Talk Morgan Forums Morgan Sports Cars Maintenance & Servicing Rebuilding Lucas 25D

Hello all,

I just rebuilt my distributor, a Lucas 25D, and it's working great. My car was very original when I bought it and on starting it really seemed to struggle to find spark. I dove in headfirst and started upgrading the electricals. I think the only thing I really needed was new points, but I decided to throw in a pertronix I ignition and when I opened up the distributor it looked nasty inside.

I installed the new ignition into the filthy distributor, just to make sure it worked (which it did), and then decided to clean the whole thing up. I found some good guidance on a website (http://simonlacey.com/pages_new/content/distributor%20rebuild.htm).

The only thing I really struggled with was getting the drive dog's pin out. I made a wooden jig to clamp the shaft in a vice without cracking it, but still it wouldn't budge (despite penetrating oil; maybe next time I try a 50-50 ATF/Acetone blend which some say is better). So taking a page from King Lear ('Striving to better, oft we mar what's well.") I decided to leave it and clean up every part I could with the shaft still in situ. Suboptimal yes, but way better than nothing. And I still managed to get the bottom cleaned out by wedging a bit of steel wool under the plate upon which sit the centrifugal weights, and rotating the shaft. Much carb cleaner as well. Then lubricated and reassembled.

At some point I do want to get that pin out, as the drive dog's washer probably wears out and needs replacing.

On the somewhat humorous side (or frustrating, depending how you look at it), I decided to give the very rusty cap clips a quick spa treatment on the wire brush side of my bench grinder- worked fine for one, but the 2nd caught on the brush and was instantly rocketed somewhere in my shop, and promptly disappeared within the jungle. My kids will probably find it when the are clearing out the house once I've passed on, so I ordered a replacement. Maybe it'll turn up but am not holding my breath.

Took much care (and photos) to ensure that I put it back together exactly as I had taken it apart, to avoid having my timing off 180 degrees.

Starts up strong. Now to see if I can find that timing mark on the balancer and do some dynamic timing. While much is written that a TR4A engine is to be statically timed, not as much is written on the right way to time a 50 year old TR4A engine. I got advice on that from my friends at Morgan Spares, and will give it a shot.

Log on to the TR register and ask there.

http://www.tr-register.co.uk/forums/index.php?/forum/5-tr44a-forum/

I have a box of 25D Lucas Dizzy's. I was tempted to do the same as You. But found for $140 I could buy a new one from "British Parts NW". This I did because I am lazy. But not sure I got a good deal. The vernier timing is notchy. The marks that should be on the vernier are not there. It seems to work OK. I static timed it. Will have a better mechanic time it and set the carbs.

You can do no better than take advice from Morgan Spares. Robert Couch (Founder of Morgan Spares) tuned my TR engined Morgan each year until He died. My Morgan was always in the best of form.

Button
Seattle

On my TR6 I timed it dynamically as a starter at the same degree as static. At idle speeds the advance won't have kicked in so its a good place to start. There will be a 'sweet spot' depending on engine state and fuels used etc..

On old engines it's kinder to err on the retarded side rather than advanced but only a tad.

I too have a number of 'missing' items that have been sent to various parts of my garage by the wire wheel/grinder, some day I'll have enough to make something useful.

I just went through a round of trouble shooting ignition problems with a Pertronix ignition. I bought the third generation and it didn't work out well for me. Pertronix is sending me a second generation unit.

What I did learn though was that the easiest way to set timing with the solid state ignition is with an advance timing light. At 500rpm, before the centrifugal advance comes on, point the timing light at your marker, and dial in the advance you want. Dead simple.

Did you change out spark plug wires for ones with better EMI blockage? May help with the more advanced ignitor models. I went with a ignitor I, which is reportedly less of an issue.

Isn't 500 RPM below your idle setting?

I set the mixture the old fashioned way for a SU. Procedure is in my Handbook. However; I will drive the steep hill behind my home and listen for the "PING". Advance dizzy until I hear the "PING" then back off a bit until I don't hear the "PING". This should work until "Father's Day" when I will be in Victoria, BC. Jim Walters will tune the +4 at that time. It was Jim that tuned My +4 just prior to my Key West and Europe trip.

Button
Seattle

I changed out everything. I was convinced I had an ignition problem (which I did), but it turned out to be an issue with my new parts. I'm back on points and condenser... tried and true.

The car should idle out around 500-600. My final idle is usually set betweem 750-900. The goal is to keep the centrifugal advance from affecting your timing adjustment, so the lower you can get the car to idle out while you're setting the timing the better.

Interesting. My plan is to dynamically time to around 32 BTDC at 3000 rpm, and then measure the advance at idle. I'll bet the car is just as happy at 8-10 BTDC at idle as it is at the factory recommended 4.

I also think I need to adjust the idle a bit and see where it sounds happy.

Timing mark??? Is it in Braille? There is talk of a hole but I can't seem to see one.