Pagoda SL Group

W113 Pagoda SL Group => Drive train, fuel, suspension, steering & brakes => Topic started by: Dave on September 28, 2013, 13:56:46

Title: bosch red coil how many ohms?
Post by: Dave on September 28, 2013, 13:56:46
Anyone know?  It is actually brand new with red label
Title: Re: bosch red coil how many ohms?
Post by: 280sl1968 on September 28, 2013, 18:00:27
Needs a separate 1.8 ohm ballast resistor.

David
Title: Re: bosch red coil how many ohms?
Post by: Benz Dr. on September 28, 2013, 20:17:14
The black coil is about 13 KV and the red one is about 26KV.  So, following simple math, the black coil uses .9 ohm ballast resistor and the red coil which is twice the voltage, uses twice the resistance on the ballast resistor at 1.8 ohms.
Title: Re: bosch red coil how many ohms?
Post by: Dave on September 28, 2013, 23:32:29
The car now runs great thanks to you and others who helped me get the timing right.  Just got back from 45 minute test drive - wow!  I can't figure out if the ballast resistor should left on.  It runs great with it on now but i dont know if i should take it off.  051 distributor red coil 1.9 resistor
Title: Re: bosch red coil how many ohms?
Post by: Benz Dr. on September 29, 2013, 15:02:40
If you have the orginal point set up you better leave the resistor in place or it will damage the points and can damage the coil if the ignition is left on.
Title: Re: bosch red coil how many ohms?
Post by: Dave on September 29, 2013, 17:00:44
Newly installed pentronix thats why i dont know if resistor should be used  or  bypassed
Title: Re: bosch red coil how many ohms?
Post by: Benz Dr. on September 30, 2013, 14:48:25
OK, in that case you may not need it.  The ballast resistor lowers primary voltage going into the coil and across the points.
Title: Re: bosch red coil how many ohms?
Post by: rogerh113 on September 30, 2013, 15:48:18
Again, I've been using my Pertronix for over a decade with the ballast resistor in place, and never had any issues.  With a red coil, if anything you would require a resistor with higher ohms. 

It sounds like your car is running great and you are pleased with the performance.  What do you figure the downside is of leaving the resistor in place??   With the car running well, I would be more concerned about removing the resistor.  A really nice thing about Mercedes, particularly the older ones, is once you fix it you generally don't need to keep poking at it.  Generally that does not make things better, although it may provide entertainment value.  Maybe a good time to move on to something else on the car that needs attention and just monitor the performance.  My guess is that the Pertronix will just keep humming along with no troubles. 

Regards -- Roger
Title: Re: bosch red coil how many ohms?
Post by: 1mastertech on October 03, 2013, 03:41:25
Across the primary side of the coil, terminals 1 to 15, measures 1.5 ohm.  I have 2 new 'red' coils on the shelf and I measured them both.  The same.   This coil has Bosch number 0 221 119 030 and Mercedes number 000 158 49 03.   Terminal 4, the secondary circuit, to either terminal 1 or 4 is open.  Don't understand where the 27K ohm primary circuit reading in an earlier post came from.  Did I misunderstand the question?
Title: Re: bosch red coil how many ohms?
Post by: Peter van Es on October 03, 2013, 07:06:19
26KV not 27 K Ohm...
Title: Re: bosch red coil how many ohms?
Post by: Benz Dr. on October 04, 2013, 03:35:31
26KV not 27 K Ohm...


Right.  The red coil produces roughly 26KV ( kilo-volts ) or 26,000 volts. There is little amperage in a 12 volt ignition system so that's why it will normally only hurt and not kill you. :o If you happen to have pace maker for your heart or heart trouble, you should stay away from ignition systems.
Title: Re: bosch red coil how many ohms?
Post by: dante53 on October 04, 2013, 20:48:52
My new Bosch red coil measured 1.4 ohms