Thoughts on a 3.0 SC engine in a 1970 911E

[PeteKz]

I'll reinforce what Thomas and Gordon said, plus some additional suggestions. I did a similar swap, a 1980 RoW CIS engine into a 1973.5T (CIS) car.

Yes, you need the 6 pin CDI box as discussed. I recommend that you keep the wiring from the distributor to the CDI box separate from the engine wiring harness. On the 1980 engine they are taped together and the black/purple wire goes through the 14-pin connector. If you keep them separate, then if you decide to go with a 123 distributor or some other ignition changes, you don't have to unwrap and pull apart the engine harness.

On my 1973.5 car, the original tachometer works with the black/purple tach signal from the SC CDI box connector. I don't know if the 1970 tach is different, but John Bell, "jbell959" on this forum, specializes in gauges and would know and have whatever you might need to adapt them.

Alternator: Did you use, or do you plan to install, an alternator with an internal voltage regulator? That will simplify your engine wiring harness by eliminating 1-2 wires and the VR on the panel.

[BobNorman]

Wow. Thanks everyone, some really good information here, thanks for taking the time to help. This forum is such a great venue for good people to help others.

Yes, I have the Euro distributor with the magnetic pick up instead of points, so 6 pin it is. Also good to know about the tach adaptor can! I’m unsure if I have it, but there was a silver can on one of the 70-71 fuse panels that I have. I’ll get a pic of the unit, hopefully with a part number on it, and post it here, fingers crossed I guess.

Given that I have all the components I’ll stick with the CDI for now, but I will consider the 123 ignition as well, particularly if the CDI unit doesn’t work – I bought it used a few years back and have no way of testing it... To that end, and to the point above, I think I will do a separate harness for the CDI. I have seen this somewhere along the way and may try to purchase or assemble something similar.



I don’t have the plug for the unit, but if all else fails I could just plug them in individually. I’ll also have to figure out how to split the green coaxial cable as well.

I do have the original Marchal Alternator with separate VR. I initially bought a Bosch VR, but have since located a Marchal VR, as I understand they have to match. As for the alternator portion of the harness, that all lines up so I don’t anticipate a problem there.

Thanks again, I'll be posting more I'm sure.

[Schulisco]

You mean the white 6pin connector/plug?

Google for AMP tyco T6,3 or Faston 6pin connectors. The plug to the dizzy and the green cable is also available separately. Not cheap unfortunately...

More information:
https://forums.pelicanparts.com/porsche-911-technical-forum/1151696-ignition-question-71t-s.html
https://forums.pelicanparts.com/porsche-911-technical-forum/1135566-msd-street-fire.html
https://forums.pelicanparts.com/porsche-911-technical-forum/1125089-ignition-options-123-vs-perma-vs-cop.html
https://forums.pelicanparts.com/porsche-911-technical-forum/1124898-cdi-replacement-battery-disconnect.html
https://forums.pelicanparts.com/porsche-911-technical-forum/1027517-123ignition-distributor.html
https://forums.pelicanparts.com/porsche-911-technical-forum/1112772-83-sc-no-start.html

Thomas

[BobNorman]

Thanks for the info on the connector and the other links. I'll check them out.

This is the silver can i have on my panel. Two wires going to it are Red and brown. Doesn't look quite the same as the unit posted earlier but hoping it was a replacement maybe?

[PeteKz]

That's an ignition noise suppressor. You can safely delete it. Modern audio systems do a good job of filtering out ignition noise, so you don't need those anymore. If you're old enough, you will recall hearing a noise on olde analog radios when the station signal was weak that rose and fell in time with RPM. That was ignition noise being transmitted through the air and through the wiring harness.

Throw it in your box of parts that "maybe I'll need someday if I do a concours restoration."

[BobNorman]

Yes, thanks, I just figured that out. I am old enough that I do remember that, you can hear something similar in the beginning of Wish You Were Here. I have a Blaupunkt Frankfurt for the car so I’ll probably end up using it. I also went down a 1970 tach adapter rabbit hole. I did find that I need a Bosch unit part number 0 227 990 001. Just found and purchased one, obviously used but hopefully in working condition. Those tach adapters seem to be like hen’s teeth and rocking horse poo.

Also, I discovered they are referred to in a number of ways. They are called “Switching SCR” in the 1969 diagram, “Intermediate Unit”, for the 70, and also referred to in the manual as “RPM Sensor”. Nice, no chance of confusion there!

[Schulisco]

Bob, read this posting (and the whole thread for more info) according protecting the tachometer when mounting an 123 or different dizzy with breaker points instead of inductive signals:

https://forums.pelicanparts.com/porsche-911-technical-forum/1151220-perma-done-2.html#post12161113

No values available, but I suppose the zener diode is a 12V 5W with a resistor of at least 1k or so?!? Or better a suppressor diode like the 1N5908
Never tested it by myself, but the proof is in the pudding...

Thomas

[BobNorman]

Thanks for that. So much good information on here. And helpful folks to point people towards it.
Cheers.

[BobNorman]

So I’m now about ready to start to build my stand-alone 6 pin harness for the CDI. Thought I’d post this in case it might help anyone and to ask a question.

I now have the 69-71 only Bosch 0 227 990 001 Tach Adapter/RPM Sensor/Intermediate Unit/Ballast Unit, as well as the six pin plug connector, which can be found by searching AMP 180904. I got the connector from Digikey Canada for $1.05 +$8 shipping.

The other connecter for the green distributor wire is on the way. It’s the same connector as was used in many fuel injection systems- an EV1 fuel injection connector. I bought a Bosch one, part number 1287013003 for $17 shipped, but there are much cheaper ones available. Have not received it yet, but I’m told it’s the one I need. All that said I can now start to build my CDI harness- I could have bought one for $289USD plus shipping and duty to Canada, but what’s the fun in that...

Im a visual guy, so after searching through a few posts here, I drew up my own diagram.


Pretty clear so far, but I do have a question - How do I wire in the tach adapter? I found this diagram-


So, I have to run a wire (A)to ground and (B) straight? to the to the positive (15) side of the coil, but (C) the black and purple wire to tach- how does that run with the black and purple wire from the 6 pin CDI unit? Is it just in series from the CDI, to the tach adaptor, and then onwards to the tach? Does the order matter?

Thanks again for the help and support.

[BobNorman]

I've encountered a hiccup in trying to get the engine mated to the transmission. I've got the proper clutch and disc installed, and have everything ready to go, but the oil crossover pipe is in the way because of the clutch cable mount tab.




I'm not sure what people do here, reroute the pipe? Bend it? Or remove it and reinstall it after the engine and transmission are put together. Question is then will it foul on the clutch cable?

Any advice? Particularly from anyone who has put a 3.0 onto a 911 transmission?

[john walker's workshop]

Bend as needed or use the over the top flex hose that was stock.

[PeteKz]

I have an SC engine in my 1973.5T, with 915 trans. It fits fine. I think the lower pipe got bent up, possibly by someone jacking up the car via the engine, and they didn't use blocks to avoid putting pressure on the pipe. Carefully bend it to where it should be.

[BobNorman]

Originally Posted by john walker's workshop

Bend as needed or use the over the top flex hose that was stock.

Thanks John for your response. Can you provide a little more information on the over the top flex hose? Do you mean that was stock to the 3.0 or to the 2.2 the car would have had? And if original to the 2.2 would that work with the 3.0 fittings (oil tank etc)? The 3.0 had this pipe installed when I bought it, so I assumed it was stock. As for the 2.2 the car came to me without an engine, so I don’t know what would have been there. If you could provide a part number I’d be grateful.

[BobNorman]

Originally Posted by PeteKz

I have an SC engine in my 1973.5T, with 915 trans. It fits fine. I think the lower pipe got bent up, possibly by someone jacking up the car via the engine, and they didn't use blocks to avoid putting pressure on the pipe. Carefully bend it to where it should be.

Thanks Pete, I’ll have another look. This is the 911/01 transmission with the pull type clutch, I’m not sure if the 1973 915 has the same tab for the cable that the 911 has. A pic from the net for clarity.


Also the engine has SSIs fitted, so it’s a pretty tight area, but I definitely take another look.

[PeteKz]

I have a 915 /40 with pull cable clutch. Pretty sure it is the same. I will have to scoot under it tomorrow and take a couple pics.

[Ian Comerford]

On later 915s, well the one fitted to my 79 SC, the clutch bracket is a bolt on item. If everything else fails you could consider cutting that one off and making a bolt on one or buying the Porsche item so that you can fit the box and then fit the bracket. Just a thought

[doswald]

Bob, the 2.2 engines had the over the top flex hose.

The 70-71 cars had a unique push type clutch setup. It’s hard to describe, but there are numerous threads on the topic.

dho

[PeteKz]

On my 915, the clutch cable goes through a hole in the transaxle below the CV joint, so a different setup than yours.

[BobNorman]

Thanks again for the help.

So I’m looking at the 2.2L flex pipe (901.107.331.12), I think that is the one anyway. I am wondering if it will fit on the 3.0L? From what I’ve read, I think it is smaller in diameter, and the fittings are smaller as well, so I’m not sure that is a solution. I understand that there are fitting adapters available, which I would have to use on both ends (I’m using the SC oil tank), but even still I would end up with a more restricted flow than what was stock for the 3.0.

Would anyone know if there is a later (larger) flex pipe that will fit the SC engine available?

I know that this conversion has been done many times, just wondering what folks use?

[BobNorman]

Found this crossover pipe which is said to be a universal fit:

https://www.pelicanparts.com/More_Info/ERMP0180000.htm?pn=ERMP-0180000&bc=c&SVSVSI=4232

But… Pelican says it won’t work with 901/911 transaxles!

However… Elephant Racing says “Fits all 65-89 heat exchangers/SSI/headers. Fits with 901/911/915 transaxles, does not fit G50 transaxle. Fits all clutches including early “pusher” styles.”

Same part number so which is it?

Regardless, I’d still like to use a flex pipe option, as was used on the 2.2 but am not still sure about the threaded fittings- if they’ll work with the 3.0. OR, if there is a different flex pipe option for the 3.0.

I know others have done this... Anyone have any insight?