wiring for a 3.0 with Webers

[ckissick]

I've installed a '78 3.0 to replace the '74 2.7 in my '70 911E. The Webers in the 2.7 are now on the 3.0. I replaced the tach and have the CD box for the 3.0. The 3.0 came without the CIS.

What do I do with all the wires? There are a lot of wires that seem to be for the CIS, but with the carbs, many wires will not be used. Which wires do I use, and can this be answered without being there looking at the car? The alternator in the fan is wired, as is the oil temp (or pressure?) sender next to the pulley, and the starter motor. What's left are wires to the distributor, maybe the coil, the oil temp sensor (pressure?) near the breather hose, and 1 or 2 connectors in the CD area. Thanks for any help.

Charlie
Montara, CA
1970 911E 3.0 (almost)

[ckissick]

bump...

Another issue: The old permatune had a 3-pin connector; the new CD box has a 6-pin connector. Any thoughts? Please, I want to drive the thing.

(BTW, I tried to get it towed to a wrench, but my steep driveway and lowered car thwarted the tow truck. So the car is marooned where it sits.)

Charlie

[Grady Clay]

Charlie,

Good for you, sounds like a great project.

I assume you have installed the engine wiring harness that you used with your 2.7. That is the easiest way to go. The wires should connect just as they did on the 2.7.

Another issue is the alternator. Make sure the alternator and voltage regulator are of the same manufacture and compatible. If in doubt, put your 2.7 alternator in the 3.0.

Is there a separate small wiring harness from the coil and distributor to the 6-pin CDI? Preferably use that. The power to the CDI and the tach connections will need to be addressed. Get the wiring diagrams for both the engine year and car year. Good that you have the later tach, the earlier one won’t work properly without some help.

If the engine hasn’t been run and you aren’t absolutely certain about the gauges, I would install a temporary mechanical oil pressure gauge.

How is the cooling? Do you have a front cooler? What is the fan configuration and ratio? Very important with your nice new SC engine.

Best,
Grady

[jpnovak]

What is your email? I used the engine harness from the 3.0 in my swap. I had to adapt the 14pin connector and tape off a few CIS system plugs. I can send you a spreadsheet diagraming the 14 pin connector changes.

The other things you will need to address is the magnetic trigger for the CD unit. This should be part of the 3.0 engine harness.

I should be firing my project this weekend after 2 year. Yes appropriate precautions will be taken prior to starting.

[Grady Clay]

Jamie,

Here is a good thread;
Need 69 wiring diagram
If you need and this thread doesn’t have them, I think I have originals for ’71.

My e-mail is gradyclay@hotmail.com

Best,
Grady

[jpnovak]

thanks Grady, I used the Haynes manual and the color diagrams on the Pelican home page. I just got my copies of the factory manals. the 71 was fairly easy to adapt, unlike the 69 with the multiple connectors. I think I swapped 3 or 4 wires in the 14pin connector.

The one thing I am not sure about is the Voltage regulator. the 71 has the 3 pin plug in the short section under the panel and the 78 has the 3-pin plug coming from teh engine wiring harness. I looked over the diagrams and they appear to be redundant systems. I chose the 71 plug and will see if that works. the same blue/red/brown/black come through the 14 pin connector from the alt. If not, I will have to switch them.

[Grady Clay]

Jamie,

WOAH Hoss. Voltage regulators and alternators are not something you just “try.” This is an area where careful planning will prevent some “pFtz” instantaneous disaster.

The first thing you need to know is the P/N of the voltage regulator and the alternator. Next, are they an appropriate combination. There are components from Bosch, Marrelli, Motorola, and more. Not all are interchangeable.

Best,
Grady

[ckissick]

Grady,

I did not use my 2.7 wiring harness, because of the newer CDI. The old Permatune had a 3-pin connector, and the new Bosch CDI has a 6-pin connector. That's a main source of uncertainty. Actually, the whole thing is confusing. I have a 1970 911E that had a '74 engine with Webers and an internal-regulator type alternator from 1982. Now, I have a '78 engine with Webers and the '78 alternator. Sort of like Frankenstein's monster.

Since I don't have an external regulator, I'm going to swap the alternators so I will be back to the internal regulator.

Where do the 6 pins in the CDI go to/come from?

Jamie,

my email is sigmaprm@pacbell.net. What about the magnetic trigger? What do I need to know about that?

Lastly, yesterday I tried to turn the engine over with the starter and with no juice to the coil, to get the oil flowing. All I got was a click and the starter would not turn. My battery's fully charged, and I can hand-turn the engine. I called Dave at TRE, and he said my Bosch solenoid is not strong enough to turn the starter motor over, and I need to buy an early Ford Mustang solenoid and bypass the Bosch solenoid to get more juice to the starter motor. I found no mentions of this on this site: has anyone else ever heard of this? Dave is certainly reliable, but I'd just like to hear about any other experiences with this. Thanks.

Charlie

[jpnovak]

Grady, I know I have the correct alternator and VR. they were both the same from 71 and my RoW 78. both are Exteranal regulators and of the same manufacturer. The difference is in the wiring.

ON the 78, the VR clip is part of the engine harness. The wires run from the alt. to the VR and then to the 14pin connecter on the panel.

The 71 goes from the alt through the 14pin and then to the VR and off into the main harness.

the question is do I plug in the VR in front of or behind the 14pin connector? Maybe I have to plug a VR into each. I can make that happen. I have studied these wiring diagrams over and over.


Charlie, The 6 pins on the CD unit go to the 3.0 engine wire harness. If you are not using CIS you can use the 3pin system currently in the car. The extra pins are used to power various CIS components that are not used.

The dist has a magnetic pickup. this takes a special 2pin plug that is part of the 3.0 engine harness. It goes to the CD as a trigger, similar to the wire from the points.

email is on the way.

[rudy sanchez]

I too have applied the 3.0 w/ webers into and earlier 911 (mine is a 71 911t)

actually I had my wrench install it but it came back to me running but needing a lot if finishing work.

I chose to MSD the CDI box issue. works great but I have no tach at the moment. have the adaptor but it's still in pckg. my wrench didn't want to do something new.

car runs great but I have no oil pressure and temp gauges... still not reaching WOT but that might be best for now.

p

[Grady Clay]

Charlie,

With the not cranking issue, I would check and clean the ground straps
and make sure the battery and connections are OK.
Even if you have a 0.8 HP starter (not 1.5 HP) it should turn over just fine.
No, it doesn’t need any Ford parts.
Remember to also disable the fuel pump when cranking the engine.

Yes, using the ’82 alternator-regulator should continue to work properly.
I think it is the more capacity (higher amps) of the ones you have.
I assume you kept the same fan housing with it.
The later ones are machined deeper to accommodate the longer alternator.

You may want to disassemble your two engine wiring harnesses,
leave out the unnecessary wires,
and reassemble with new heat-shrink tubing.
It is not difficult to do.
It takes careful advance planning and careful reassembly to get all
the connections back in the right place in the plugs.
The connections for the ignition distributor should be in, or siamesed
with, your SC harness. Go look.

Power for the CDI and the tach connection will be an issue.
Go look at where they are for the Permatune.
Power should be a red wire going to the center terminal on the Permatune.
There should be a single plug connection for that red wire very close by.
Originally the tach lead was at the distributor (black with purple stripe) and
went through the 14-pin engine connector to the RPM transducer (speed relay)
and then through the 14-pin chassis connector to the tach.

Please send me a link to the exact engine wiring diagram for your new SC engine.
Try and confirm all the connections and wire colors.
This way we are on the same page – so to speak.
I have wiring diagrams for both ’70 and ’71 (yes they are slightly different.)
What e-mail address do you want me to send them to (sigmaprm@pacbell.net) OK?
– there will be several 1M+ files.

OK, back to the engine wiring.

The SC engine has an oil temp sender, oil pressure sender, and an oil pressure switch.
Is your instrument situated for the oil pressure switch (idiot light)?
The wire (green) is in the car but your original “S” instruments didn’t have
the light – just the gauge.

The engine 14-pin connecter originally was
(I may have the numbering reversed)
(and the wire colors are on the engine side):

1) Starter – yellow
2) Oil pressure switch – green
3) Oil temp sender – black
4) Oil pressure sender – green/red stripe
5) Power to back-up light switch – green/yellow stripe
6) To back-up lights from switch – gray
7) MFI temperature-time switch – red/black stripe
8) MFI throttle microswitch – gray/red stripe
9) Tach connection to ignition points – black/purple stripe
10) Ignition coil to “intermediate unit” (signal conditioning
for tach) – blue with yellow stripe
11) D+/61 from alternator to voltage regulator – blue
12) Ground from D- at alternator – brown
13) DF from alternator to voltage regulator – black
14) Battery via alternator to fuse #3 – red

Remember, you need the ground strap from the alternator to the case.

Clearly you don’t need #7 and #8; no MFI.
You don’t need #13; integral voltage regulator.
You do need #11 for the alternator light at the dash.
Most other is pretty obvious.
I still don’t know about the tach.
What is the pin-out of the 6-pin connector at the SC CDI?

What electronics do you have on the engine panel?
"

"
(C) 1971 Dr. Ing. h.c. F. Porsche A. G.

Best,
Grady

[ckissick]

Grady,

Thanks for all the help. I have no wiring diagram for a '78 engine. With the info from you and Jamie, and some experimentation, I'll see what I can do. I have no computer at home, so I'll be signing off until Monday.

Charlie

[ckissick]

OK, I'm back. I installed the alternator with the internal regulator. Also, I revealed both wiring harnesses over the weekend, and here's what I found: I'll describe each pin on the 14-pin connector:

#1: yellow wire to starter, OK.
#2: Was blank on the '74 and '78. On the 74 engine, there was no wire to the oil pressure switch. Why? Is it just for an idiot light? I have a front oil cooler. On the 78, the oil pressure switch went to pin #12.
#3 to #7: OK
#8: On 74, it was unused (MFI). But on the 78, it was a purple wire that went to plug "TD" on the Bosch CD unit. ?
#9: In 74, black/purple, to distributer. In 78, red wire to plug "15" on CD unit. ?
#10: blue/yellow to CD in 74. Blank in 78.
#11: blue, to alternator. OK
#12: brown, to alternator in 74. In 78, green/red, to oil pressure switch. Should I move this to #2? Also, should a brown wire go direct to the alternator, or not, due to the new CD?
#13: not used in 74 due to internal regulator, Keep blank. OK
#14: red, to alternator. OK

Remember, the console side of the wiring is as it was for the 74 engine, so I have to match this. However, the new CD changes things.

The wiring on the new Bosch CD, as it came with the 78 engine, is as follows:
31/1: black, to dizzy;
A: clear sheth, to dizzy;
TD: purple, to #8 on 14-pin connector;
15: red, to #9 in 14-pin connector;
31d: brown, to alternator;
7: white, not used.

The wiring on the 74 Permatune CD: (left to right)
black, to dizzy;
red, to nearby connector that goes behind console;
blue/yellow, to #10 on 14-pin connector.

Also, with the internal regulator, does the brown wire go to the unmarked post that is connected to the blue wire post through a little black box and green wire? What is the little black box?

OK, have at it. What should be the final wiring configuration for me? I trust you have enough info now. Thanks.

Charlie

[jpnovak]

having just gotten my engine started here are the final connections on the SC engine harness side. No changes necessary on the 70 console side.

pin #
1 yellow
2 Gn/white optional oil press switch
3 Bk/Grn oil temp
4 Grn/red oil press
5 Yell/green own wire harness- reverse lights
6 Grey/Red own wire harness - reverse lights
7 Open
8 open
9 blk/pur dist. Trigger
10 blank
11 Blue
12 not connected external VR clip
13 not connected external VR clip
14 red

to power the CD unit, Use the 12V switched system under the console and make a jumper to the 2 pin connector (red and brown) on the CD lead for the harness. This is for the 6pin. You can also use the 3 pin by connecting the ground, trigger wire, and blk/purple. The other connectors are power leads for CIS sensors. These can be cut out.

The other issue I had was the starter. There is a cold start circuit that is tied into the starter solenoid. This can be disconnected. use the 12V yellow wire connected to the top, tranny side spade connector. Teh lower outside connector can be removed (blue/yell wire).

I then removed all the CIS connectors. There is a blk/yel wire in a 2 pin clip. do not cut this. It shares a ground to the CD. You can remove it if you jumper that ground connection. I just taped it off.
Good luck!

[Elombard]

Hey

How could I tell if I have an SC tach already? This tach worked with my 78 SC engine in my 73 but not with the 79 engine. I just dont want to buy a new one and have it be a different problem.

[jpnovak]

The early tack will have a silver button that the needle comes from. The later ones have a black.

[ckissick]

Thanks, Jamie.

What do you think, Grady?

Charlie

[ckissick]

I'm back. I've tried to get the car started, but there's no spark. I suspect it's the connections from the CD. I could only find a wiring diagram for an '82, and here's what it says:

15: red, to fuse and battery.
31/1: brown ground, and brown/red to B on coil.
A: white, to B on coil.
7 and 31d: both to distributer (no wire colors given).
TD: black/purple, to tach.

Here's what how I wired it (Based on positions of wires on wiring harness, as I received it):

15: red, to fuse and battery.
31/1: black, to distributer.
A: clear, to distributer.
7: white, to nowhere.
31d: brown, to alternator, and brown/red, to #12 on 14-pin connector.
TD: purple, to tach (#8 on 14-pin connector)

Will the '82 set-up work for me, or is it still different for the '78 engine? I know the distributer changed after '79, so there may be a difference. Perhaps the car that my '78 engine came out of had a non-Bosch CD system (like MSD), explaining the discrepency in wiring.? So, how can I get this thing to fire up? Again, thanks.

Charlie

[jpnovak]

Do you not still have the 6pin plug that goes to the dist still attached to the SC wiring harnes? Follow the exact wiring you have listed in the beg. of your post. the 82 diagram will work.

I see several problems. The 7 and 31d connectors go to the magnetic trigger on the dist. Look for a clip that comes out near the dist and follow those colors to the connections on the CD. You presently have them wrong.


The white wire will go to the pos side of the coil. You have it currently going to the dist. 31/1 will ground the CD unit and the coil.

I am pretty sure that the blk/purple wire goes to #9 on the 14pin connector, not #8 as you have listed.

[ckissick]

Hey, you're fast, Jamie.

You're right, the tach wire does go to #9 (It used to go to #8).

I take it the magnetic trigger you mention consists of a large connector, on a single green wire, that connects to the two wires. The connector has a wire hoop to hold it together.

Charlie