Tuesday, 7 April 2026

Model A - Lucas E3 dynamo

So what's next? With the kickstart done and the gearbox back together, my plan is to reassemble the primary drive to get the bits off the bench, and move on to the front forks - a big unknown. They didn't have bushes in 1930, so we are looking at a machining job at home or away. To get there though, I have rebuilt the clutch and next is the primary chain and covers, which just need paint. I'd like to reassemble the dynamo and it's drive, but it's toast. I could either:
  1. leave the dynamo in a box for a few months and get on with other things
  2. reassemble it mechanically (the body needs replating)
  3. Fully restore the dynamo
I've got no zinc plating chemicals, and I have a long list of FH bits that need plating which i don't really want to get into right now (and as of this afternoon, my son has taken the Huntmaster and left me with the Square Four which won't idle...); I don't want to leave the dynamo bits in a box for months, so we will go for option 2. I've also seen at least one picture of an E3 dynamo with a painted body - and I've seen another picture of a 1929 bike which made me realise that you can't really see the body when it's mounted on the bike!

Here's a photographic survey of the dynamo:


In the picture above you can clearly see the damage done to the armature - it's thoroughly bent and unrepairable. Notice that this early E3 has the magneto type open ball bearings and the taper fit for the driving sprocket along with the male thread for the retaining nut. Characteristically, the armature is 157 mm long. Putting all this together enables us to purchase a new armature for this 36 watt dynamo.

I've ordered this repair kit from Rex's Speed Shop which will include the proper bearings:


As I may have mentioned, this is just going to be a photographic survey for future use. Here are some views of the dynamo body and the commutator end casting:





Close up, we can see that the other dynamo and casting has been a victim to the side swipe that this bike has suffered - there is a crack in this end as well. It looks repairable though:




 

No comments:

Post a Comment