1972 W108 280SE 4.5 Petronix II wiring

[Scotto52]

I’ve was asked to post how I installed my Petronix II. It was very simple, I just had to do some research. The schematic is straight from Petronix. I’m using my original coil. And I put new spark plug wires on that are not solid core.

Schematics
https://i.imgur.com/uQKguj4.png
https://i.imgur.com/MHAG8Il.png

Pics
https://i.imgur.com/kMknBes.jpg
https://i.imgur.com/sUbcFqK.jpg

This guy’s video was also helpful.

https://youtu.be/eP6IcCe7vpU

The resistor is the lower blue one on the L/F on the frame. The vehicle was not running properly prior to this install, so I can’t really say how good it’s performing. But it runs really good, no hesitation or anything. Petronix also said in my email that the II will not burn out the coil with the key on and is ok to jump start.

[Graham]

Originally Posted by Scotto52

I’ve was asked to post how I installed my Petronix II. It was very simple, I just had to do some research. The schematic is straight from Petronix. I’m using my original coil. And I put new spark plug wires on that are not solid core.

Your schematic is same as the one I posted on Benzworld 107 forum and likely linked to from here at various times. The link shows the no-bypass schematic plus one for those wanting to bypass the MB switchgear and use a Pertronix coil.

The Pert II has the advantage over the Pert I of being less likely to burn out if the key is left in start position for extended period. However, the apparent need to use non solid core wires with the Pertronix II is often a show stopper for some. Based on experience, we know that the original solid core wires work with the Pert I.

Were you able to buy a wire set made to fit the MB V-8 complete with the correct end fittings? Can you provide a link and/or describe their comstruction?

[Scotto52]

I had to make my own wires. And it was a nightmare. I think they were made by Accel. I could not get the boot over the 90° crimp that I made. I tried silicone spray, dielectric grease and wheel bearing grease to help move the boot over. About 5 connectors got damaged before I was even able to get a good wire completed. I went back to my local auto store and explained my problem. The most they could do was give me a new set of wires to try again. This time, I cut and crimped the wires. I put the wires in heated parts washer that we have at work. I think the temp is set to 180° and the wash cycle is about 10 minutes. As soon as it stopped, I lubed the wires up with Vaseline and was able to slide the boot over the crimp. It was still a struggle though. The wires are all pretty close to the same length. There must be a vehicle out there somewhere that’s almost identical to length.

[Graham]

Originally Posted by Scotto52

I had to make my own wires.
>
There must be a vehicle out there somewhere that’s almost identical to length.

They would also need matching distributor end fitting. I think that fitting changed after the 72 models. Seems difficult to comply with Pertronix wire spec for their Pert II Ignitor. DIY like you did, or maybe someone like Kingsborne or others could make a custom set?