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Lanchester LA 10 Distributor Information Wanted

Technical issues not related to a DLOC car marque, eg tyres, ethanol, other car makes, etc. and legal, political and insurance
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JT7196
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Joined: Sat Feb 13, 2016 7:22 am

Lanchester LA 10 Distributor Information Wanted

Post by JT7196 »

Hi Chaps, very recently Dave French asked the question on here re the, mechanical advance specifications for his LA10.
This morning, Martin Jay telephone me asking if I was able to supply the relevant details, which unfortunately, I was unable to do.
This got me thinking, ( Thursdays, being my "Thinking Day" of course) , because of the production of motor cars being virtually halted by the 2nd world war, would it be fair to assume, that the Distributor specifications for the Post war LD10 would have been similar to that of the earlier models, assuming development work would have virtually ground to a halt during the war?
I only ask, as you are probably aware, that the "Correct" spec for the earlier models seems to be virtually non existent, and with Martin Jay suggesting that he did indeed have the Spec for the LD 10, whether this Spec could be incorporated into the LA10 Distributors.
What does the " Team" think????

Cheers A'l ;) :P :P :roll: :roll: :roll:

Simon Hyslop

Re: Lanchester LA 10 Distributor Information Wanted

Post by Simon Hyslop »

The LD10 engine has virtually nothing in common with the LA10 engine, the placing of the rear external oil feed pipe to the rocker shaft being about the only slightly similar thing that comes to mind, in dessign if not detail.The LA10 must have been one of the very first designs to have automatic timing advance and things had moved on considerably by the time of the LD10's design. The LD10 distributor also has a vacuum advance mechanism. It is the vacuum advance that makes the most difference to low speed wide throttle openings and also to fuel economy.

I did reply to Dave's question, how practically useful the information was I can't say, but any similarities of the 11 distributor (i.e. 1444cc late engine as I think Dave's car is ) lay with other just pre and postwar makes using the same distributor components.

The earlier 1203cc 10 was using different weights and springs which mean different advance characteristics.

The LA10 distributor comes from the generation before and I can have a look up what weights were used (though not tonight) but the aim, and result, at the time would be to provide some advance (4-6 degreees maybe) as the engine speed increased. It would be a fairly general application in place of the owner moving the advance and retard lever on the wheel "a bit" when going up hills and the general use of the self starter had greatly reduced the need to retard the ignition when starting by hand.

By the middle 30s things had moved on quite rapidly and a better understanding of an ignition curve and specific applications starts to appear. Others may disagree with this analysis but I think if you look at the Lucas parts lists they bear this out.

Also, when considering what needs to be done to recondition a distributor of the early 30s, I offer a thought. At the time, quite a few cars still had either magnetos (Austin Heavy 12 to 1934) or no automatic advance at all, just a hand lever (Austin 7s to 1933).
How do we visualise someone driving a car like this? Is it like a 30s film where the driver against the moving background shuffles the wheel constantly? No, it's not. You may retard the ignition to start but thereafter the control needs touching very little.
In other words, zero advance and retard is actually ok for much of the time with these long stroke engines. Some advance will help more in a high speed engine but if the engine is just not performing well, I think I'd look elsewhere for a problem and not overthink what the distributor is doing.

More modern high revving designs have different concerns but I think that for the 1932-34 10s their design in this respect was firmly rooted in the time. A small degree of automatic advance provided a better running engine, no doubt, but chiefly it eliminated a control that some owners would never actually use.

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