I’m Zack and I’ve been lurking around here for a bit now mostly finding myself at the site over and over again via google searches as I work through some issues on a newly had 1977 XJ-S (pre H.E.) in decent condition that’d been sitting in a garage since 1995. I wanted to share the following as I suspect it may be very helpful to someone down the road as I couldn’t find any information on the topic.
This is specifically relating to the use of a aftermarket ignition system on a Pre-HE engine that uses a fuel injection pickup in the distributor.
Here we go:
After spending some serious time fiddling with the OPUS system in the car and subsequently rebuilding the resistor pack, I found the amplifier just wasn’t doing it anymore. The transistor was toasted.
Not looking to repair the OPUS, not loving the cost of the new system from SNG and afraid of future availability of the crane system, I found the Pertronix ignitor II system which was particularly appealing as it’s just so simple. The problem here is that Pertronix says on their website that it’s not for cars with the fuel injection trigger board in the distributor such as mine.
Well, I couldn’t get a straight answer from anywhere on WHY this was the case, I called Pertronix and they didn’t seem to know and searched the web to no avail.
So, I ordered the Ignitor II, (9LU-1122A) and a .6 Ohm coil to match.
Well, it finally came in yesterday and I’m happy to report that with some timing adjustments, the car is now running again.
Why and how:
It turns out that Pertronix demands the position sensor be mounted OVER the vacuum module arm; This just doesn’t do as it will interfere with the fuel injection trigger board. So, I positioned the sensor a little bit different than instructed and much closer to the factory position (but not quite the same).
Then, I made a little eyeball timing adjustment to accommodate.
Next, we’ve the reluctor wheel which is calibrated to THEIR position for the pickup. NOT where I’ve mounted the pickup. Consequently, the points on this wheel are not in the same position as the factory Lucas reluctor relative to the keyway on the shaft.
Another eyeball timing adjustment made to compensate.
Finally, It all came back together and after a little throttle coaxing, the XJ-S came back to life.
The Pertronix system uses a pickup mounted on a metal plate that’s mounted on a plastic bracket that’s spring loaded onto the distributor. This plastic bracket is NOT snug like the factory pickup bracket. there’s about 3/32" of play to either side. Fortunately, even if it moves around, it still clears the reluctor. The pertronix coil is larger than the factory coil, a new mounting bracket must be had.
I’ve still some work to do in the way of timing adjustments before I feel comfortable giving a definitive “this can work” answer but I’m happy to say, there may be a solution for a toasted OPUS that’s less than $700.00 and doesn’t involve searching high and low for dead stock crane systems.
I haven’t even started tinkering with the tachometer yet but I can’t see why this won’t work with a resistor in the path.
Here’s a picture of the new system. The white wire grounds to the engine, the black and red to the coil. That’s it. No amplifier.