MSD ignition installation

[Stingray72]

Hey all,
I'm about to install a complete MSD setup including distributor, 6AL box, and plug wires. A lot of the wiring in the car is in pretty bad shape including the old, white cloth-wrapped resistance wire which currently goes to the + side of the coil and will be called upon to turn the new ignition on and off. I would like to replace this wire. Does anyone here know where it terminates and how to get to it? Does it terminate at the ignition switch or the main wiring harness? Is it easy to get to, or should I just leave it an bypass it with a new wire until I can really tear into the wiring system? Has anyone had any experience with this?

Thanks a lot!

 

[69MyWay]

Don't know if I am answering your exact question, but if your wires are in bad shape, go under the steering column to the ignition switch. You will find the coil wire picks up right there after the fuse panel, and routes back out to the engine. If I were you, I would start right there with a fresh good quality wire and feed it out to the engine to to the install.

This will give you a fresh clean non resistor wire to do your thing. Several people here at CAC have MSD systems and have found it best to mount it in the passenger inner fender well facing the firewall.

Make sure you have a good clean ground connection from the engine block to the frame out near the fuel pump, and run all your grounds to the block or to the frame to make sure that MSD sparks right.

Good luck.

 

[Rowdy1]

Do It

I'm not sure about your 72, but I'm in the process of installing a Painless wiring harness on my 62 and that wire you refer to is off the key switch on mine. I also as 69MyWay said, mounted my 6AL box in the passenger fenderwell inside the car. As a result of having a wiring toilet under my dash from prior repairs made before I bought the car, I opted to do the COMPLETE harness, every wire, connector, pigtail, bulb and a total of three ground blocks. It's a bit of a time consuming job, but well worth it. If you have any doubt about a wire, trace & replace or it will come back to bite you later.

 

[Hijinx]

I replaced this line in my '73 when I went to the Ignitor II in my distributer. I cant remember the exact location on the firewall connector it runs to, but here is what you can do. The firewall connector for the whole compartment is on the firewall beside the steering column shaft. It is held in place with one center bolt. Take that out and pull the entire connector out and up a bit. With a tester just do a contnunity test to find the exact wire. Once you find it the connector is a splay lug kinda deal. If you take some needle nose pliers you can squeeze the base of the connector together (from the inside of the housing) and pull it out whole. You can get these little connectors at NAPA and just run a whole new wire with the proper connector on the end and not have to do any splicing. I hope this makes sense.

 

[Jack]

Welcome Stingray72

Hi Stingray72:
And welcome to CACC ... this is a great site ROB & the other administrators have put together ... one with lotsa nice folk who like to both help & learn. I've got a 71 that I'm assembling motor for now ... also installing MSD box & coil with gutted HEI dist & 75 vette tach. Chris', Lou's & Rod's info is right on.

I'm in Florence SC (eastern SC where I-95 & I-20 intersect). Gosh, it'd great for me to know a nearby vetter (specially 2 chrome bumpers). Where are you at? You can email me at QAFERRET@aol.com

JACK:gap

 

[cjpck44]

Hey Stingray,

This is my third day on the site and gotten a lot of help already. Love the site! Anyway, I'm with the advice of making sure that you've got really good grounds for your MSD. I did the same thing on my 77 and not having good grounds caused me some pain and a whole lot of time.
Anyway, I wanted to ask a question on this thread also. I put in the MSD-6A with the new distributer and coil, but have to put in the proper adapter to hook my tachometer wire up to so that I can get it working again. I'm having a lot of problems talking to people to find the right part number for this adapter, so does anyone know it offhand?

thanks, chris

 

[Jack]

Hey cjpck44:
Yep ... it's a great site ... Welcome! I asked msd tech about hooking up msd box to factory GM 75-77 electronic tach. MSD told me that the tach output wire from their box should drive the tach with no tach adapter necessary. I haven't tried it yet ... have you tried it that way?
JACK:gap

 

[Stingray72]

Thanks for all the help, everyone. I've been browsing the threads for a few days now and I'm impressed with the forums.

I see that there are a couple different locations of where the wire might begin, but I'm hoping it's where 69MyWay describes it. I have plans to tear out all the wiring and go with a new harness as well, but I only have a weekend to do this ignition install.

Thanks again. If I get it done this weekend, I'll post about how it went.

 

[cjpck44]

Stingray72,

Something as easy as that, of course I haven't tried it. I had some help installing the MSD, my first time trying it and the guy with me just said I would need the adapter so I went with it. I won't be able to check it out now (bit of a broken leg thing) but as soon as I can I will. Thanks for the info I appreciate it!

Chris C.

 

[redmist]

Alternate mounting location is passenger side windsheild wiper well on the firewall side. Easy to hide the wires, away from engine heat and the elements. BTW I used the HEI Petronix internal coil, it's plenty hot enough and keeps the engine bay cleaner. I also have a MSD signal stabilizer installed in the same location on the driver's side.

 

[Wamp]

reply

I'd be real intrested in what you all figure out. I just ordered a tach from a 1976 and want to switch it over to the electronic ignition, If I don't get a crate engine soon for my 1974.

Wamp '74

 

[redmist]

The blade connector on the side of the MSD 6A hooks directly to the tach wire. No problems.

 

[Wamp]

distributer

So whats the best elctronic distributer? Woould like to have one that is all in one, no control module. and one thats easy to hook a tach up to. right now I have stock distributer and went to an Accel Coil, don't like the coil much, it's so big! Hooking a tach up to the coil is easy though. I'll let you experts advise me (where are you Tom?)

wamp '74

 

[redmist]

All electronic distributors need a trigger. This can be externally via a crank trigger or internally via a magnetic pickup
I use a petronixs HEI (because it is a great value) which has been converted for use with a MSD 6a, magnetic signal stabilizer and J&S Safeguard unit.
IMO I still think MSD makes the best distributor from both an engineering and aesthetic viewpoint.

 

[69vettester]

Here are links to details of my MSD probillet install, and 6a module install. Of course the components are matched, so the wireup was straight forward and IMHO the MSD system is tops.

http://www.weavermill.com/dist/installdist.htm
http://www.weavermill.com/dist/ignit.htm

Hope this helps..
Tom

 

[Wamp]

Tom

You put a distributor on that still has the tach drive gears? Can you look up part #'s in Jegs or such and send them to me. I just ordered an exspensive 1976 electronic tach so I could get rid of that gear driven tach distributor. I rubuilt it once and it ate the gears again, big bummer. Hard to tell what the dimensions of the box are from the picture, wonder where I would stick that on the 74. Thought MSD made a distributor that did not need the module.

wamp

 

[Jack]

Wamp:
Dunno for sure what Tom's pn is ... but MSD probillet cable tach drive distributor for Corvete is MSD pn 8572 ... about $275-$300 depending where you buy ... and it requires an MSD box. MSD does make a distributor that does not require a box ... MSD pn 8365 ... but it's essentially same as 75 up vette HEI distributor but has some performance mods ... and it does NOT have a cable tach drive.
JACK:gap

 

[Stingray72]

I got it done, and it was a huge success. It took a little longer than I expected, mainly because of the work involved in replacing that resistance wire.

Here's a summary of how it went for anyone who might be interested:

I had trouble finding a new terminal to insert into the main wiring harness. NAPA couldn't find one in their catalog, and I was afraid I would have to try the dealership. But, lo and behold, as I was looking in Auto Zone just for the heck of it, I found a small package of assorted GM terminals which included exactly the one I was looking for.
After that, the 6AL installation was pretty simple. I made a plexi-glass mounting plate and mounted it on the little flat spot on the rear of the passenger's side wheel-well, as suggested. All the wires from the 6AL were plenty long enough except for the one going to the ignition switch (no problem since I was replacing that one anyway).
The Super Conductor plug wires were all much shorter than the old ones, so I couldn't route them under the manifolds in the same way. Still, there's plenty of clearance around them to keep them from melting.
I've pulled the distributor before so that was no big deal either.

The car runs great now. I had a slight miss previously which is completely gone. According to my voltmeter, the resistance wire was resisting a little too much. It only read 4 volts at the coil when the ignition key was turned on. Glad I replaced it.

The only issue is the tachometer. The distributor was apparently shipped with the distributor drive gear reversed. I think rather than buying the adapter, I'll just flip the drive gear around on the distributor, turn the distributor 180 degrees so the drive gear is facing the same direction as before, and move each plug wire down 4 sockets on the cap. But I'm worried. Does anybody know if spinning the tach cable in the wrong direction will damage the tachometer?

Thanks again

 

[69vettester]

Wamp,
Jacks post has the correct part numbers and info regarding My msd install/wtachdrive. I got it and the 6a module from Jegs for around $450 for both.
This MSD combo really brought the efficiency and power of the motor up to optimal, plus the combo seemed to steady the motor so I could get it timed to 36degrees all in at 3k RPM's. I set the timing one time,and havent had any reason to touch it again, and that was 15 thousand miles ago.
Good luck..
Tom
PS..
Congratulations stingray72