V-12 ignition system upgrade

[Claudio]

Hello,
another issue related to the ignition system upgrade for the V12 engine goes to the kits offered by REOPUS and SNG Barratt. So question: does anyone know the difference/advantage between them?
Thanks, all best!
Claudio
BTW: reading other posts from this forum I realized I am suffering same problem of re-starting engine when hot.

[SESH]

I have fitted the SNG Barratt unit and it works fine.

[MarekH]

Dear Claudio,

If your ignition works, then leave it be.

If your ignition has failed due to overheating, you can use a bag a frozen peas to cool it down to diagnose whether the overheating was to blame.

Next time you simply have trouble restarting when hot, floor the accelerator.

kind regards
Marek

[Heuer]

One more thing to add to the toolkit!

[Woolfi]

I have mounted a used ignition system from a XJ12 HE, which has been much cheaper the the new system from Barratt or Reopus. It works fine since 8 years.
The "chip" inside the amplifire box AB14 can be bought in internet up from 12 pound, if failed.
Regards Wolfgang Gatza

[vee12eman]

Hi Claudio,

Firstly I respect Marek's view as he knows the cars very well, however, if the ignition fails away from home, you are unlikely to have a handy bag of fozen peas! I view of the fact I wanted peace of mind, I decided to upgrade to Reopus during the restoration, despite the fact I did not even know whether my original Opus worked or not (the car had been a non-runner for all my ownership).

I researched both SNG and Reopus, before selecting Reopus. I have nothing bad to say about the SNG version, but I discovered that the Reopus version came from someone passionate about V12 E-types, who was constantly updating the design, offered free upgrades from one version of the system to a later type in many cases and knew the cars intimately.

Both through the website, then later email and eventually over the phone, I was able to talk to Dave Curry in New Zealand, the original designer/manufacturer. It so happened that for various reasons I had a mis-match of parts with some from my original car, some from an XJS. Dave understood the exact differences, described them and gave me the solution to my problem, without me having to source expensive new parts (I had to wire in a resistor worth a few cents). He received my original parts, assessed them, modified and tested them, returned them to me and was on hand for me to phone/email him when I had questions regarding the fit. Talking to him I discovered, purely by accident, the solution to a couple of other issues regarding the car, not directly related to the ignition system. His website discusses several aspects of the cars and he clearly knows what he is about. Had it not been for the issue of mis-matched parts, it would have been, like the SNG system, a purely bolt on solution.

I started restoration in UK, but finished after my migration to Australia, had I still been in UK, I think I would have bought from SNG, but, faced with mail order in either case, I chose to buy from the guy who had best support for his product. In no way would I denigrate the product from SNG, but I believe that it would be unreasonable to expect the same level of support from the excellent counter staff and while the help is almost certainly available, they deal with thousands of different product lines, whilst Dave deals with just one. I doubt very much they would have diagnosed my mismatched components as Dave did, over the phone, sight unseen. I don't know what the support is like from the UK based arm of Reopus, but judging from the website and knowledge shown there, I believe it would be just as good.

Regards,

Simon

[MarekH]

The reOPUS website does indeed have a wealth of information about the original OPUS ignition systems and is well worth a read for anyone with a v12.

My favourite method of solving problems is to do a thought experiment and use that to solve the problem backwords (because you already know what the correct answer is as opposed to not knowing what the fault is). In this case we already know that an overheated OPUS can fail, so why not start the car and rev it (just to make sure you know that the ignition works), then disconnect the OPUS, put it in the oven at 80'C for an hour, take it out, plug it back in and restart the car.

If it stammers or fails, let it cool down and retry - you have found a fault (but maybe not the only fault).

If it fires up ok, you can either repeat the test or use the same approach to then test each of the coil or ballast in turn.

Effectively, it's just the bag of peas trick backwards, without your getting stuck out on the road.

In general, after 40 years, these cars can often have very brittle wiring which may not have good continuity. My car's previous owner used to always start the car with a booster pack, claiming it was the only reliable way to make it work. When I looked carefully at the wiring coming out of the ballast resistor, I found one cable hanging on by just two strands of copper and solved the hard starting problem by fitting a new connector.

kind regards
Marek

[PeterCrespin]

In this case we already know that an overheated OPUS can fail, so why not start the car and rev it (just to make sure you know that the ignition works), then disconnect the OPUS, put it in the oven at 80'C for an hour, take it out, plug it back in and restart the car.

Excellent strategy Markek, with one teensy weensy flaw-ette:

You are fortunate in having sole jurisdiction over your kitchen. For those of use who have to negotiate oven access, one false move could result in a metaphorical bag of frozen peas being applied to one's privileges, as it were...

True, there are those who like to live dangerously and risk an oven episode during their significant other's bingo night / Am Dram rehearsal / choral society practice [delete according to Hyacinth Bucket status]. Even so, the successive heat-testing of ignition components and de-smogging the kitchen plus liberal application of Febreeze to ground floor soft furnishings could result in a weeks-long diagnostic regimen.

However, my ReOpus purchase turned out to be initial misdiagnosis of a fuel crud issue, so what do I know? I console myself that it would have needed a new amp anyhow before long. :-)

[jumanor54]

Hi Claudio
I fitted the Re Opus unit to my car 2 years ago and it has made a tremendous difference to the performance and economy of the car. I should say however that there wasn't anything wrong with the original unit so long as you re-mount it from the V of the engine to the cross bar under the header tank which keeps it cool.

[Woolfi]

"I fitted the Re Opus unit to my car 2 years ago and it has made a tremendous difference to the performance and economy of the car. I should say however that there wasn't anything wrong with the original unit."

If there was only a small difference in performance and economy, the old Opus system has not worked correct. A normal spark is a normal spark. If the old system was not in good condition and the sparks have been more or less weak, then it would have been possible, that the performance and mileage was going up.

When I have changed from Opus to HEI i my 5,3 years ago, I could not feel or measure any difference.

Regards Wolfgang Gatza

[42south]

[quote="Claudio"]Hello,
another issue related to the ignition system upgrade for the V12 engine goes to the kits offered by REOPUS and SNG Barratt. So question: does anyone know the difference/advantage between them?

Hi Claudio
The difference between the systems is that Reopus tries to replicate the original opus amplifier circuitry with more modern heat resistant components.
The SNG system takes the later upgraded solid state amplifier as used in the later V12 cars, and also supplies a rebuilt later distributor with the upgraded internals. This is known as the HEI system.
It's main advantage is solid state chip electronics with no susceptibility to high temp breakdown, and supposedly better hot starting. I find ,as Marek says , that hot starting is best accomplished by holding the accelerator to the floor until it fires.
As woolfi says you can pick up a second hand HEI system from a wrecker, and the chip is on Amazon or eBay very cheaply.
I have tried both systems, and my vote is firmly in the SNG camp.

[BriWillo]

Hi Gents

I run a 1971 V12 E Type coupe (owned 30 years) and replaced the ignition system with an upgraded one from JAG SPARES (Norfolk, UK) about 5 years ago - I believe that they supply the REOPUS system as do a number of specialists (or they used to do, things may have changed now) such as Martin Robey. I have only covered 3000 miles in that time with the car running well until now when a severe misfire has developed and it is not fuel related.

[From their web site today: 'Upgrade your Opus ignition system with this modern electronic conversion, still looks original but reconditioned distributor fitted with new pick up and Original Opus amplifier casing fitted with modern electronic amplifier. Supplied with coil and ballast resistor'].

We have checked the wiring and connectors to the amplifier and resistor which is ok. Is it possible to test each component of the system to determine which is failing? Also is it possible to buy each item separately rather than a complete new unit (not asked this of Jag Spares or anyone else yet)? Assuming this diagnosis to be correct, do I have a legitimate claim against the supplier of the new unit purchased 5 years ago - despite the low mileage I imagine it is out of warranty?

If I have to replace again and after reading some of the analysis on this subject on this forum, I am thinking of going for the SNG Barratt system instead.

Appreciate your comments and advice. I am not doing any of the work myself

Brian

[SESH]

Hi Brian,
I have the SNG Barratt system on my V12 OTS. It works very well.
However, I would advise asking them to put longer wiring leads on the amplifier and mount it on the picture frame behind the radiator, as it will be much cooler there. One of the problems with the old system was the heat that is generated in the middle of the V on the engine block. It tends to fry the circuit boards. However, when mounting it on the picture frame (I used a header tank mounting bracket) don't forget to add a dedicated earth to the original mounting hole/bolt as the whole amplifier is earthed through the bolt hole not the exterior casing.
Good luck.
Mike

[mgcjag]

"Legitimate claim"......on a 5 year old psrt that youve used for 3k miles......no way.....Steve

[BriWillo]

Thanks Steve,

You give me the obvious answer that I expected. I guess you can appreciate my frustration that an upgraded ignition system that has covered this low mileage should apparently fail and, in particular, that at this time I do not know which component is the cause of the problem. Many thanks, Brian

I should give you all an update which is that the problem with my V12 E Type, initially attributed to the electronic ignition system (a Re-Opus system that was installed 5 years ago) turned out to be nothing to do with the said system. The fuel filter (adjacent to the spare wheel in the back of the car alongside the fuel pump) was sucking in air so the fuel was aerated. I have replaced the fuel filter and had the fuel pump checked which is working fine. However, I may well upgrade my original fuel pump with something more modern noting the electronic versions available from SNG at about £170 ref their web site.

As discussed, it is not easy to check the electronic ignition components individually although I cud have sent the Re-Opus amplifier away to be checked, but not necessary in the end. All wiring and connectors were checked and replaced as required, likewise all plugs dirtied by the incorrect fuelling. I also replaced the dist cap and the rotor arm for good order (did that as first option) and, whilst they were not torn, I replaced the diaphragms in the carbs as they were looking fragile. All these replacement parts being inexpensive so made sense. I am not sure how often the dist cap needs replacing but it seems to be vulnerable to heat.

Reading this forum, there is no consensus as to which of two most common electronic ignition systems are best, the latest Re-Opus or the SNG Barratt option. Probably both are adequate (if not equivalent to a modern system) and a good improvement on the original Lucas Opus system.

Obviously, I am not changing my Re-Opus system of 5 years ago now when I do not need to. In the final analysis, the above work and particularly the replacement of the fuel filter which has probably been defective for some time, I now have the car running BETTER and SMOOTHER than it has done for a long time. It starts on half choke instead of full choke and it starts well when hot.

Many thanks for the comments and advice given. Brian

[lowact]

Reopus versus SNGB ignition systems, a high level objective (=simplistic) design comparison. Due to age and poor maintenance a system that has a higher design capability may perform worse than a less capable design that is newer.

The three ignition system requirements: spark reliability, spark intensity and spark timing.

The original system Lucas Opus, was deficient in all 3. Reliability was poor due to the electronics susceptibility to heat. Spark intensity was poor at high speeds due to the relatively small single coil being overworked , worse with aftermarket coils that had the wrong impedence. Spark timing was poor because it had to be, when Jaguar was obliged to use carburetors instead of fuel injection a compromise was made, for improved drive-ability timing was vacuum retarded, despite this causing engines to be slightly hotter and less efficient. So Lucas Opus relative score = 0/3.

ReOpus, particularly the latest with optical sensor, has modern and vastly superior electronics, reliability should be 1st rate. Expertly paired with modern more powerful coils, spark intensity should always be more than adequate. But using the original distributor means timing is still retarded. So ReOpus relative score = 2/3.

Jaguars replacement of the Opus system was the Lucas CEI system (CEI = Constant Energy Ignition). Reliability was improved by different electronics are by relocating the amplifier. Spark intensity was improved by using dual coils, later by using modern more powerful coils. With efi, spark timing was able to be improved without impacting drive-ability, by changing from vacuum retard to vacuum advance. So Lucas CEI relative score = 3/3.

There are actually two versions of the SNGB ignition system, the purchaser is free to choose the one they want. In both cases the electronics are just the Lucas CEI electronics shoe-horned into an Opus amplifier housing so reliability is same as for the CEI system, more than adequate. Also in both cases the included coil is fairly ordinary imo, for the price they could have done better so, since this is my assessment, they get no points for spark intensity. The difference between the two SNGB ignition systems is, one enables vacuum retard, the other enables vacuum advance. So, SNGB retarding ignition, relative score = 1/3. SNGB advancing ignition, relative score = 2/3.

[MarekH]

I'm not sure I agree with all of your analysis Colin.
Your comments about spark timing, carburettors and fuel injection are not OPUS related.

OPUS cannot be penalised for spark timing because this is dictated by the distributor and is the same for all three ignitions. All three are equally bad and they share the same distributor build quality, the same little metal weight technology for centrifugal advance, similar vacuum hoses, solenoids and diaphragms - indeed the XJS has even more of this than the 1974 emissions etype. The spark timing on all of these is never going to be better than +/-5'. The OPUS "problem" is that the components inside are not spec's for high temperatures and 40-50 years later, that has finally come home to roost.

I don't think I'd score any of these systems highly by modern standards, as all cars these days are fitted with mapped ignitions. If the belt arrangement on the front of the v12 did not have so many variations, then a system similar to either Ray's EDIS implementation or a simple ignitor box run by Megajolt would trump all of these options.

kind regards
Marek

[JackieV12]

So did anyone on here end up purchasing the DAB conversion kit from SNG Barrett? If so, how did it work out for you? I've had problems with the ignition starting after the engine is hot ever since I bought my car new just off the boat in 1973. Have tried lots of other things over the years with no luck (including a relay bypass). Really hoping this is the solution.

Happy to hear about anybody else's experiences with the SNG conversion kit and/or ignition problems.

Thanks, John

[abowie]

Can't comment on the SNGB offering but I'm about to install a Pertronix Digital HP box on my 1975 XJS.

[JackieV12]

Thanks, Andrew. Let me know how it goes. I also have a 1965 Mark 10 but her ignition has always worked well.

John