Unexplained Very Rough Running

[Nut17]

My 1963 (DPR) minor sedan has now been back on the road after 35 years in a museum and after some minor fettling have it running superbly. All indications are that the engine had a full overhaul along with total body and interior restoration prior to going on display in 1990. I have overhauled the carburetor, fitted a kit to the fuel pump - new coil, points and condenser. Valve clearances and ignition timing spot on so the 1098cc engine was until last Saturday performing perfectly. I was heading home after having it up on a vehicle lift to modify the exhaust which was rattling against the crossmember when the engine began to really lose power with really obvious serious misfire and completely came to a halt after a couple more miles. There is good spark to all four near new spark plugs, the carb is spotless and the fuel pump is delivering fuel.. The ignition timing is still set on 5deg BTDC and the fuel is 95 Octane Unleaded. I am stumped!!

[Bill_qaz]

Blocked air filter? Check compression?, possible head gasket fail.

[Nut17]

Hi Bill. Have only done 200 miles since fitting a new head gasket and having the head skimmed. I will remove the other three plugs tomorrow and perform a compression test, but the symptoms definitely point to a serious ignition malfunction. I will be having a morning coffee with 20 or so members of our local Vintage Car Club tomorrow so hopefully will fins someone who can shed some light on it.

Cheers Chris

[svenedin]

Check distributor rotor and distributor cap for cracks. The currently available condensers are often utter rubbish. Try another condenser and if this works, get a reliable condenser. Condensers from Distributor Doctor are highly recommended. I bet this is a simple and easy fix.

Another suggestion, possibly a significant air leak causing very lean running. Check manifold gasket, manifold (could be cracked), any PCV valve diaphragm and hoses (if fitted)

Stephen

[Nut17]

Thanks Steven. The cap and rotor look fine, but the condenser was part of a pretty cheap package with points. Will try and source a better quality suitable one tomorrow.

Cheers Chris

[myoldjalopy]

" the symptoms definitely point to a serious ignition malfunction"
But if, as you say, "There is good spark to all four near new spark plugs" then it is queer the engine should fail if nothing else has been mucked about with and the fuel supply is OK. Of course, it could be an intermittent issue. Stephen has mentioned the condensor but rotor arms have been known to be unreliable, even when they "look fine". Years ago, I had intermittent breakdowns caused by a failing rotor arm - the car would run, conk out, not start, then eventually start again. It went on like this for a while until I put in a new rotor - if you are getting a new condensor from the Dizzy Doc I advise getting one of his red rotor arms as well, just in case.

[liammonty]

I'd put money on this being an ignition issue given that you've replaced various items. I would get hold of good quality ones from the Distributor Doctor and replace them. I've had numerous modern coils give exactly these symptoms, as well as rotor arms. Good luck - I think this will be a quick fix though!

[Bill_qaz]

Hi Bill. Have only done 200 miles since fitting a new head gasket and having the head skimmed. I will remove the other three plugs tomorrow and perform a compression test, but the symptoms definitely point to a serious ignition malfunction. I will be having a morning coffee with 20 or so members of our local Vintage Car Club tomorrow so hopefully will fins someone who can shed some light on it.

Cheers Chris

You say good spark to all four plugs but mention only removing one, (or at least that's how I read your post) have you checked all 4 plugs are sparking whilst attached to their respective plug leads?

[Nut17]

I only removed one plug, but with old school exposed connectors on the ends of the leads I simply held the lead close to the end of the plug and witnessed the spark jumping across.
I will perform a compression test this afternoon, so will confirm a lively spark on all four plugs in conjunction with this.

[Nut17]

Good advice Myoldjalopy and Liammonty - Thanks. Sourcing quality ignition components for elderly British vehicles in New Zealand is a little challenging. Freight charges when sourcing from the UK can be prohibitive. The points I have procured came in a green box labelled Lucas with a brown fibre material for the insulated pivot, whereas the the unit that came with the condenser has a red plastic pivot. neither of them have patented ventilated contact set up.

[OGY985K]

Agree with everyone else. Get distributor Dr red rotor, condenser and points. The problem you describe is exactly what happened with my Spitfire. The Dr’s medicine solved the problem and the engine is noticeably more powerful.

[Nut17]

I managed to procure points, coil and condenser today and will have a new rotor arm in the morning.

Watch this space.

[liammonty]

Great news - fingers crossed for you!

FWIW, modern Lucas branded components aren't good. I've had good success with Bosch 'blue' coils (as fitted to old VWs so can be procured through air-cooled VW parts suppliers). Distributor Doctor sells Flamethrower coils as he says they are reliable - think you should be able to get those in NZ readily.

It's harder to know what to suggest re the other bits, though NOS parts may be the way forward. Might be worth seeing how others in NZ get hold of decent bits, if you're in touch with any fellow Minor owners?

[svenedin]

Looking forward to hearing whether this has sorted the problem. The points are common to all Lucas 25D4 distributors as used in lots of different cars so new old stock decent Lucas (or Remax) points can often be found. Just remember to clean the points before fitting as they will have been coated with something to stop corrosion. Petrol is traditionally used to clean the points but you can also use isopropyl alcohol (switch cleaner). Pitted points need a points file but not relevant with a new set. Remember not to make Rookie errors installing the points in terms of the insulating washers and order of assembly with the LT wire.

Stephen

[Nut17]

As part of recommissioning this car after 35 years in a museum, I removed the distributor and stripped and cleaned and lubricated the moving parts. I then fitted new points, and condenser and would have also fitted a new rotor arm as well, but my supplier https://classiccarparts.co.nz/?srsltid= ... bBorDSffII has not had stock for some time. The original one looks fine and worked faultlessly until last Saturday. I reckon I could fit a new set of points blindfolded after all the practice I have had over the years, so I promise there will be no "rookie" mistakes.

[Nut17]

Not much success today. The new rotor arm turned up but was the wrong one. I did however fit my rotor to a friends Minor and his runs fine with it, so I believe that that is not my problem. I will fit the new coil and condenser tomorrow - so fingers crossed.
A real smorgasbord of brands NGK Coil, Lucas Points, Bosch Condenser and Italian Made Facet Rotor Arm (Wrong One) The correct one will be here tomorrow - Also an Italian made Fuel Miser "Facet" product.

[svenedin]

Good luck. I do hope it's an easy fix. I had not realised quite how difficult it is to get parts for old cars in New Zealand. I worked in Gisborne in North Island a long time ago. I loved it there and considered emigrating. I am surprised that car clubs out there haven't stock piled things like points. If you know somebody travelling to the UK it might be worthwhile getting them to bring a job lot of ignition components back. As we've already said, the parts made by Distributor Doctor in the UK are excellent. There is one other company in the UK that makes distributor rotors and condensers and that is Retronics. The Retronics condenser is really expensive but it is the Rolls Royce of condensers and should last for many, many years. I have one in my distributor. https://retronicsonline.com/product/ret ... condenser/
Of course we are assuming it is an ignition problem and this is not confirmed yet but anyway......

Stephen

[myoldjalopy]

Well, at least you have eliminated the rotor although it could, possibly, be one of those that periodically 'plays up' and was just behaving itself in your pal's car.
While you are waiting for the new coil and condensor, it may be worth taking off the rocker cover and see if there is any evidence of broken valve springs.

[Nut17]

I have the rocker cover off at present as I still have an errant noisy tappet that has been annoying. I now have the new condenser and coil along with two rotors to choose from so should have what I need to get on with. A perfect quality set of contacts have now been installed, Unfortunately, I do also currently have some seriously debilitating health issues which limit my physical ability at present, so time frames can be a little stretched. I have considered simply fitting an aftermarket electronic ignition system to put all these problems to bed once and for all.

https://www.trademe.co.nz/a/motors/car- ... 5123858958

Or this is tempting with free shipping.

https://vi.aliexpress.com/item/10050026 ... pt=glo2vnm

[svenedin]

Sorry to hear about your health challenges and hope that getting the Morris up and running will lift your spirits. Electronic ignition is opening a can of worms and if you search you will find that the subject has been discussed endlessly. What I would say is that if you want to do it (and your health is a very valid reason) buy one of the better quality systems. The one Distributor Doctor sells is Pertronix. It's a hall-effect type that all fits in the distributor and so there is nothing to detract from the appearance of originality. Fit and forget. On the other hand, if it is just a dud condenser then a good one from Distributor Doctor really shouldn't give any issues for years.

Stephen