Help with Crane optical trigger connection.

Rod Rios · 05-03-2002, 08:59 AM

Hi everyone, I've followed this board for a long time but not registered until now.
Could someone please help me with the installation of the Crane optical trigger system on my 73 911E targa. I ordered the kit from pelican, of course, as suggested for those with points and original (Bosch) c/d box. The installation into the distributor is pretty clear-cut, the electrical connections however are not. The original wires to the distributor are two, a purple with black stripe wire and a black wire (this one has the switched power when tested with my voltmeter). The optical trigger has three wires, a black one that apparently goes to ground, and a red and a white wire. Can someone tell me which wire goes where and how to connect this thing? Thanks a lot!
Rod Rios
Fargo

Rod Rios · 05-04-2002, 03:20 PM

Oh, oh, I'm in trouble. No replies at all!. Anyone?
Rod Rios

Early_S_Man · 05-04-2002, 09:41 PM

Rod.

Welcome to the home of the Pelicanheads!!!

First of all ... the two wires at the distributor are the same trigger connection for the CDI-unit, Speed Relay (Rpm Tansducer, a.k.a. Speed Switch) for the fuel injection cut-off solenoid, and Tachometer ... and both will need to connect to the output from the optical trigger unit!

I find it very hard to believe that there isn't a hook-up diagram with the Crane unit that tells which wire is ground, battery, and output! Your first call should be to Pelican, and second should be to Crane ... if needed!

I looked at the www.cranecams.com web site, and no installation documents are available! I would suggest NOT connecting any power to the unit until you have a definitve answer as to the color code of the leads! My intuition gives me a good idea, but a 'close' guess could still burn out the unit if it was wrong!

Rod Rios · 05-05-2002, 05:53 AM

Thank you very much for your help, Warren. There are plenty of installation instructions that come with the Crane optical trigger and installation kit, but all are to other C/D units, the Crane fireballs, of course, the MSD unit, etc. No specific instructions for my application. I'll call the Crane people tomorrow. Thanks again. Rod Rios.

Kevin G. · 05-05-2002, 06:45 AM

Hi, Rod

I installed a Crane Fireball XR700 optical trigger in my '72 a while back, and went out to check how it was wired. (I also installed an MSD unit last week, but still remember how the wires were).

I have a three wire cable coming from the dizzy to the optical trigger control unit, and three more connecting the control unit to the car's electronics. The latter three are:

Red - to 12v switched (lowest of the three fuses under CD cover)
Black - to ground (I ran this to one of the control unit mounting screws)
Yellow (your white) - CD Trigger wire. This is a three-way connection with the black (CD) and black-with-purple-stripe (Tach) wires originally connected to your departed points.

Hope this helps!
Good luck and smooth running!

Rod Rios · 05-05-2002, 11:35 AM

Holy Schmoly, it worked! Thanks a lot Kevin.
Rod Rios

Kevin G. · 05-05-2002, 06:22 PM

That's great, Rod

It's nice to be able to help someone for a change. I'm one of those who asks a lot of questions from the experts who hang out here, so those few opportunities where I can help someone else are few and far between.

Have a great time driving!

Al G · 04-14-2003, 04:48 AM

Kevin,

Just wondered if you could also advise how to connect the crane optical with the MSD 6AL. I am sure that I can follow the instructions, but a few words from someone who has gone before would be a welcome confirmation of my understanding.

Al G

911pcars · 04-14-2003, 09:11 AM

Al,
Crane's instructions to connect their optical trigger to an MSD unit are in document #90002006 which is downloadable from their site. If you can't find, PM me and I'll email you the pdf file (I may not have the latest version though).

Sherwood Lee
http://members.rennlist.org/911pcars

ianz · 08-08-2003, 08:52 AM

Hey everyone

I'm having trouble with my 72T. It had the Crane (then Allison) optical trigger with the xr700 system installed by the previous owner back in 85.

The car is now suffering from an intermittant miss, sometime just a stumble during acceleration, others it will hardly run, sometimes it runs fine...

VERY frustrating!!! so my question is, if there is an XR700 box installed, is the stock ignition even hooked up?? or is it bypassed??

I don't want to just wildly throw money at the car replacing good parts.....

Please Help....

911pcars · 08-08-2003, 10:08 PM

" if there is an XR700 box installed, is the stock ignition even hooked up?"

If there is an XR700 box installed, it should be gold or black in color and have a label that says ..... "XR700".

Another indication is a lack of ignition points in the distributor and instead, a slotted wheel and an LED emitter.

Not knowing how the PO connected the wires (twist and tape, solder and/or mechanical joint), it could be an intermittent open circuit somewhere, a bad ground connection or perhaps something unrelated to the box. Switching back to the stock system means disconnecting the XR700 from the ignition system, then replace the points and condenser and reconnect the sytem wires... correctly.

Intermittent malfunctions are more difficult to pinpoint.

Sorry can't help more,
Sherwood Lee
http://members.rennlist.org/911pcars

ianz · 08-11-2003, 08:36 AM

Thanks for all the info everyone.....

The car had the allison XR700 box and optical sensor were installed in 1985, i..e ITS OLD!!!! and does not look like the current XR700 box at all.......I still don't know how the system is wired and whats there and what isn't

I just need to chase ALL the wires and understand the system better

I have talked to everyone from the guys at Pelican, to Crane, to you and its obvious that until I understand the system, the car will sit because no one I've talked to could provide me the info I need...

excuse the rant, I'm just frustrated...It's appearent that I'm not asking the right ?s or providing enough info...

ianz · 08-26-2003, 04:36 PM

FIRE IN THE HOLE!!!!! YA HOOOOOOOOOOOOOOOOO!!!

well for future reference, my car (72 911T) had had an XR700 box and optical trigger installed back in 1985 connected to the stock CDI box and tach inputs....well the XR700 was the culprit but a bit of info for future searchers.....

The crane part # SW715-0020 that pelican sells is a stand alone replacement for points that connects directly to the stock CDI box and tach signals per Kevin G's instructions above (Thanks Kevin).

The main lines to the XR700 unit that was previously installed were connected the same way but then had a separate set of leads that connected to the optical trigger that looks the same as the SW715 optical trigger except the wires are different colors and there is a 3 prong plug on the trigger for the XR700....

So, XR700 box with optical trigger is the same as SW715-0020 optical trigger by itself.

I was told by a tech at Crane that the XR700 box is an amplifier that isolates it’s optical trigger from voltage spikes from the CDI box that the SW715 may be vulnerable to... and it also has a built in adjustable rev limiter, but I digress... he was concerned that the SW715 was not robust enough to work with the stock CDI box, but I have not read any complaints on the forums so I guess I'm good to go...

Hope this helps somebody in the future....

Cheers,

Ian