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MG Midget and Sprite Technical - correct rotor arm

I have a 1966 sprite with a 1275 engine.It has a non vacuum distributor which I think is a type 43D.I am working my way through a misfire problem and before I change the rotor arm note that there are two types one with a longer reach than the other.Can anyone tell me which rotor arm I should order up and is there any differences with condensers between the various distributors.Can Lucas products be trusted as I was told that some distributor parts are of poor quality nowadays. Any help would be welcome.
thanks,

donald campbell
D M Campbell

Donald. The first thing to do is to accurately identify your distributor. There are two different models which came without the vacuum advance feature--the Lucas 23D and the Lucas 43D. The points, condensor, caps and rotors do not interchange between models. Model number should be marked on the distributor body. When you know what you have, you can order the correct parts for that model. A photograph would be of assistance because the two models are dis-similar in appearance.

Les
Les Bengtson

but IIRC the 23D & 25D are the same except for the vac advance, ditto the 43D & 45D. Also IIRC the 4xD has the shorter rotor arm.
The 45D rotor arm is
Unipart GRA2114
Lucas DRB104
Halfords HRA502
Intermotor 47540
David Smith(davidDOTsmithATstonesDOTcom

Donald. Over the last few years there have been some absolutly crap rotor arms and condensers on the market, they only seem to last five minutes! My advice would be to try and find a 'Genuine' Lucas New Old Stock item (however I think you'll struggle), other than that, always carry a spare.

But, from your description of the symptoms, I doubt that the rotor arm would be the cause of a misfire. Please give us a more detailed description of the problem. When does it happen, is the engine hot or cold, is it damp or dry etc etc...

Mark.
Mark Boldry

LUCAS DRB 104C
Cheers John
JOHN HALL & JULIE ROBERTS

Lucas 22 and 24 are the same general structure as 23 and 25 but have a longer body and shaft which means less wear and varaition! Jags had them fitted. I used one on my LHD midget and my MGC. The extension is in the area between the clamp and the part of the dissy where the body expands (if you know what I mean). All othe Midget parts will fit.
rob multi-sheds thomas

I had a great deal of trouble with pattern rotor arms after my MGA got on the road. All ignition parts were new, and I carried a new spare rotor arm, so I was sure that the intermittent misfire and stoppages couldn't possibly be that, but it was. Both were faulty and tracked. I have since changed to old stock rotor arms (which are harder to find these days, I'll admit) and now have no trouble. The pattern ones to be wary of, I found, were the ones where the brass blade is held on to the bakelite body with a brass rivet. Presumably the act of closing this rivet during manufacture is enough to cause small cracks. Anyway, I no longer get a Christmas card from our local recovery company.
I notice that there is now a recent advert appearing from the 'Distributor Doctor' (www.distributordoctor.com) offering 'high quality rotor arms' with a 3 year guarantee, and the GRA2101 (which may be the one you want) is £5.95. I haven't sought this chap out myself, but it may be worth looking into
Gus Gander

I will try to identify any numbers on the distributor this weekend and then try to source reliable Lucas parts. If that does'nt work no doubt "I will be back" (on this website) as Arny used to say.
Mark you asked for further info on my misfire.The engine fires up no problem from hot or cold.At anything above 45/50mph it allways feels as if something is holding it back in top gear.Occasioanlly it will misfire and blow back through the K&N filter so violently that it jumps out of gear!.On the overun it also spits coughs and backfires.The original carbs were renovated with new jets and needles,still same symptoms,I replaced them with a single big SU and matching manifold,still same symptoms.fuel pump ticks away no problem when ignition switched on and plenty of fuel comes out of the inlet pipe.Put in new Champion N9Y plugs and new leads,dizzy cap,rotor arm,condensor and points,still same symptoms.The only other unusual thing is that if I try to fit a new coil my rev counter stops working.Starts working again if I put back the old one.
D M Campbell

Donald. Some years ago (29 to be precise), I used to run an MGCGT (yep when I was 19, those were the days....!). I had similar symptoms and finally traced the problem to the distributor itself. It was worn in the shaft causing a massive dwell variation, the higher it revved, the worse it got.

There is a compant in the Midlands, H&H Ignition solutions

http://www.h-h-ignitionsolutions.co.uk/articles.htm

that will be able to help out, they stock many parts and will, if you require overhauland test your distributor. I use them quite a bit and can reccomend them.

Oh, just check all your low tension leads and connections first.....

Good luck,

Mark.
Mark Boldry

Reading the above entries has helped and confused me somewhat. Last weekend I drove a round trip of 200 miles. Every now and then the car would misfire at about 3000 rpm/55 mph for 5 mins then settle down.
Having got some spare ponts etc with the car from PO and reading the archive I changed the condenser, reset the contact gap and checked the plugs.
The screw that holds the condenser in is slightly stripped but has held.

Ran the car up and it idles well but on driving out it was very 'jumpy'. Recheck carried out and condenser screw was loose so have got it well tight now and I moved the dizzy body slightly to vary the position.

It works OK - just - the odd fire but its fine for a run to Warminster and back tomorrow.

However what are the actual parts that are needed. I also got 3 spare condensers - no numbers and 3 arms. Can you only get these from Moss etc or are they standard parts?

The other problem is the type of arms I have. The image here shows on the right the arm that I have fitted. The one on the left I dont know.

Can anyone identify these parts and give me the correct numbers for points, condenser, etc please.

The car is 1275 Mk3 midget with Vacuum advance


Dave Price

Silly question time. Is the srew holding the condenser down fitted with a washer? Could it be too lomg and snagging on the baseplate below, albeit only occasionally?

Can you take a photo of the innards of the dizzy from above so that we can see the points etc in-situ?
rob multi-sheds thomas

The one in the right of the picture used to be known as CS1 in the olden days. DSB101 nowadays I think. Basic original Lucas points set, uses condenser set DCB101.



The set on the left is the modern contact set which is labelled DSB108 in Lucas parlance, on some of these there is a small nylon "finger piece" that is moves across the baseplate as the vacuum advances and is supposed to help keep the points "clean" in service by varying the part of the contact breaker surface that is sparking as the advance changes. The self wiping set has blue plastic cam "finger" another non-self wiping set has a red plastic "finger", DSB108 is matched in service with condenser DCB104.

Lucas called them easifit because they didn't need spcial care fitting them...

Yeah right!

No chance of a fiver for every set I went to on Monday morning to get the engine running after the proud owner had spent Sunday morning (and the rest of the day) fitting easi-fit points is there I suppose? Would have been a welcome boost to the old pension...
Bill

Rob,
the threads are very worn by other PO. Will take a photo but will be delayed as other half brought forward the birth of a baby boy by a week so has sunk any chances of midget work for a while!!

Dave
Dave Price

congratulations DP !!
David Smith(davidDOTsmithATstonesDOTcom

Yes! Congrats Dave, let the Midget wait. You do have slightly more important things to do for an hour or so...

:-)
Bill

Dave. I estimate 18 months before 'junior' will want to get involved. I bought a 'Bob the Builder' spanner/hammer set for him.


rob multi-sheds thomas

I got the car to escape away from the clan as it were. Some guys asked why I bought a 2 seater car when I have a (now) 4 person 2cat 1 dog family. I said work it out for yourself!!!!!
Saying that see the image the other half took of me and the boy this morning at the unearthly hour of 0730!!!
Dave


Dave Price

Rob, It may sound stupid but why have you got a plane outside the house? By the looks of it an old biplane at that.
Dave
Dave Price

Dave, he's got to park it somewhere doesnt he?
Bill

Of course - silly me (!)
Dave Price

Finally got time to correctly identify my distributor.I was wrong, it is in fact a type 23D4 (clearly stamped on the side of it).Anyone know lucas part numbers for points,rotor arm,condenser for a 23D4?.

thanks,
donald
D M Campbell

This thread was discussed between 19/02/2008 and 24/02/2008

MG Midget and Sprite Technical index

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