Well it has been a while, how time flies.
Got the engine back in in December but had no chance to really hook it all up properly until January. Cue months of rain and cold. In march I was able to go for my first run with the new rear end. I threw it over some speed bumps and it was all good, the car also drove straight, so i was classing it as a successful repair! I was really happy to be back on the road.
Now where was I up to before all of this Torsion bar tube mess. I was running in my newly built engine. Now I wasnt fully happy with how it had been running before the tube failed the engine seemed to stumble a lot and stall and now it seemed worse than ever juddering as I was driving along. But working lots of overtime to pay for tube repairs and garage floor tiles, I didnt have much time to look at it. I still had doubts about the mixture settings and the twin plug ignition system. In the end I wanted a second opinion so I took it to Johnny at UnitEleven in Warrington. Fortunately it was a nice sunny day and he worked on it outside. He got it running much better with some mixture adjustments and throttle body adjustments but it was still stumbling. I still wasnt happy with it. A timing light showed that it was misfiring on both banks, randomly missing sparks. Another issue he spotted was that the charging system wasnt putting out enough volts, we were only seeing ~12.8V at the one battery I was running, so no wonder I have had issues with flat batteries and slow cranking over the years.
So first thing I looked into was the charging issue as I thought that would be easiest to fix. I know I have a SEV Marchal alternator, and a lot of googling later I found out that your regulator and other gubbins in the engine bay must also be SEV Marchal for the output to be correct. My regulator and gubbins are Bosch. Somehow over the years this car has ended up with a mis-matched arrangement and I'm told this results in the system outputting around 0.7-0.8V lower than it should. Marchal regulators are now hard to get hold and the wiring/plugs etc are different and I dont want to start messing around cutting up my loom. I looked at fitting a modern unit but most of them appear to be made for later engines and wont fit my fan housing and/or are very expensive. So Im on the look out for an original BOSCH unit.
In the meantime I have bough a second battery and installed it. I know that many think this is unnecessary extra weight but ive had enough issues over the years with slow cranking on the one battery and it dying or nearly dying when I have had to stop and start the engine a few times in one day that I think its for the best. It may be more to do with the charging system than the fact I had one battery but Im thinking its better insurance. It cranks and starts so quick now! Johnny also said it would be better to have it so that sealed it.
After this came the Ignition problems. I spent 2 weekends trying EVERYTHING I could think of to cure the ignition issues without success. I swapped in/out/over the CDI boxes, coils, leads, plugs, checked all the earths and battery cables, re-routed everything for interference issues tried to fit shielding, took the distributor to bits and cleaned up every contact, I tried everything. It kept misfiring on BOTH banks. Eventually I contacted Johnny at Classic Retrofit and he had the answer. He told me that if running an MSD magnetic pickup to trigger CDI boxes you have to reverse the polarity of the pickup. I.e. to wire the pick up opposite to the MSD diagram and run the +ve wire to earth and the -ve wire to the CDI box. I flipped the wires in 2 minutes and there it was running perfect. On the one hand I was absolutely delighted but on the other very frustrated at this whole episode.
Now that im getting proper ignition the revs are much higher at idle so the throttle bodies the timing will need re-setting again! Oh the joys. So thats my next job. I do feel im very close to a properly running engine now! I might even try and get the speed switch fuel cutoff to work if im feeling brave!
Another thing I have invested in is a genuine Marelli Jaguar 12 plug distributor cap as the repro caps that come with all the aftermarket distributors like mine really do look crap quality
