It is time to consider the wiring changes necessary to light up a 3.0 6 verses my downtrodden lowly 2.2L 4.

The 911 wiring harness that came with the motor (core) has a host of useless attachments for the FI from the original 911 application.

To further complicate matters, the character that removed the (core) engine from the donor 911 used a big pair of dykes to snip the wires leaving the alternator / in one fell swoop!

Anyway,.... I have what is left of the harness to establish wire gauge but my questions revolve around the best way to rewire my new build to the existing wiring in my 71 and how much of the old wiring can i reuse in the conversion......

Any assistance would be greatly appreciated.

The best ways involve sitting down with the wiring diagrams for both the 914 and the 911, and looking at what the wires to the engine do in each case.

Since you mention "useless FI" on the 911 engine, I assume you are going with carbs? That simplifies some things, but does make for more complications as the 914-4 wasn't delivered with carbs and there isn't much provision for them. (Yes, oh Peanut Gallery, I know--but this car isn't a Euro-spec 1.8 nor an original Six.)

BTW, there wasn't a lot of electrical stuff in the CIS system on the 3.0 SC engine. Depending on the year, there was basically the warm-up regulator and the fuel pump. Later ones had the O2 sensor circuit as well.

One big change is that the 914 alternator is externally-regulated, while the 911 one is almost certainly regulated inside the alternator. So there may be fewer wires coming out of it to deal with.

Remember that the wiring colors are pretty consistent; brown is just about always ground for instance, red is almost always +12V, and so forth.

--DD

Dave that's assuming people can read the factory wiring diagrams,not a lot can ,anyone colour blind is screwed for starters,the manuals are enough to make your eyes bleed besides.
Wiring can be changed on the 12 pin relay board plug and the 4 cyl relay board retained,I didn't have the time to sort this and got a custom loom built,not worth using the 911 loom cause its old and needs to be changed too much to be worthwhile.
Useless FI is a redneck comment the system on these motors was not for performance but in good condition works very well and very useable.
I would take injection any day but can't afford a 911E motor or for that matter a 3.0SC.

Is this 3.0 carbureted or injected? The CIS doesn't require much in the way of circuitry.

To answer the question you asked in the title of your thread - easiest is to have a custom wire harness made so it's plug and play.

See if this works for you...

Thanks Dave:

Yes / Webers on PMO intakes/ on an 82 3.0 so the regulator is in the alternator area i presume. I am wondering if I can also ditch the relay board in the engine bay for to clean up the clutter and to better provide for the oil tank fittings???

Luke: That helps much. Thanks for all of the input.

Yes, as long as you are providing power for the fuel pump from another source.

Most of the conversion wiring harnesses that I make are optioned to delete the engine bay relay board. Custom conversion wiring harnesses are one of the services I provide. http://www.914world.com/bbs2/index.php?showtopic=24228

Luke is one of a handful of guys that got a kit.

I used the PMS conversion harness for my 3.6L, it eliminates the /4 relay board and plugs directly into the /4 main harness.

I only had to switch two wires that were swapped. Oil temp and oil pressure if i recall correctly.

Other than that it was plug-n-play. Literally.

3.6L
http://www.patrickmotorsports.com/part/914...993-36l-engine/

3.2L
http://www.patrickmotorsports.com/part/914...911-32l-engine/

Call them, they probably can make you one for your /6 engine ...

"What is the simplest way to wire up a 6 in the place of a 4?"

I contacted Perry Kiehl on this forum after Jeff Bowlsby recommended him for 914-6 conversion harnesses. Great to deal with, nice sanitary work for a very reasonable price. Here's a pic:


Click to view attachment



-Harry

The bit about reading the diagrams is a good point. But if you are unable to read wiring diagrams or tell what color the wires are, then you're not going to be doing wiring yourself anyway.




That wasn't an editorial comment on my part--I just assumed that the original label "useless" meant "not going to be used in this case".

Anyway, the purchased harness is indeed the easiest way to go.

--DD