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Lucas 45D internal parts


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Can anyone tell me the factory spec of the internals for the 45D on a 1500 engine?

More specifically a YC engine code (according to this it's for a rear drive dolomite http://www.triumphspitfire.com/enginenumbers.html).  I've looked in the distributor and it has a cam with 8 stamped on it, which I assume is 8°.  6 of which appear to be controlled by the primary spring.  The advance feels a bit sloppy too so I'm not certain it's doing what it should and before I put too much effort into trying to resolve the issues I'd like to know if it's the right thing.

I'm putting off doing nodiz/megajolt/123 for the time being, mainly as the limited car budget should probably be spent on getting it driving first!

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Thank you John,

That's lead me down a search path where I've found out some better information (funny how a particular key work or piece of information can trigger that).

I can't quite match up that the curves I can see imply that those distributors run over 12 degrees centrifugal advance, which is why I'm confused about the 8 degree cam mine has which at least is safe, if not fast.  The distributor is stamped 41449 which appears to be the correct one for the engine, so I'll assume the cam is right and just work on getting it running ok before taking the programmable ignition leap.  I've attached a photo of the distributor below the base plate if that's of interest to anyone.

I'm struggling with using a timing strobe as the engine isn't running well enough to use one reliably so the only time I can use the strobe appears to be at max advance.  I think there's a vacuum leak in the inlet somewhere, so I think it's off with the inlet side, re check all the gaskets then re-assemble.

distributor.png

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I vaguely remember looking into this when I had 1500s in my Herald and was constantly trying to make it faster.

IIRC the curve changed part way through production and was reduced significantly, so I think the one you have is a late one. I’ve seen various explanations for this including emissions, reduction of crank rumble (improved refinement) and trying to stop the blowing up.

With 8 degrees distributor advance, the total will come out at

8x2=16 + 10 (static advance)= 26

Most 2v ohvs need 30 - 32 to give best results so I would consider a 12deg unit a better bet.

Of course, that 8 (or 12) will come in in stages dependent on weight shape and springs.

You might find this interesting, especially the timing from the top down (I’d use 4K rather than 5k, it should be all in by then)

 

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Poor wording, the better information was managing to find the info that this specific distributor was the correct one for a 1500 spitfire and/or midget, so should be reasonable for my engine.  Turns out I needed to search for only part of the code stamped on the distributor to actually get some results.  This showed various timing curves associated with them, and several places selling them, but not one tells you what max timing is inside!

Nick, that's very helpful too.  I think I can get it revving up to 5k so doing timing from the top sounds sensible.  I will probably need an assistant due to a lack of hands, so will have to catch the wife on a day when petrol and old car smells aren't a problem...

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Hello Egret,

The number stamped on the side indeed does identify the distributor and should have one advance curve;  you mention several? The maximum advance is the top flat line and can be read from the graph scale.

 

Alec

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Thank you all.

Actually managed to get it idling properly last night.  The most recent stupidity was to not check the needles in the carburettors.  Pulled them last night on a hunch and discovered they were green.  Corrosion means the needle profiles were pretty much random hence the difficulty getting it steady.  Advance was set to 32ish at high rpm, but all the mechanical advance seems to come in really early still, so I'm pretty sure all the slop in the distributor is going to stop the car running really sweetly.  It still runs and I now need to start saving and looking for nodiz/megajolt/speeduino/123tune etc.  I think the idea will be try to find one of these second hand, and if that fails I'm leaning towards nodiz being best - probably worth a dedicated post.

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