The Crane XR-i ignition system...
The Crane XR-i ignition system (PN 750-1700) module replaces conventional breaker points on just about any Ford V-8 engine with a single-point distributor. The unit uses a Hall-effect sensor to detect the lobes of the distributor points cam. The module itself is shown at right with the adapter plates and all the other included pieces of small hardware needed for installation in an otherwise stock-appearing Ford distributor.
Electronically-triggered distributors are nothing new in the automotive world. So much so that these days we're still surprised at the number of older Mustangs using points and a condenser as a means of getting the spark to an engine's spark plugs.
When it comes to vintage Mustangs, upgrading to an electronic ignition within the confines of a stock-appearing distributor has been an option for enthusiasts for well over a decade. So if you haven't installed a Crane XR-i points-conversion ignition or something similar in a car that's driven on a semi-regular basis, our only question is what are you waiting for?
We can see the reasoning for keeping the older-than-dirt points and condenser in the distributor of a show car that's only driven in and out of an enclosed trailer, but you should put this sort of upgrade on the short list of the first two or three things to do to an otherwise unmodified vintage Mustang.
The Crane XR-i is among the numerous options available to get a distributor out of the stone age. After installing one in a 351W's stock distributor in a little over an hour, we can report it's worth the effort.
Several notable features are contained within this matchbook-sized module, which fits any single-points Ford distributor built between 1957 and 1974. Of course, the biggest advantage with the XR-i is its maintenance-free nature. Other advantages include the unit's urethane seal to protect it from oil, dirt, moisture, vibration, and heat, and its relatively easy installation, both physically and electrically since its two wires simply connect directly to the ignition coil.
Finally, as an added feature for more radical engines, the XR-i's built-in rev-limiter with a 4,000-8,000-rpm range provides a bit of extra engine protection in the event of a missed shift.
1 While removal of the original...
1 While removal of the original points-plate assembly is required, installation in a Ford distributor is still relatively easy. The included step-by-step instructions are clear, easy to follow, and logical provided you follow them closely and with a deliberate approach. We had the 351W in our '69 Mustang up and running with the XR-i in just over one hour, and that included photographing the process. Here, we've already removed the distributor cap and rotor. We also removed the four plug wires from the passenger-side of the engine so we could set the cap and wires (and coil wire) completely out of the way. Then we began the procedure by unscrewing the stock points as shown.
2 Next, unscrew and remove...
2 Next, unscrew and remove the condenser.
3 The points are removed...
3 The points are removed from the distributor, and along with the condenser, can either be stored or thrown away. Ours were recently replaced so they could work on another car, otherwise, old points and condensers can be tossed into the dumpster.
4 The original Ford points...
4 The original Ford points plates should be replaced by the Crane plates. This distributor had an E-clip holding the top plate in place. Removal allows the top plate to come out.
5 Remove the vacuum advance...
5 Remove the vacuum advance by removing the two screws from the distributor body. The arm of the vacuum advance is connected to the top plate; remove it by gently prying it upward from the tab on the plate. The diaphragm can then be completely removed from the distributor. Although the diaphragm isn't reinstalled with the Crane ignition and isn't needed, it's probably still a good idea to hang on to it and the other pieces that come out of the distributor body.
6 With the vacuum advance...
6 With the vacuum advance out of the way and the points and condenser removed, remove the top plate from the distributor housing.
7 Carefully remove the two...
7 Carefully remove the two screws that hold the original bottom plate to the distributor body. Be careful not to round the screws with the screwdriver bit. If they're too tight, use a spray lubricant to help loosen the screws.
8 With the two screws out,...
8 With the two screws out, the bottom plate can be removed from the distributor body. We're now ready to begin installation of the Crane module. Retain the original plates, since replacements might be difficult to find without buying another distributor.
9 To prepare the plates for...
9 To prepare the plates for installation, press the supplied nylon center ring into the bottom ring, making sure it's fully seated. It's a relatively easy fit and doesn't take much pressure to mount.
10 The four supplied, nylon,...
10 The four supplied, nylon, button-like slides are next pressed into the bottom side of the top plate. Press fit them into the four non-threaded holes in the top plate, as shown.
11 The next step is to join...
11 The next step is to join the two plates together on the nylon center ring. Be sure the top plate rotates smoothly. If it doesn't, polish the inner diameter of the top adapter plate with an emery cloth. Our pieces moved smoothly without polishing work.
12 The Crane adapter plate...
12 The Crane adapter plate mounts to the distributor body using the same holes as the original plate. The Crane plates are direct replacements for the stock Ford units.
13 The assembled adapter...
13 The assembled adapter plates and center ring drop into the distributor body and align with the holes in the distributor body. Align the two small cutouts in the top plate with the mounting holes in the bottom plate. If they don't align, flip the bottom plate over and they should line up.
14 One of the two supplied...
14 One of the two supplied 8-32 screws that hold the adapter plates also retains the jumper wire. In the order shown here, large ring terminal of the jumper wire, plastic washer, and aluminum spacer, assemble these pieces together on the screw...
15 ...and place a small dab...
15 ...and place a small dab of thread-lock compound, such as Loctite, to the screw before installation.
16 Next, install the screw...
16 Next, install the screw with the jumper wire into the distributor body. Install the other screw on the other side of the distributor body with the same parts (minus the jumper wire) and thread-lock compound. At this point, we're almost ready to install the module itself.
17 Before installing the...
17 Before installing the module, set the rev limit on the unit's built-in limiter by using a small Phillips-head screwdriver to rotate the potentiometer to the desired setting. Semi-circular indexes form an arrow which points to the desired setting. We set our limit at 6,000 rpm; plenty for a healthy 351W street engine but not enough to hurt anything. The potentiometer rotates 270 degrees with full counter-clockwise at 4,000 rpm and full clockwise at 8,000 rpm.
18 Route the module's two...
18 Route the module's two wires through the hole in the distributor as shown, and apply a liberal coating of the supplied thermal grease to the underside of the XR-i module.
19 After coating the module,...
19 After coating the module, set the unit into place being careful not to pinch the two wires coming from the module that go outside the distributor.
20 Install the supplied 6-32...
20 Install the supplied 6-32 Allen-head screws to secure the module, using one to hold the other end of the jumper wire in place. The flat side of the ring terminal should contact the module's mounting ear. Push the module as close to the points cam as possible without touching the points cam lobe (the XR-i uses the points cam to pick up ignition timing as the unit doesn't use a shutter wheel). Once set, securely tighten the two Allen screws to hold the module in place.
21 Here's the XR-i installed...
21 Here's the XR-i installed in a stock distributor and ready to go. Simply reinstall the rotor, cap, and plug wires to complete the physical installation of the module.
22 Connecting the module...
22 Connecting the module to the coil couldn't be easier. We crimped an eyelet connector to each of the two wires and connected them to the coil. The black/yellow wire from the module goes to the negative side of the coil, and the black/red wire goes to the positive side of the coil. Once everything is buttoned-up and the engine is running, check ignition timing with a timing light and adjust as necessary.