MSD back to CDI - Help

[ivanuf]

The car I am working on is a 77 Turbo Carrera and I want to remove the MSD and put back the CDI box. The distributor has (2) cables coming out of it, so I guess it also has a electronic ignition kit installed. How do I go back to the CDI, what parts I need to replace or put back in place and are they specific to turbo cars or all CIS cars of the same time used the same components?

[ivanuf]

No one?

[copbait73]

I'll try. I converted my car to MSD with adjustable boost retard and if I had to go back I would get out the factory wiring schematic. All of these cars are very old and no telling what else has been rerouted on yours over the years.
I'm seeing some sketchy stuff in your picture.

[T77911S]

its tough to help on a forum without lots of pics and details of what is going on with your car especially when it has been modified.
from your pic you have a big mess with a lot of black tape covering everything up.

the wiring diagram is your best friend right now.
if you have the original connector that plugs into the CD that is a big plus.
I did look at the 77 diagram and it shows 2 wires coming off the dist just like on my 86.
BUT, the wire coming off my dist is a coaxial wire. meaning that one conductor is inside the other.
I don't know I if the 77 was like that. I would assume it was.

so It would help to see a pic of the actual wire coming off the dist.
also a pic of the plug for the CD

[unclebilly]

Is there pertronix in that dist? That could explain the extra wires...

[ivanuf]

I will take several more detailed pictures, of the distributor and the plugs.

[m42racer]

Originally Posted by unclebilly

Is there pertronix in that dist? That could explain the extra wires...

Good point. The extra wire could be the +12V source for the hall effect sensor.

I thought all 6AL boxes required a Reluctor signal though. I may be wrong.

Here goes. I just went through this myself when I changed over to a new system.

The original Bosch CDI required 6 wires.

31/1 CDI Ground
TD Tach output
31/d Distributor neg signal from reluctor sensor
A Coil +ve, (coil -ve was grounded in engine harness)
15 CDI +12V switched
7 Distributor positive signal from reluctor sensor

Where these wires are in the car now, you will have to find.

I wouldn't mess with the factory CDI either. These are getting old now and the rebuilds are marginal at best. I paid for an upgraded unit and it crapped out within a month. Permatune all over again.

Look here Replacement Upgrade Ignition – performancedevelopments.com for the best unit currently available. I just did this.

It's a simple replacement with a short adapter harness. No wiring is required. Comes with a better coil, coil mounts wires etc. I have this and many others have changed over with zero regrets. More reliable and better engine performance.

[T77911S]

the MSD will run with points or magnetic PU.

[Jonny H]

If you want a plug and play fully mapable CDI unit, check our CDI+ unit out. It's a proper multispark too, all the way to 10000 RPM.

We can put our electronics in an original case too.

http://www.classicretrofit.com/products

[turbo nut]

IIRC 76-77 turbo's were 8 pin boxes

[ivanuf]

The wiring harness is intact with the 8 pin plug. I need to take the distributor apart and take some pictures. Now I need a 8-pin CDI. Core...

[ivanuf]

Ok, here are some pics of the distributor.

The cable seems to be a homemade version of the green single wire.

I will take it apart and shot inside to see if it original or Petronix add-on,

Also note the bent leg at the distributor, why will they do that to the distributor for the MSD? vs. the original CSI??

[1979-930]

Originally Posted by m42racer

Look here Replacement Upgrade Ignition – performancedevelopments.com for the best unit currently available. I just did this.

It's a simple replacement with a short adapter harness. No wiring is required. Comes with a better coil, coil mounts wires etc. I have this and many others have changed over with zero regrets. More reliable and better engine performance.

Maybe it's a Generation thing. But I have a hard time having confidence in a company and their technical abilities to design an ignition system when their website sucks.
A one page description on how an ignition system works and no other information, what qualifies them to design it?, references on who uses the system, cost, ect... even one picture of the kit would be nice.
I would have a hard time buying this system without more information.

[356911930]

Do 1977 930 turbos have ccw rotating distributors? The 1975-76 rotate cw.

Rahl

[ivanuf]

Any good leads for a 8pin CDI Core?

[Speedy Squirrel]

The arm on the star wheel should not be bent.
If it were an aftermarket trigger, there would be no star wheel.
The yellow reluctor coil that is visible also indicates a stock variable reluctance system.
The home-made wire lead needs to be replaced with the correct shielded wire.
Did you ever get the proper wiring diagram?

PS Counter-clockwise distributors started with the 1978 turbos.

[T77911S]

I must say that dist looks like hell. where has it been, under water?

looks like something got wedged in there and bent it. if you cant get it straight then you need to replace either that part or the dist.

I don't know the 77 so I don't know if the 2 wires are factory. either way, the signal coming out is still the same. you one + wire and one - wire. note: these are not really + and - like the battery, its kind of like AC power in your house.

I also don't know why your car has 2 extra pins on the CD unit or other than the connector is 8 why you could not goto a 6 pin unless you are trying to go back to original for value.

if you don't HAVE to be original the MSD is a good setup. if it ran bad I think you found a major reason why with the bent pole in the dist. the new MSD has a built in rev limiter that is adjustable with a dial on the outside.

you may also be able to find a 6 pin wiring harness and use a 6 pin CD.

check with jonnyH above. I think he may have a pretty good CD. by the time you source an 8 pin and have it repaired you may be better off with his.
just some options to think about.


back to the 2 wires.
all the ones I have seen are a coaxial wire. IE, one wire inside another. this is probably done to suppress noise getting on the wire. looking at your pic it does kind of look factory. most aftermarket terminals don't have that little tab sticking out off the back. that tab keeps the terminal from pulling out like yours did. the black holder also looks like it has holes for those 2 terminals.
without getting into this too deep, when connecting an MSD up the 2 wires are swapped going to the MSD. IE, the + is now the - and the - is now the +. so don't go by how it was connected to the MSD.

[Speedy Squirrel]

Probably don't want to straighten the star wheel. The air gap is important. They are readily available new. A BMW 6 cylinder part is the same.

[356911930]

PS Counter-clockwise distributors started with the 1978 turbos.

Ivanuf, it looks like your distributor has been replaced with a ccw rotating distributor from a later model. Were you aware of this?

If this distributor has not been run on this car you will need to change the drive gear on the crankshaft.

Rahl

[Speedy Squirrel]

It would neither turn nor lock down with the wrong gear. Maybe the whole engine is a '78?