The Triumph Dolomite Club - Discussion Forum

I don't know if any other members have had any problems with their distributor caps but if you have got one recently check it out. I have had two supplied by a well known classic parts distributor, both with the same problem on my Dolomite 1300. The rotor arm is cutting into one or more poles because they haven't been machined or moulded centrally. Small shavings of metal are produced and spread around under the cap that can cause tracking and ignition problems. This is not just a problem with the OHV cars. I took the car into my local classic garage for help to try to resolve my long term recurring problems of misfiring. They found that the Luminitions electronic ignition was faulty. Looking for the fault they fitted a new cap and this cutting in problem was discovered so they replaced it only to find this one is the same. They then went on to find that a TR6 that was in for misfiring on the same day had the same problem. Further to that they had recently worked on a sprint that had melted a hole in the cap (a member) and this was eventually diagnosed as being caused by the same problem.

As they had nothing in stock or wanted to get any more caps from their well known supplier I am having to make do for a while. I have eased the worst pole a little and the car is running sweeter than ever now but I have a cap on order coming later this week. The garage owner recommended that I try the Distributor Doctor and he has told me today that he has original old stock Lucas caps in stock, and also has his own which are a little more expensive that he gets made in the USA. One of these is on its way to me for about £25.00 delivered. Ok five times the price of a "Lucas" or Intermotor but guaranteed quality and should last for years.

By the way the garage, Yorkshire Restorations, did all the work swopped plugs, caps, leads, checked out fuel system, cleaned lines, re-tuned carb, split the engine earth so it didn't go direct to the battery, and put back on good quality points and condenser all for free, including no charge for the parts used. I cannot recommend them enough if your in the Yorkshire area and need mechanical work or restoration doing.

Bob, I fitted a Britpart dizzy cap (bought from Rimmer Bros) to the Sprint dizzy on my 1850 and it seems to be fine. The car's not running well at the moment so I'll need to take a look at my cap and see what it is like.

Going slightly off topic, I came across a couple of old 6v coils in my spares collection and you're welcome to try them if you're still having coil issues. I can bring them to the next meeting.

Hi Dave

Thanks I will take those coils Dave for back up. Although the symptoms seemed to be yet another coil failure the garage thought it couldn't be again. That's why they went into everything starting with the fuel system then, plugs leads, cap but the problem got worse and the car was missing under load, OK cruising but a drop in power. Then a discussion was had with his engineers and one came up with the same problem with coils failing on an mga that turned out to be engine earth, so we decided to mod mine. It was whilst doing this that the second cap was found to be the same as the first, and coincidentally the TR6 that had just come over from Manchester had the same issue. With the cap off I was cleaning out the shavings from the distributor and found the electronic control unit was red hot so called them over. Out it came and the plate holding the unit on was black from earthing out. Points went on and a good test drive later giving it stick no misfire. Today did about 40 miles and no misfire car running smoother and pulling better than i can remember and wanting to cruise at higher speeds.

Hopefully its the end of this, its plagued this car intermittently since the ignition system went in, coils running red hot and failing, correct coils fitted, and engine misfires cruising at 50/55. If its not cured there's nothing left. Its had cheap and expensive coils and I don't understand if its coils taking out the ignition or the other way round. I am sure Jerome will know. Certainly reluctant to put an electronic unit in again. This luminition unit failing in the way it has is apparently unheard of.

I took a look at the dizzy cap on my 1850 and it looks to be fine. The Britpart kit that I use could be worth a try and eliminate the issues associated with points. Mine hasn't given me a moment's bother since I fitted it about 4 years ago.

Doesn't look like they do the britpart cap now and the one they do looks like and is priced similar to mine. I have been told that all the caps on sale now regardless of brand are coming out of the same Chinese factories. This would in some way explain the reason for different models all having the same problem

Again, going slightly off topic, have you considered hooking up an oscillisocpe to your car? It might help you to get to the bottom of your problem if you haven't already cured it.

New distributor cap has arrived from the Distributor Doctor and it is far better quality than what's about at the moment. Thick plastic body that fits snug on the distributor with no moving about like the others and it has brass posts rather than what I assume is aluminium.

Although by easing the offending pole on the old one that seems to have stopped the arm cutting into it this new one does seem to give a smoother tick over. Not driven it yet if get time will pop out this pm but so far defo worth the extra money.