Lucas 43D stripdown

[69S4]

Anyone know how to get the advance weights out of a 43D? I've got the unit out of the car and the points plate off but it's not obvious how to remove the cam and weights. There seems to be some sort of plastic collar holding it in place but I'm reluctant to start applying force until I have some idea what I'm doing.

[oldelanman]

Hi Stuart,
I think the 43D/45D is very similar to the 23D/25D, if that's true the cam plate is secured to the shaft by a single screw down the centre so you remove the advance springs and the screw and the plate should just lift off - unless of course it's siezed. With the springs removed the cam plate should turn freely on the shaft, if not maybe it needs some WD40 to free it off. Once the cam plate is off the weights just lift off their posts.

This article may be useful......http://simonlacey.com/pages_new/content/distributor%20rebuild.htm

Hope this helps.
Regards,

[69S4]

Hi Roger.
Thanks for the rapid reply. Unfortunately there's no central screw in my distributor, which is what's stopped me. Below is a pic of what it looks like.



The reason I've got this stripped down is because of the advance weights. They're marked up as 7 degrees (= 14 degrees of crank angle) which is nowhere near enough for my Stromberg engine, and measuring with a protractor shows that to be about right (7.5 degrees on measurement). With 9 degrees static I'm only getting 23 or 24 degrees total advance rather than the 33 it should have. Since fitting it (the old 23d body cracked) the car runs ok but is definitely less lively at the top end.

I wanted to see if there was anything I could do to improve things (file?) but I'll need to get the weights out first. The distributor itself is in v good condition - prob less than 10k miles from new so it doesn't need a rebuild and these are the weights that were in it from new (bought from Paul Matty).

[oldelanman]

Hi Stuart,
I see your problem - no idea what holds that on - maybe a snap ring ? Clearly the 23D and 43D are different. Looks like Paul Matty supplied you with a distributer for an SE or Sprint which, according to the workshop manual, would originally have had a 23D with 14 deg max advance.

You also have a pm.

Regards,

[billwill]

That appears to have been centre-popped to lock it. Very odd.

See if it comes off from the other end, See if you can get the gear wheel off. I believe they are held on by a pin through the shaft.

[billwill]

Lots of stuff I never knew before about distributors.

http://www.teglerizer.com/mgstuff/lucastuning.pdf

Apparently the weights are all standard and adjustment is done by changing the springs. The maximum advance is set by the shape of the cam.

[types26/36]

There seems to be some sort of plastic collar holding it in place but I'm reluctant to start applying force until I have some idea what I'm doing.

Stuart,
I have what I believe is a 43D so I thought I would have a look at it.
It does have a plastic ferrel in the centre which I managed to get out with a bit of prising with a couple of thin screwdrivers, there is a groove in the top of the shaft that I assume the ferrel clips into as it has slightly raised lip on the inner edge.
Whether you can get the ferrel off without damaging it is another question, I think Lucas probably made it "for life"

[69S4]

Stuart,
I have what I believe is a 43D so I thought I would have a look at it.
It does have a plastic ferrel in the centre which I managed to get out with a bit of prising with a couple of thin screwdrivers, there is a groove in the top of the shaft that I assume the ferrel clips into as it has slightly raised lip on the inner edge.
Whether you can get the ferrel off without damaging it is another question, I think Lucas probably made it "for life"

That's what I was worried about, that the plastic ferrule was a one shot item. As I don't have any spare ferrule and I'd rather have a working distributor with the wrong advance curve than one where I've "corrected" the curve but can't put it back together again, it may be better to leave well alone - at least until I see if I can buy a ferrule or two.

No idea whether such items are available as much of these semi obsolete items have moved out of normal commerce and into the hands of small specialist businesses with their own ideas on customer service. One well known distributor rebuilder wouldn't sell me weights and springs separately so he probably won't sell me a ferrule either.

Bill - I did take a look at the other end to see if I could remove the pin but it looks as if it's been peened over so the same problem applies - grind it out and I've nothing to replace it with.

[vikebo]

I had mine apart some years ago for service and lubrication. I removed the gear in the other end by knocking out the pin, but do not remember if I had to disassemble from both ends. Should be possible to find a suitable spring (dowel) pin to fit the hole if the original pin is unusable after the operation? Or maybe measure it and find one before you try?

Eivind

[Galwaylotus]

One thing I can't get my head around is that in the factory Workshop Manual Lotus has the same static timing for both 40953 and 41189 distributors while the former has 24? centrifugal advance and the latter 14?. I would have thought total advance would be the same for a given carburettor setup.

[VDB 50K]

Hi Stuart..contact Martin at distributordoctor.com....he has helped me in the past and is easy to deal with,has plentiful spares available.
regarding the advance degrees....everything is relevant to TDC and the advancement is mechanical.this is set by the weights and spring tension for each distributor designed for each engine type.the lotus manual shows different static timings depending on piston type.the most common static timing is 10 degrees BTDC,but i have seen some set at 7 degrees. obviously the advancement is set at 14 degrees max(set at 2,500 rpm),therefore the total advance is 10+14 =24.
it's best to use a professional timing gun for the accuracy,i use the Snapon,which is perfect.With this piece of kit u can experiment to within 1-2 degrees either side...cheers for now Bill (uk)

[69S4]

A quick thanks to everyone who replied - I've been meaning to do an update for a little while and catching Bill's post has spurred me to start typing. In no particular order - Distributor Doctor's website would suggest they've got everything I need but when I spoke to Martin by email a while back our conversation kind of ground to a halt with me not sure what to do next. Maybe I should pick it up again. Following types 26/36's post and pictures I took my life in my hands and managed to prise off the plastic ferrule without damaging it (much). After that removing the advance mechanism was straightforward and it was all apart in a few minutes.

The pdf ref that BillWill gave me suggested that it was "normal" practice to adjust the total advance with a grinder, so, on the principle of nothing ventured etc, I carefully Dremmeled the total advance to 11 degrees from 7. That should give 22 degrees engine advance + 9 static = 31 total. The graphs in the twin cam engine book suggests that my Stromberg engine should have 33 degrees total (24 from the advance mechanism +9 static) but I'll see how it runs with 31 first. It's easier to remove another 0.6mm than to have to weld some metal back in if I've taken it too far. It all went back together again easily, with the ferrule clipping in ok and is now back in the car. Unfortunately the engine is in bits for other reasons and won't be running for another couple of weeks so I can't check it yet.

I've not changed the springs and have no idea what the curve characteristics are but the published Stromberg curve chucks in a lot of advance quickly so based on what I can infer from the way the springs fit on the posts and their relative strengths it's unlikely to be as aggressive as that. At the moment with both the total advance and the curve characteristics I'd rather err on the safe side as modern fuel isn't the same as the stuff coming out of the pumps when the published curves were produced. My timing gun was pro-spec when I bought it about 30yrs ago although I suspect things have probably moved on since then but it still works ok and I can probably get a rough idea of the curve characteristics if I spend a bit of time staring at the marks. The limitation isn't the technology but my neighbours tolerance