MSD questions

[project 911]

I'm preparing to install an MSD box and coil on my carbed 2.2. I've been through miles of archives on this but still need some advice.

Details: MSD 6TN with external Soft Touch rev controller. SS coil.



#1. Plug wires- MSD says not to use with solid core wires. I've seen advice both ways on this. I have 7mm Bosch silicone wires. Will these work or do I have to replace them with spiral wound?

#2. Rotor- I've seen several threads about burned rotors with these systems. One suggestion was to go to a solid rotor. I picked up the suggested Echlin EP141 (VW) rotor, but it does not fit my Bosch dizzy. It seems to be made for a tapered shaft. Does anyone know of one that would fit (part number)?

Anyone have a pic or details about soldering a bridge on a stock Bosch rotor?


Wiring this thing could be interesting since I seem to have different color wires than the manual shows. You'll probably be hearing from me later on that...

[aj748]

Added the MSD setup to my 71S a couple of years ago.

1. Wiring the unit is pretty straight forward. The importance of "robust" power and ground connections to make this setup work right and last a long time cannot be overemphasized.

2. You can add the recommended ignition wires later. I used the stock wires to get everything running, then switched over to a set of Jacobs wires. Use these wires with plenty of silicone grease in the boots if you ever want to get them off the plugs!

3. I also used the stock rev-limiting rotor but soldered heavy gauge buswire across the resistor. Again, clean connections make sure you do not create a cold solder joint.

4. Getting the tach to work may was my biggest challenge. Make sure you have continuity from the engine compartment to the tach signal wire.

5. I was able to open up my plug gap to 0.040 in. with this setup.

Plenty of info and diagrams posted on this previously here. Go slow and document your changes in case you need to backtrack. Best of luck!

Andy

'71 S
'88 M3
'99 748

[project 911]

Thanks for the info Andy.
So far I think I've collected every diagram and description ever posted here. Seems like the tach thing depends on what year tach you have. Some people report it working with no tach adaptor, others report no tach even with the adaptor. Guess I'll have to wait and see with that.

I got a used MSD box, and it seems to have wires (like pink) that aren't on the diagrams in the manual. MSD tech hasn't been much help so far. Some show that they go to the "mag", but I have no idea what that is, or if these wires go unconnected.

Steve

[Raynald]

Hello Steve

This is a diagram of my setup ...


do you have good weather Steve in your area ?
here in Quebec it is very bad since the begin of the month...

Ray

[project 911]

Hi Raynald,

Nice to hear from you. Thanks for the info and the illustration. The problem (well one of them) is there is no white wire in the main bundle coming out of the box. There is one on the other end, but I thought that would be the tach output. I always seem to end up with some drama.

Weather... We've had something like twenty days of rain so I feel your pain.

Steve

[mjmoran]

Steve,

Make sure you use a matched MSD coil, not a Bosch blue or any other as the resistance is not set correctly.

Magnacore KV85s work great for the plug wires eliminating the Breu connectors that are...well...junk.

Good luck,

[randywebb]

no tach adapter needed for a '73.5 car - I posted before on this and you can search that thread up to see if anyone with your year posted results; otherwise, it's hit or miss

post your results

[kenikh]

Definitely convert to Crane or Pertronix if you are worried about burning out the rotor. Medium investment up front, but you'll never burn out a rotor or have to adjust points again.

[RoninLB]

Originally posted by kenikh

Definitely convert to Crane or Pertronix if you are worried about burning out the rotor. Medium investment up front, but you'll never burn out a rotor or have to adjust points again.

nice advise but I don't understand how the Crane or Pertronix would prevent speed limit rotors from toasting ?

[kenikh]

They don't have rotors; they are optical/magnetic.

[project 911]

Thanks guys-

I did upgrade to the Crane optical, but it does still use the rotor. It seems to be an issue with some, but not all (burning up rotors).

Does anyone know if I can just get some Accel spiral wires and apply my ends? All this stuff is killing my budget, so I really don't want to spend a fortune on plug wires if possible. The MSD stuff all says "warning" do not use with solid core wires. I never know if that just means it may not work as well, or if means it will damage the MSD parts.

[david c.]

What is bad news about a Bosch blue coil and the MSD unit?

[kenikh]

You can't use it. They are non-compatible. You need to replace with something like the MSD Blaster 2.

[david c.]

Here's why I ask. I just paid a mechanic to install both an MSD and a new coil. Long story, because this is the type of work I undoubtedly would rather do myself. But, since he did it, I didn't do any homework on the parts because I trust him. Anyway, it's got a 6AL and a Blue coil on it and it seems to run fine.

[kenikh]

Interesting; I could have sworn I read recently that the blue coil was not supposed to work or at least fail quickly. I'd search "MSD blue coil" and see what can be found.

[david c.]

I will do that. I wonder what the reasoning is, though.

[kenikh]

As for the technical reasons, I don't know. I only have Pelican hearsay on this one.

[Steve@Rennsport]

Originally posted by dave cardone
Here's why I ask. I just paid a mechanic to install both an MSD and a new coil. Long story, because this is the type of work I undoubtedly would rather do myself. But, since he did it, I didn't do any homework on the parts because I trust him. Anyway, it's got a 6AL and a Blue coil on it and it seems to run fine.

Dave:

Your MSD will start and run OK with Bosch blue coil; you simply lose 4-6 HP.

I've seen this several times on the dyno and its due to the wrong impedance of that Bosch coil with the MSD and ignition's performance is degraded. Further, one can suffer an MSD failure since its drawing too much current with the incorrect coil.

My suggestion would be to either use the MSD High-Vibration blaster coil or HVC one; you (and your engine) will be very happy,....

[mjmoran]

I was waiting for your responce Steve...You went straight to the heart...HP loss!

cheers,

[project 911]

Can anyone comment on the plug wire situation?