msd and crane compatibility

yeuporsch · 07-22-2002, 08:52 AM

I am trying to upgrade my 72T with weber with new ignition system. Is the Crane Xr700 optical ignition system compatible with the MSD 6AL 6420/and tachometer? Do I need to go an upgrade ignition wire also? Right now I have the permatune CD unit with bosch distributor 030.
John

911pcars · 07-22-2002, 09:06 AM

In case the answer is yes, you could just purchase the optical sensor from Crane to trigger the MSD instead of buying the entire XR700 ignition unit. Or call the tech line at www.cranecams.com to ask the question.

Hope this helps,
Sherwood Lee
http://members.rennlist.org/911pcars

yeuporsch · 07-22-2002, 10:06 AM

Sherwood,
Thanks for everything.
John

chibone_914 · 07-22-2002, 10:22 AM

We offer the optical trigger to run your MSD unit. Make sure you order the 8920 tach adapter if you want the factory VDO tachometer to work.

porsche74 · 07-22-2002, 12:11 PM

Why not use a Pertronix Ignitor?

Much simpler to install and totally free from misfires caused by oil mist inside the distributor which will affect any optical pickup.

Works great with any MSD; just use the magnetic trigger wire pair from the ignition unit.

Matt Smith · 07-22-2002, 12:27 PM

Msd 6A functioned perfectly without a tach adaptor in my '72. I hear it is not always the case.

yeuporsch · 07-22-2002, 01:50 PM

I did a search on this. There seems to be a mix reaction to the pertronix ignitor. Do the rest of you guys agree? Does anybody have problem with the Crane optical trigger?

Has anyone other than Matt installed an MSD unit without using the tach adapter on an early 911T.

Thanks for all your input!

John

CamB · CamB's Garage

To followup on Matt's comment - the MSD worked fine with his tach but my 69 needed the tach adaptor (much to my chagrin).

As best as I can determine, if the tach originally ran from the coil (ie, car didn't have a CD unit - like my 69 or a 914) then you need the adaptor. If you have a CD unit already (eg, all other 911s since 1969 except the T in 69), then you shouldn't need the adaptor.

Clear? I thought not!

CamB · CamB's Garage

Ooops, we posted simultaneously.

To put it another way, I suggest you do what Matt did which is install the MSD, then try plugging the tach wire (a black/purple one) into the tach output on the side of the MSD.

If it works (which it should) - no need to buy the tach adaptor. If it doesn't, buy the tach adaptor and install.

911pcars · 07-22-2002, 02:24 PM

Tach adapter? It's need is unknown until you install the ign. system. I first installed Crane's XR700, then a Hi6S unit some years later on my normally coil-ignitioned engine (2.7). I run them in tandem and don't need a tach adapter. On the other hand, I do need a resistor as the tach reads a little higher than normal.

Per Crane's tech line, some Porsche tachs are sensitive enough to pick up the signal; others aren't so sensitive, thus the need for a tach adapter (aka, transformer).

I guess this makes things a little muddier,
Sherwood Lee
http://members.rennlist.org/911pcars

Fishcop · Fishcop's Garage

FWIW I can recommend the XR700. I added it a few months ago and have been very pleased with the results. Much better idle and better torque at lower revs.

Kevin G. · 07-23-2002, 02:50 PM

I have the Crane XR700 installed on my car, along with the MSD6AL. Bought the tach adapter as well, ran the black/purple wire straight to the MSD unit and it runs perfect. No receipt for the transformer, so if anyone needs a brand new one at a discount, let me know.

The car the above was installed in -

1972 911 T Targa, with 1970 2,2S motor and mechanical distributer. YMMV

All I can say is the car runs a whole lot better than before with points and Permatune.

Good Luck!

Todd Simpson · 07-23-2002, 04:18 PM

Why not use the Crane CD Box with their trigger? I figure if all your ignition is from one place and there's a problem you're more likely to get warranty coverage or at least better tech help. I've got the XR3000 unit with a Crane trigger, works great, but I would have preferred to get a CD unit instead. The shop that installed it swore by the Crane stuff.

Todd
'71T S motor

TimT · 07-23-2002, 05:27 PM

FWIW I installed a "Allison" optical trigger in my car about 12~14 yrs ago..... oh and then crane bought the company and it morphed into the crane trigger (XR-700)

I had YEARS of service from this trigger, I used it to fire the stock cd box, a msd (5 I think), and finally a Crane Hi-6 system.

I twin plugged my car this year , and went the electromotive route, So......

I sold my whole dialed in igntion to another fellow who loves it

( it was '67S distributor, custom wires, Allison trigger, Crane Hi-6)

Oh and early tachs ( pre 73 I guess) need a different signal from the ignition to work

a hot ignition cures lots of wber woes '-)

jpnovak · 07-24-2002, 06:12 AM

I too have a Crane 700 in my car. No more points is a good thing. I have never had a problem with it since installation. No tach adaptor necessary. I think it should work fine with either a Crane or MSD ignition box. Just use the white trigger wire to fire the box instead of your CD unit.

Jamie

yeuporsch · 07-24-2002, 10:07 AM

I was thinking of getting the crane optical trigger first and use it with the permatune CD unit which is on the car now. Then later on upgrade it to the MSD 6AL. The Crane XR3000 requires changing the old tach to a newer tach, is that correct?
John

SprintStar · 10-21-2003, 06:45 AM

Quote:

Originally posted by chibone_914
We offer the optical trigger to run your MSD unit. Make sure you order the 8920 tach adapter if you want the factory VDO tachometer to work.

What difference is there between the 8910 and 8920? Thanks!

Sprint.

ckakoliris · ckakoliris's Garage

Digging up this post from quite some time ago.

Hoping someone can help!
I have 74 911 2.7 engine with a crane fireball xr700 ignition with matching coil.

This was done by the previous owner, My tach is 1000-1500 rpm higher than it should be.

Does this sound like I need a tach adapter?