Which distributor?

[Binny]

I’m currently resurrecting my 2.5 pi and am unsure which distributor to use.
The car is J reg and the engine number is MG18168 HE and at sometime in the past has been converted to twin carbs with a 45D distributor. I’m converting back to pi and have a K reg pi which is a donor vehicle and that has a 25D distributor.
I’m minded to use the 25D distributor but wondered if there was any advantage to using the 45D also which coil should I use? The 25D has a ballast resistor and I presume a 6 volt coil.
Thanks for any advice.

[Alec]

Hello Binny,

there are very many distributors fitted to teh 2000 range over the years so really needs matching to your engine number. I don't have the data to hand at the moment, but if you have teh Stanpart workshop manula it should be in that.
While the ballast resistor system has some advantages of easier starting, in theory, it can give troubles and of course you need the correct starter motor for the direct feed to by pass the resistor.
Personally I didn't bother with it on my car and have not had starting problems .

If you do not have the data as to which distributor to use, respond and I will check my manual when I get to the workshop. From memory, I think P.I. distributors have less total mechanical advance. (My car does not have a vacuum advance as it is an early engine.)

Alec

[Binny]

Hi Alec, thanks for your response and unfortunately I don’t have a Stanpart manual.

Although the car I’m rebuilding was originally a pi it was converted long before my ownership to twin carbs. My donor car has been in my ownership since 1981 and its engine number is only a few hundred more than the very slightly earlier car that I’m working on. As I’m using the alternator, starter, metering unit and throttle bodies from my donor car then it makes sense to use the 25D distributor from the donor car as well.

Unfortunately there’s no spark from it at the moment so will have to check everything thoroughly although I know that the ballast resistor is pretty well shot so will replace that before anything else.

With a 6 volt coil and ballast do you know what voltage readings there should be at the coil terminals with the ignition turned on?

[Alec]

Hello Binny,

the correct distributor should be a Lucas 25D6 41236 (Stamped on the lower body, if you didn't know)

You need to be careful checking coil voltage, as if the points are not closed, all you will read is battery voltage, the circuit (As with all circuits) need to be under load condition (Forgive me if I'm teaching you to suck eggs). It's a very long time since I had a ballast system I don't remember the voltages.
With a battery voltage of 12.5 to 13, I would guess at 6 to 8 volts on the coil + terminal, points closed. Another way is to measure across the ballast resistor for 4 to 6 volts?

Good luck,

Alec

[Binny]

Once again thanks for your response, Alec.

I’m going to use the 25D distributor from my donor car. The ballast resistor is in poor condition and I’ve had to solder the terminals, also the porcelain insulator is broken so it really needs replacing.

I’ll check the voltage with the points closed and go from there.

[Binny]

Quick update.

Even though the ballast is falling apart I now have a spark - the points, despite looking perfect, would not make a circuit when fully closed so I replaced them and all good

Just waiting for a couple of bushes to arrive from Chris Witor so that the throttle bodies and injectors can be properly fitted and then I can see if it will start.

[Alec]

Hello Binny,

always good to make progress.
Be prepared for long cranking for a first start, as the manual says a fully charged battery is required.

Good luck,

Alec

[Binny]

Thanks Alec.

I’m well prepared for the long priming process and the battery is fully charged. I’ve already got fuel to the metering unit so it’s ‘just’ filling the injector lines now.

[Binny]

Further update - the engine runs

I cranked the engine over for ages with no plugs in and the injectors in jam jars before refitting them and it started almost straight away.

It runs a little unevenly but I’m hoping that can be sorted by careful setting of the throttle butterflies and the timing. Not bad for a car that hasn’t been on the road since 2001 and most of the engine ancillaries haven’t been on a running car since 1990.

It’s run out of petrol now though

[Alec]

Hello Binny,

another step but a big one, a little fetling should see things settle down.

Alec