The Triumph Dolomite Club - Discussion Forum

Went for a drive today and the car had a chronic misfire across the rev range and across a range of throttle openings - tacho was fine all the time so assumed problem was on the HT side.

I took the distributor cap off and was dismayed to find a nice film of silver metal dust on the inside and all four contacts were quite burnt on the edge. The rotor arm has not been making contact so I assume the metal deposit is caused by the arcs and sparks. This was a new cap last year, along with new rotor arm and new leads and everything else on the ignition side - leads, cap and rotor arm all from the same supplier, not from the Distributor Doctor who quote "couldn't get stock of decent quality caps". The cap is taller side entry one with plug in leads. I noticed that it was poorly moulded around the 4 contacts and also that they were - or appeared to be made of aluminium and not brass. Anyway I cleaned it out and tried again. It was much improved but was still missing.

Returned home and refitted the old cap, rotor arm and leads - the shorter "original"? with screw in leads. This is well worn as the previous owner fitted electronic ignition and the rotor arm sat too high so "shaved" some of the contacts. Car now runs OK and only coughed a couple of times.

I want a new replacement as my original is not in the best shape - though works better than the "new" one. Question is what is the best cap to go for? Do I go for a new GDC134 (original type) and hope the quality is OK or is there a better alternative.

I am running with points and a condenser - they are good genuine N.O.S. Lucas orange box items and swapping them makes no difference. Hot swapping the coil makes no difference either. Leads are new with no sign of tracking and no tell tale "ticking" or visible blue streaks in the dark, so I am convinced it is the cap.

One other thing, I do not have the RTC316 spark guard - is it essential with the shorter cap?

Thanks

Roger

_________________
1975 Sprint Man O/D in Honeysuckle Yellow
1971 Stag Auto White

Too many cars, too little time!

Hi Roger.

When I purchased my Sprint there were countless spare caps in the boot and I know the quality of some of the aftermarket caps can be 'wanting'.
I managed to find a genuine Lucas 44D4 cap on ebay - they do come up, but do command a significant price.

I purchased points and condenser from the DD, and had the same response regarding the caps from him.

I know Austin Ambassador caps have been used in the past - this may be the one you have? I imagine the quality issue would affect them too now though, unless you can find NOS.

For such a routine service part, it is disappointing that the quality lets us down again. I don't know if the Robsport caps are any better - they don't tend to sell any rubbish, so may be worth a go?

Kind Regards
MC

Yes...... the new Lucas stuf..

Caps made from recycled barbies and luchboxes. Put your finger on the dizzycap while running and it starts misfiring.

You can hate Rimmers and love Robsport but these both are selling the same caps. There's one (Chinese) manufacturer that makes all current available Lucas parts that aren't actually Lucas. Just crap in boxes with the letters L, U, C, A, S, on it.

So when you buy a new cap, whatever box is around, also the 'new' brand Remax, it's all the same cap. Try to find a NOS genuine Lucas one or a good used one that will solve all your problems. When buying a new one just find the cheapest seller..

Jeroen

Thanks Matt and Jeroen - you pretty much just confirmed my suspicions and thoughts. I will keep an eye out for a new old stockGDC134 or maybe a new old stock Ambassador one - GDC142.

Another problem is there is a N.O.S. Unipart GDC134 on ebay at the moment. The box says GDC134 BUT the picture of the cap is top entry? which I don't think can be correct, unless anyone knows different.

https://www.ebay.co.uk/itm/143790341690


Also is the spark guard really necessary?

Thanks

Roger

marshman wrote: ↑Sat Dec 11, 2021 1:37 pm Thanks Matt and Jeroen - you pretty much just confirmed my suspicions and thoughts. I will keep an eye out for a new old stockGDC143 or maybe a new old stock Ambassador one - GDC142.

Another problem is there is a N.O.S. Unipart GDC134 on ebay at the moment. The box says GDC134 BUT the picture of the cap is top entry? which I don't think can be correct, unless anyone knows different.

https://www.ebay.co.uk/itm/143790341690


Also is the spark guard really necessary?

Thanks

Roger

Don't think the cap in the link is the right one, no matter what the box says. I've been misled in the past buying bits that LOOK right in the pic, only to be fooled by a "file picture" of a generic whatever-it-is. But I don't think thats the case here, the carpet background is a giveaway of someone selling a single part and what you see is what you will get!

I've run cars and had experience of many more, both with and without the "spark guard" personally I can't see it makes any difference at all, even though you'd think it would, if not for it's short arresting qualities, then at least for making the cap fit tighter! But no, not even that, the spring clips take up the slack.

Steve

Thanks Steve, shan't bother sourcing a spark guard then.

Roger

http://oldtimer-schweiz.ch/oldtimer/

I had some luck here but don't know he has any left.

Jeroen