Which starter to use for a 3,0 SC in a 1972?

jsoderbe · 11-09-2010, 03:54 AM

Hi,

I'm just putting in a 3,0 SC in my 1972, mated with my 1972 915. The starter does only have the big plus connector and one more connector for activating the solenoid (I guess).

However, the 3,0 engine wiring harness have the red plus cable and TWO more wires.

So, do I have to switch to a newer starter? If not, which wire to I cut and isolate?Please advice.

Johan

blucille · 11-09-2010, 04:07 AM

I've got the same setup....

I'm pretty sure almost any starter will work, I bought our host's gear reduction starter and really like it.

the heavy red wires go together on the main lug, I believe one goes to the battery, the other to the alternator.

then, there were 2 yellow wires, one was fuel injection related, the other came from the key, again, these can get connected together and to the terminal on the starter....my understanding is that this yellow wire (the important one is connected to the ignition switch) tells the fuel injection system that the car just started, and makes it dtermine if cold start mode is required.....

Flat6pac · 11-09-2010, 04:09 AM

The yellow/blue is the cold start which in the past was part of the selenoid wire.
Bruce

jsoderbe · 11-09-2010, 06:36 AM

OK, thanks, so I just wire them together on the one available connector?

Johan

blucille · 11-09-2010, 06:45 AM

probably.....depends what you did with the wiring harness on the engine.

that being said, in my case they were both yellow, I checked out some wiring diagrams and saw some posts on the forum, and determined in my car, a '72 T with '79 3.0l with CIS the wires needed to be connected together to the starter motor.

boyt911sc · boyt911sc's Garage

Quote:

Originally Posted by jsoderbe

Hi,

I'm just putting in a 3,0 SC in my 1972, mated with my 1972 915. The starter does only have the big plus connector and one more connector for activating the solenoid (I guess).

However, the 3,0 engine wiring harness have the red plus cable and TWO more wires.

So, do I have to switch to a newer starter? If not, which wire to I cut and isolate?Please advice.

Johan

Johan,

The early cars ('72-'77) like yours have the two (2) terminal type starters and the later cars like SC's & Carrera have the three (3) terminal type starters. The main difference betwen these set-ups is the presence of solenoid starter (terminal #16).

Using a three (3) terminal starter would utilize all the wires in the engine harness (3.0 liter SC). Including the small yellow wire from starter (@16) to thermotime valve (TTV) and CSV. But if you decide to use your old starter with only two (2) terminals, you need to get power to TTV & CSV from terminal #1 (14-pin connector). The small yellow wire to the starter (3-terminal starter) is the power line to the TTV & CSV and will be FREE if you use your old starter. So you need to hook up the 2 yellow wires together to the starter.

I'm having problem attaching pictures to this post that could illustrate how this could be done. PM me your email address and will forward some pictures.

Tony

jsoderbe · 11-09-2010, 10:23 PM

Thanks Tony,

it's really not a big deal to change to a newer starter, so I can do that. My only concern is that the 3 terminal starter is in unknown condition.

So, easiest way sound to be to change starter. Then I have less to worry about when installing the 14 pin contact, right?

Johan

aigel · aigel's Garage

Time to get a light weight starter!

G