TR2/3/3A rebuilding bomb nose starter

[sp53]

I am rebuilding my back up bomb nose starter and I was wondering about suggestion for cleaning the inside of the case. I would normally pull the field coils and soak and clean the case, but the last rebuilder tacked the screws that hold them in place with a strong weld. Reading the old books they mention cleaning most stuff with a petrol rag. My concern is there is some brush dust from a broken brush everywhere. Maybe some air at low pressure?

 

[TR3driver]

As long as the field wrappings are in good shape, I would think some moderate air would not hurt. But it's not exactly a clean room environment in there, I wouldn't worry about getting every last particle out. A light layer of carbon dust is more or less normal operating condition.

 

[sp53]

Thanks Randall I kinda had that thought about the inside. I figured everyone I looked into has a lot of dust and dirt. This one came with the project and actually looks good other than rust on the outside of the case. I was surprised when I open the case that the cloth on field windings looked new and the rubber sleeve was tight and clean, but again one of those springs on the brushes had broken and made a mess.

Do you have an idea of what the end float should be on a starter? I have looked at many books and cannot find an answer.

 

[CJD]

In my “Guru Exam” my starter was working just fine with 1/2” of shaft float! So I don’t think it is overly critical. It is set by the commutator washer in the rear and the “C” clip in the nose piece.

 

[TR3driver]

The Lucas Technical Correspondence course says end float should "normally" be .010", and to add shims if it exceeds .015".

For the early TR3 starter (which they call "outboard drive" even though that seems backwards to me), the shims should be added at both ends. For the later type, they say to only shim the drive end.

 

[sp53]

I must say .010 sounds like the right number for the end float of starter and the one that is in there now makes a disengaging sound and the ring gear is new, and I do not want to damage it. BUT the end float on the one that came with the parts car is more like 3/8 of an inch, and it looks new inside; it was rebuild but by who? The washer on the end of the armature “I guess for end float” is steel; the steel shims sits below the copper armature, so I guess it should not matter and I have some washers just like it in different thicknesses and perhaps with one them that is about.020 that will pull things tighter and the 3/8s is kinda of the whole deal moving because the starter gear slides out so much on the end with that circlip and retainer set up.

In the past, I would make things like that out of leather because I felt they would last and help with the impact, but I am not sure what to do with this rebuild.

I guess put a shim on the end shaft and see how much the square drive sticks out the end and adjust accordingly.

 

[TR3driver]

At 3/8", there is something wrong or broken. That's not just a matter of needing a shim or two. Most likely (IMO), the little retaining ring ('B' in the diagram below) has popped out of it's groove. Could be other things of course.

The important part is the clearance between the pinion and ring gear, with the starter at rest. See
https://drive.google.com/open?id=0B2H2NJt34OffV290bkxKZzdDUlE
for more info

 

[TR3driver]

"Rebuilt" is not the same as "right". There are "rebuilders" out there who will just clean it up, slap on a coat of paint, and ship it. Looks nice, but they put little or no effort into actually replacing wear components, making sure it's assembled properly, meets specifications and so on.

I once bought a "rebuilt" starter that didn't seem to turn freely. When I took it apart, I discovered the end cap was full of sand! (blast media apparently)

Then there was the "rebuilt" "Stag" differential, that turned out to not even be from a Stag! I found this inside:

 

[sp53]

All the pieces are there and I reassembled it and the end play at the square nut going in and out is about 1/16 to maybe 1/8. They just seem like a lot tolerance because they are so heavy. I read the article on starters in your correspondence course, and I am going to take back apart and put something in the back and I will try something in the front in front by the circlip; it just does not seem like a good place because of the engagement. I guess I can use metal like what is in there in the back? Fiber sounds correct. What do you think?

 

[TR3driver]

I'd go with steel. That armature bangs back and forth pretty good, especially if the play is a bit large.