Crane XR700 help needed, car won't run

[zmayne]

I just installed a crane XR700 ignition in lieu of my old points setup. Now car will start but runs on a couple of cylinders only. I've tried moving the distributor to no avail. I have the window on the plastic disc lined up with the optical triggers.
I have the wires going to the right spots, red and yellow to coil, black to ground. The crane unit is blinking, so its obviously working, plus the car is starting but just not running right.
What could I have missed? Any suggestions from people who have done this conversion?

 

[zmayne]

sorry, forgot to mention the make of car. Its a '72 TR6...

 

[DrEntropy]

What's that 'funny lookin' reflection on the rotor just right and aft of the conductor? Bit fuzzy in the photo.

 

[zmayne]

That is some glue. I broke the rotor in half (don't ask how), so I am waiting on a new one to come. In the meantime I just glued it back together. Car was running fine even with the fixed rotor before I put the crane unit in.

 

[DrEntropy]

and you set up the pickup with the dizzy out to be sure clearance twixt rotor and pickup was adequate, yes?

I'm just tossin' out ideas here... wish it were in front of me. /bcforum/images/%%GRAEMLIN_URL%%/wink.gif

 

[zmayne]

Actually, it was installed in the car. There is adequate room to check the clearance and there is no interference between the rotor and the pickup. Is it critical to install the parts with the dizzy out?

 

[ALLAN]

Did you recheck that your sparkplug wires are right, there is a possibility that you re-cracked the rotor. There is no reason to take the distributor out to install the XR700--unless you couldnt see what you were doing with it in.

 

[zmayne]

Thanks guys. Yep, the pug wires are fine. I didn't even remove them, just took of dizzy cap. motor didn't have to be at TDC when I removed old points did it?

 

[TR3driver]

On my TR3A, I had a terrible time getting the phasing just right. The spark seemed to be happening at the right time, but was jumping to the wrong coil tower. Try moving the pickup inside the distributor a little bit (the long curved slot), then reset the timing and see if that makes the problem better or worse.

If memory serves, Crane suggests cutting a hole in an old distributor cap, so you can see the phasing.

You can also measure around the front pulley and add temporary marks for the other cylinders; then hook a timing light to each cylinder in turn to see what's happening with it.

 

[zmayne]

TR3 driver, thanks. Yes, I tried that and it did seem to make a difference. It went from just backfiring to running on a few cylinders. Did you just fiddle with the triggers location until it ran?

 

[zmayne]

And by "reset the timing," do you mean by adjusting the distributor by loosening the adjustment bolt?

 

[TR3driver]

I tried lots of things, but basically that was it : move the trigger back and forth until I found the spot where it ran smoothly under all conditions.

Obviously (I hope), when you change the trigger location relative to the rest of the distributor, you must turn the distributor back so the trigger stays in the same place relative to the shutter.
IOW, yes, reset the timing by turning the distributor body every time you play with the pickup location.
What a PITA /bcforum/images/%%GRAEMLIN_URL%%/frown.gif

 

[Brosky]

This is not a smart axx comment, but I thought that these Crane units were bulletproof and easy to install. I can see the first part but not the latter.

Is this common? Cutting a hole in an old cap to look at phasing? Seems like a lot of trouble to me for what the gain would be. Again, I'm not being critical. It's just that I was always told these were the best way to go.

 

[zmayne]

Valid point. This is probably more about my own lack of experience though, particularly with ignition/wiring, etc. I'm the doofus who had my firing order 180 degrees out after I rebuilt my engine. Tried for two weeks to figure it out, then my mechanic comes over and five minutes later the motor fires instantly... at least I rebuilt the motor properly.
So I wouldn't say it's a problem with the crane unit yet.

 

[zmayne]

oh and yes, if the car is running rough the instructions do call for cutting a big hole in the cap to see if the phasing is correct. I'm hoping to avoid that.

 

[ALLAN]

Engine on top dead center with the rotor pointing towards the #1 on the cap.(in your picture it is 180 off) Adjust your trigger with the ignition switch on and coil wire held to ground (with a gap) slide the trigger slowly clockwise (opposite distributor shaft rotation) when the light beam reaches the leading edge of a window (slot) on the shutter the coil should spark, when it sparks stop and tighten the trigger in place. -----The trigger should be pre-adjusted before you do the above so that The shutter is 1/3 from the the bottom of the trigger and 2/3 from the top of the trigger. -----Make sure your ground wire is making a good ground connection. If engine starts and running on all 6 then you can time it. Instead of top dead center you can also align your marks up where you would normally have it set like 8-10 degrees and follow the same procedure as above, that way you would already be real close to the correct timing when you start it.

 

[tr6lover]

i know exactly what the problem is, try a regular coil, it looks like you have a sport coil and this will overheat the unit. i know because i did this and talked to crane about it. the coil needs to be 3ohms resistance.
Randy

 

[ALLAN]

High performance coils work well with the xr700 and according to Crane--you might need to use a resistor, follow the procedure I outlined above and see what happens.

 

[vettedog72]

Gads!
All of this makes the $75 Pertronix a no brainer unless you can't remember to turn off the ign sw wehn the motor is not running.
/bcforum/images/%%GRAEMLIN_URL%%/devilgrin.gif

 

[ALLAN]

The xr700 is not as complicated as it sounds and it worked good for me but I switched to the Pertronix for simplicity (less wires and no box) and it has done well so far-during my engine break in period. You cant leave the ignition switch on the older xr700 units either because it will overheat the coil.