vtdds71

Finally getting around to installing the Crane XR700 ignition kit I bought along time ago for my '72 240 (man. trans.). Engine is very stock, with OEM distributor (I think), but all emission control equipment was "lost" many years ago. Body of distributor says it's a D612-53, which doesn't match any found in the 5 shop manuals I have, so I wonder. My questions are:

1. Should the ground wire ("earth lead") from the base of the old breaker points to the distrib. base (screw next to the cap retaining clip) be removed? Instructions say to remove everything, and I'm guessing there is no longer a need for this wire, but not sure.

2. Which of the 2 available 6-slot optical discs is preferable to install? Both seem extremely tight, and it looks like, once installed, there's no removing it without breaking the plastic.

3. What is the correct timing for this car, with emission controls removed? Manuals say 5 deg. BTDC @ 750 RPM on emission-controlled engines, but 17 deg. BTDC @ 650 RPM on non-emission-controlled engines, which is pretty much what I have now. But, maybe the specs apply more to the distributor in use, than to the presence of emission equipment. Not sure.

4. I'm assuming the correct "static timing" can be set by:
a. rotating crank so that #1 cylinder compression stroke is set at the proper idle speed advance (either 5 deg. or 17 deg.) using the notches on the crank pulley and the indicator arrow on the engine block.
b. rotating the body of the distrib. so that the tip of the rotor points directly at the #1 spark plug lead wire terminal.
c. then, slide the optical sensor for the XR700 in a clockwise direction until the optical beam hits one of the six slots in the rotator disc, which triggers the "test" LED on the XR700 control unit box.
d. finally, tighten everything into these positions.

5. After this, just warm up the engine (if it starts!), and do a strobe light final adjustment to the timing. But again, which setting to use? 5 deg. @ 750 RPM or 17 deg. @ 650 RPM? Or, just "experiment" and see what works the best?

Sorry if these are repeat questions. I did a search of past threads, found a few ideas and suggestions, but still need some specific answers. Thanks for any help you can give me.

ZUL8R

I have a 73 240 and I just recently removed my XR700 and replaced it with a 280ZX electronic ignition. its very simple, 2 wires to install and it runs much smoother. my car came with the XR700 and I was never a fan of the points or the optical.

also I am at about 17 degrees for my timing with this distributor as well as when I had the XR700.

I have upgraded to an 2.8L 82 f-54 block and kept my late E-88 head with SU Carbs.

hope this helps and saves you time and trouble.

vtdds71

Thanks for your feedback. I did install the XR700 as instructed in the manual (near as I could tell), I set the timing to about 10 deg. BTDC @ 750 RPM, re-tuned the SU's, and the car is really running quite well, or at least better than with the old points ignition. I'm a little concerned as to how durable the whole thing will be, given that the internal parts are held in place with tiny little screw, some threaded into plastic. Time will tell.

Steve260Z74

If you're that concerned about longevity, do what I did and ditch the Crane for a ZX distributor.