w111 3.5 pertronix/dizzy
 

Hi all,

I am having trouble locking down the correct petronix ignitor module for my '71 3.5 280se w111 coupe. I don't have the dizzy number to put into their system..does anyone either have said dizzy number or the pertronix part no. for my car? Thanks.

Dave

Safest bet is to get the numbers from the distributor housing. Any numbers from the VIN will tell you what was originally in the car. In 40+ years it is possible the dist. was changed/replaced.

Thanks Mike.

Good point. I shall wrestle with it until it gives up its secrets.

d

If original, it would depend on whether Euro or NA car. Shop manual for M116/7 engines lists several distributors (6, I think I saw ) as does the Technical Data Manual.

For early 4.5L V-8s, the Pertronix 1885 (Ignitor) is the one we use and is listed in the Pertronix catalog for the 72 280SE. Not the Ignitor II if original type solid core wires are used.

The distributor number is on the casing. Might be a bit hard to see it without removing distributor.

Thanks all. I took the dizzy out to see the part number, it is 0-231-302-001.
Reading on here, that is the European version, which makes sense. The US version is 0-231-302-002, which has an exhaust emission control, whatever that is.
Pertronix do not list anything for my part number, although there are many very close matches. I have asked Pertronix, am awaiting a reply…I was wondering whether anyone on here had any suggestions in the meantime?

Thanks.

Dave

Consider checking the ignition points part nos. If same points are used in 4.5 & 3.5, then it is likely that the same Pertronix unit is used.

I imagine the advance/retard characteristics are different for the 3.5 Euro and 4.5 NA engines. But not sure if that makes any difference to Pertronix choice.

Best to wait and see what Pertronix say. They do sell Pertronix in Europe. Contacting their Euro distributor might be a way to approach this because Pertronix USA may not be familiar with your distributor.

Cheers Frank. Good idea. Looking at the Pertronix catalogue, they supply just 2 modules for the 8 cylinder cars, 91884 and 91885. The former is for a dual point dizzy, which mine is not. The latter is for the 1970 600 model, '72 280se,sel,300sec and 350sl, and the '73 450sel. I think there is a good chance that one will fit, but I'd like a definitive answer from Pertronix before I commit.

d

91885 is the Pertonix II which even Pertronix say not to use with the solid core copper ignition wires our cars use.
1885 is the one we use.
But I already said that in an earlier post :rolleyes:

So you did Graham. Mea Culpa. I have suppression core wires anyway. Looks like 1885/91885 then hopefully.
d

What type of wires are those?

I use Bosch 09027 copper core wires (~1kohm). Others go to lengths to try and obtain OE type copper core wires with resistors both ends (6.5kohm?)such as those that were made by Beru. Don't hear of too many abandoning copper cores.

What it says on Bosch box and what some ads like this one from Amazon say, is incorrect for these wires. That particular 09027 model of Bosch wire actually has a copper core, and with resistor at just one end. The wires themselves say "Bosch 7-MM Opti-Layer Copper Core Ultra-Premium". Why they put them in the generic boxes beats me.

Pertronix apparently say that their units can fail with copper core wires. Even the Ignitor, but less so with it than with the Ignitor II, which has more susceptible electronics. Failure is apparently thought to be caused by voltage spikes when wires short to ground (presumably they think that is more likely with copper cores?)

I have these on there presently. I would be pleased to hear if they are a bad idea ( wouldn't be surprised, I'm learning every day here). They fit fine and work fine on other contact point ignition systems. I like the idea of not being able to fry the ignitor II if I leave the ignition on, but I am happy to swap to the ones you point out and go with the original ignitor if needs be.
Thanks,

d

No idea about those leads. What led you to buying Lucas Range Rover ignition wires for your vintage Mercedes? Surprised that the lengths would match.

The fact that I needed some quickly and that they were available locally for not much money. When you look at the layout and displacement of the 3.5 rover engine it seemed as though they would fit, and they do. I may well move over to the Bosch ones if needs be however.

d