Just wanted to thank everyone for their previous postings about the Pertronix ignition upgrade. I upgraded my 1972 280SE 4.5 this weekend and find it makes an instant improvement. I would comment that the wires from the sensor are very short, so plan on extending them from the beginning. The new coil is smaller than the old Bosch one and is a challenge to fit into the mounting bracket. But all in all, I recommend it highly. Thanks again!

Yes, those wires are short...I called them and told them it would be better to spend the extra $0.05 and let people cut them down rather than make us splice them.

Also, for the coil you can use a section of old radiator hose to wrap around the coil to take up the excess diameter or do what I did and wrap it in duct tape...about 10 turns was enough to get a snug fit. Either way it only take a couple of minutes to remedy that issue.

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Marty D.

2013 C300 4Matic
1984 BMW 733i
2013 Lincoln MKz

I made the conversion awhile back and have been very satisfied with the performance and elimination of the points. I did have two of their Blaster coils fail on me though. The first one started leaking oil from overheating and the second just caused severed missing after a couple of months. Both were 1.5 ohm and I am now running the 3.0 ohm without problems. I eliminated the white resistor block from the original MBZ point setup. Both failures were replaced free of charge without question by Pertronix.

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Gregg:
http://photobucket.com/albums/d142/GBambo/

Pertronix recommends the 1.5 ohm only for 8 cylinder applications. For 4 or 6 cylinders they call for the 3.0 ohm coils...what engine were you running it with, the 6 or 8 cylinder?

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Marty D.

2013 C300 4Matic
1984 BMW 733i
2013 Lincoln MKz

In answer to the questions, I have the original M127.984 134 hp six cylinder engine that came with my 63 111.

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Gregg:
http://photobucket.com/albums/d142/GBambo/

Yeah, they should have told you straight off to use the 3 ohm with the 6 cylinder and not to use any ballast with it. Using the 1.5 is probably what caused them both to fail prematurely.

-Marty

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Marty D.

2013 C300 4Matic
1984 BMW 733i
2013 Lincoln MKz

I have a 1971 280SE 3.5 with the M116 engine. I've no success in getting the Pertronix ignitor to work. The instructions say that you need to
1. remove the points, condensor and the wires attached to them,
2. install the ignitor
3. connect the red wire to the ignition side of the ballast resistor
4. connect the black wire to the negative side of the coil

I did this - no spark.
I then removed an earth lead from the negative pole of the coil.
Still no spark.
Had the ignitor tested for faults - the unit works.
I'd appreciate a wire by wire explanation from someone who has installed one of these successfully on an M116.
As the car runs with points, the problem is definitely related to my installation of the ignitor.
I have a 1.5 OHM Flamethrower coil.

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Alastair
1971 280 SE 3.5
1980 300D
1980 240D (sold to friend - still going strong)
Adelaide, South Australia
http://members.ozemail.com.au/~adow/index.htm

Your problem is using the ballast resistor, I suspect. If you are using the 1.5 ohm flamethrower you don't need the ballast resistors at all, don't use either of them. Simply attach the switched +12V lead from that used to feed the coil's ballast resistor to the (+) post on the flamethrower coil, along with the red lead from the ignitor module. Verify you have the correct +12V lead by checking with a voltmeter with the iginition switched on. There is a +12V lead that is only energized during cranking that is attached to the other end of the coil ballast (that was part of the bosch system)...you don't need to use that one, it was used to boost spark during cranking on the old system...just tape it off.

The black lead from the ignitor module goes to the (-) post on the coil...no other wires are required. If all the parts are good then this should work.

IMPORTANT NOTE ---->> Make sure you re-install the rotor...I have heard from Pertronix that often times people don't realize they still need it and don't put it back in! That represents about 75% of their installation "failures".

I have installed these in two MBs and both worked fine the first time out. I always first test it out by hooking up test leads (with aligator clips on the ends) and start it up to make sure the system is wired right before I solder and splice it all in but the wiring is very simple once you remove all the bosch stuff that you no longer need.

Good luck.

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Marty D.

2013 C300 4Matic
1984 BMW 733i
2013 Lincoln MKz

This all makes sense and checks out with a voltmeter. I would need to extend the switched lead that is presently attached to the coil ballast resistor to reach the + post on the coil but it is possible.

The coil is also earthed from the negative pole. (It is earthed at the same point as a heavy earth wire that comes up from the original ignition system). I'm assuming that you should remove this earth wire from the coil.

So far so good.

However there is a second ballast resistor (0.4 ohm - blue band) lower down and near the original ignition system. This has three wires attached to it. One appears to go back to the original ignition system, and two others, one from each end of the ballast resistor, wind their way back past the battery and into the car body at the firewall. There is no direct connection between the lower and upper ballast resistor.

So, I am still unsure which wire and which ballast resistor you are referring to here -
Thanks again for your assistance.

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Alastair
1971 280 SE 3.5
1980 300D
1980 240D (sold to friend - still going strong)
Adelaide, South Australia
http://members.ozemail.com.au/~adow/index.htm

The other ballast is for the power source of the bosch transistorized ignition module, as I recall. You don't need to use it at all. What I did was left the ballasts installed, disconnected the wire to the old module and removed the old module but left the wires on the other side of that ballast intact...this way if I ever want to go back to the bosch system I could re-install it later. You can do the same with the other ballast too...leave it there, just disconnect the wires you don't need.

If your old coil is presently grounded disconnect that wire, the only wire needed on the negative terminal is the one from the ignitor module. I don't really understand why you would have a ground wire on the negative terminal of your old coil but don't have the wiring diagrams in front of me right now so I can't comment...I just know you don't need anything else when running the pertronix set.

My 4.5 is identical to your 3.5 in terms of the ignition system, so I am very familiar with it. The old bosch system was much more complicated than the Pertronix...when you see how simple the new wiring is, once it works, you will see what I mean.

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Marty D.

2013 C300 4Matic
1984 BMW 733i
2013 Lincoln MKz

<< I don't really understand why you would have a ground wire on the negative terminal of your old coil >>

Second generation [ late]Transistor Ignition switchgear used the positive side of the circuit for coil switching.
Early units used the switched ground.

Well that must explain it...in any event, for the Pertronix setup you don't need to ground the coil, but he would need to make sure the distributor plate is grounded which the ignitor module attaches to if that would be different on that later style.

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Marty D.

2013 C300 4Matic
1984 BMW 733i
2013 Lincoln MKz

The distributor plate is currently grounded with a wire that goes back to the original ignition system - the earth wire is one of two wires that goes from the distributor to the original ignition system, the second being attached to the points. I've been removing both these wires completely when installing the ignitor. Are you suggesting that I leave the ground wire in place?

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Alastair
1971 280 SE 3.5
1980 300D
1980 240D (sold to friend - still going strong)
Adelaide, South Australia
http://members.ozemail.com.au/~adow/index.htm

For the Pertronix system to function the wire which goes to the distributor's plate should be attached to ground (earth). Apparently your old system was slightly different than mine but in order for the Pertronix module to function the plate it attaches to needs to be grounded. Typically that would be the case but it seems your old system was intentionally wired backwards by design. That probably contributed to the problems you were seeing with the ignitor module not working right. That plate in the distributor does need to be grounded to work right. That's how the primary ciruit gets completed through that attachment.

So basically your circuit goes from chassis ground to the distributor plate, through the module and through the black wire coming out of the module to the (-) terminal on the coil for the negative side of the circuit. On the positive side you simply connect the switched +12V wire and the red wire from the ignitor module to the (+) terminal on the coil...then you should be ready to fire it all up. Let's hear some revs!

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Marty D.

2013 C300 4Matic
1984 BMW 733i
2013 Lincoln MKz

There were two versions of the Bosch transistor ignition.

The first version switched the power to the coil, with the coil (-) terminal grounded. The second version used the switch box to ground the coil, so the (-) terminal wire goes to the box. (unless I have that backwards -- I don't have the book handy).

The earlier version was used on the six cylinders and the 3.5L M116, after 1972 all used the later version.

Peter

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1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!