 0.9. By the way l have the red ignition coil.
It starts better but l feel it was never as good as before. I then read that originally the 280SL came with a 0.6 ballast resistor was contemplating have them try that.
I guess after reading your post l should leave it as is or replace them with a single 1.8ohm ballast resistor?
Appreciate your thoughts?
Hi, Rob,
The red coil is a replacement for the original black coil.
The red coil should be used with a 1.8 ohm ballast resistor. The original black coil used a 0.9 ohm resistor.
Does your 1970 car use a transistorised ign system? Don't know if the RHD cars ever used them?? The US spec cars did.
The transistorised ign system uses a much stronger coil (originally blue) and used two ballast resistors in series, a 0.6 ohm and a 0.4 ohm. One of the resistors is bypassed during cranking for easier starting. The bypass feed comes from the extra (live when cranking) terminal on the starter.
naj
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Thanks Naj,
This is actually for my 1969 280SL. I know it has a red coil but l am not sure if my ignition systems has been converted.
I will check when l get back from business trip.
It's interesting to hear that some people do have resistors in series as l think mine was the only car l saw with 2.
Thanks
Rob
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Whenever I look for ignition coils from various brands (Valeo, Beru, NGK etc.) on eBay.de - the 250 SL always comes up as the only compatible vehicle...???
Does anyone have the part # for the red Bosch coil mentioned above?
Thanx in advance
Ulf
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Hi,
have you looked for it in the Bosch spare part lists or here: www.bosch-automotive-tradition.com/en/internet/automotive_tradition/wissen_1/wissen_iframe.html ?
...WRe
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... and more
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Does anyone have the part # for the red Bosch coil mentioned above?
Thanx in advance
Ulf
Did you have a look in the Tech Manual?
Bosch # for the red coil is: 0 221 119 030
naj
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Thanx - have just fitted the ballast resistor (and found rampant rust under the battery tray which took a lot longer to treat), there is a new battery on its way and I will see if I can find the coil as well in time for the weekend...
Keep you posted :-)
Ulf
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Thanks Naj,
It's confirmed I do have the red transistorized coil.
I assume I should now fit a single 1.8ohm ballast resistor, or do you think I still need two resistors in series?
Regards
Rob
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Hi, Rob,
Bosch use only one 1.8 ohm resistor with the Red Coil.
naj
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Thanks