Ingnition Upgrade

Lew Plummer asks:

Has anyone installed the Jacobs ignitions system on a XJ6 -- or any after market fuel/Ign control system? I would be interested in the results.

Looking for better engine management and better mileage

I have fitted the Pertronix Ignitor module in the distributor of my carburetted 4.2 SII from 1978 a year ago. What is nice is to get rid of the need to set points and change capacitor. The Ignitor is also very neat and easy to install (I got this tip from Serge Guillermo, regional responsible for the Jaguar Enthusiasts Club in France).

I did not experience a notable drop in petrol-consumption. I did get the impression that cold starts improved slightly, (but I still have a problem with leaking non-return valves so the car needs to be cranked when it has sat for a while). Once I fixed that problem, I will install the coil "flamethrower" or something similar, that goes with the Ignitor module which has a higher voltage output, and then determine whether this improves something or not. I did not encounter any problems installing the Ignitor, it is an easy worthwile job

According to what I found in the archives, other people have fitted the Ignitor to E-types, I enclose copies of a couple of posts for you convenience. (I did not do an exhaustive search, there might be more info. if you bother to look.)

Just thought I'd do a post to let you know of my experiences in bringing my E's ignition system into the 20th century. Thanks to advice from George Cohn, Martyn Ward, Alan Mandell, Arnold Vonk and others on the list, I breathed in deeply and ordered a Pertronix Ignitor unit from British Auto USA ($99 US).

The unit duly arrived by post last week and I installed it in the car on the weekend. I took Arnold's advice and did it on Saturday. The manufacturers claim installation can be completed in 15 minutes, and in some cars this may be so. In my case, I discovered that someone had installed an XJ6 rotor button in the distributor at some stage and its rear overhang would not clear the Ignitor unit when installed on the distributor plate. So....hunt around for the correct rotor button (which incidentally, has a round shank with no rear counterbalance).

Luckily I had access to one in another "parts" distributor so no problem. I have ordered another couple as spares. The rotor button is Bosch Part number GL254 and as well as 1964 to 1968 E types, is common to Austin trucks and a few other rather ordinary British marques BTW. This rotor button presents no clearance difficulties when the Ignitor unit is in place in the distributor.

The second problem encountered (which was the subject of a recent post by Arnold Vonk) concerned the plastic water shield which fits under the distributor cap. The main function of this plastic "sheath" is to prevent moisture from entering the distibutor body proper. Unless you modify it in the manner described by Arnold you cannot use it. I have discarded it for the time being.

The Ignitor comes complete with a formed rubber "grommet" which fits into the distributor body and through which its connector leads are passed. Unfortunately, the person (idiot) who manufactured/assembled my unit at Pertronix fed the wires through the grommet from the wrong side. As the connection "spades" are fastened after this process in manufacture, I had to cut the spades off, remove the grommet, turn it around, feed the wires back through it (the right way) and re-solder the spades. As my coil is located at the front of the head on the engine on my car, this did not matter particularly, as I had to extend the leads in any case. The magnetic pulse pickup sensor is located on the points plate by the old points mounting post and locked in place by the condenser mounting screw...so it is not going anywhere. The condenser gets the "heave ho" along with the points.

The rotating unit containing the six actuating magnets which slips over the cam on the distibutor drive shaft fitted snugly and sat right down on the lobes. This is important because the rotor button locating "nipple" needs to "seat" properly into its cut-out in the distributor shaft (something the XJ6 rotor button could not do) to get the correct clearances inside the distributor cap. Unlike Arnold, I experienced no problem with clearance of the central high tension pickup "brush" with the removal of the moulded plastic water shield from underneath the cap.

As the timing would need to be adjusted, I took the opportunity to remove the distributor (bastard of a job to get at the 1/4 inch UNF mounting bolt between the block and the distributor base plate) and dismantle it and clean and lubricate the advance mechanism etc.

All of this messing around, cleaning and rewiring etc. took about two hours. In the end, I decided to dispense with the plastic water shield and its connector. As Arnold did, I may modify the shield after summer and place it back in position. The distributor in an E Type is well shielded from the elements and the Ignitor supplied grommet is a snug fit with the cap in place, so I don't envisage any significant problems with moisture entry.

So, I placed the distributor back in position, placing its base-plate adjustment in mid-position. The engine fired straight away and ran smoothly. Some rough adjustment achieved good idle and a road test with a couple of quick excursions in excess of 5000rpm revealed smoother, more powerful acceleration from rest and strong pulling right through the rev range with no flat spots or hesitation. The engine fires instantly and idles quietly. Proper timing will be undertaken this weekend. It will be interesting to see how the car now performs in terms of fuel economy and plug wear.

Personally, I am very happy with the result for the relatively small outlay. No more points and no more timing and condenser hassles ever again. Sorry about the bandwidth, but I thought this detailed coverage of the installation may help and encourage others contemplating a similar performance and reliability improvement.

Thought I'd let you know the magic solution.

I called British Auto USA this morning, spoke to Tom. Many thanks to him. He said they had had the problem only a couple of times when an Ignitor unit was fitted. He has a SII himself and has had no problems with the tach. He also hasn't connected the Ignitor lead to the ballast resistor but has gone straight to the coil as I have.

The solution: Connect the old condenser's lead to the (-)ve connection of the coil and earth the condenser. He says this takes out voltage spikes. My tacho. is wacko no more.