Ambo Generator Brushes

[luthier]

It's a Magneti Marelli Generator and I'm just going through it with new bearings and a clean, paint and polish.
The brushes are pretty low. I can't see them for sale anywhere. Not at Harpers MG cycle or Guzzino.
Greg Bender says I may have to find some generic ones to grind down.
  I will if need be but just thought I'd ask if anyone has a source of the proper ones?

[John A]

I got my last set from Eishes, been awhile but try them

[rodekyll]

I stopped looking for the oem brushes years ago.  Now I grind/file down larger ones from whatever I have lying around.  It takes less time than getting on the internet.

[Kiwi_Roy]

Your local Auto Electrician may have a selection.

[John A]

I have a can of brushes, mostly new aviation that did not have documentation of manufacturer. I generally root around in there and remark to myself "these are some nice brushes, especially the ones from turbines, too bad the lead is wrong or too massive" sometimes I score but often its quicker to look on the internet if I know I'm going to go into one and I don't want down time.

[Antietam Classic Cycle]

I had my local auto electric shop rebuild a Marelli generator for me once and IIRC, the tech told me he used brushes for a Lucas generator.

[luthier]

Thanks for all your replies.
I'll have a look at some lucas brushes.
Cheers.

[luthier]

I need some advice again folks. I don't think the way my generator sits is correct. It sits up away from the front support where the locator pin goes. Today I made a locator pin as it was missing, but when I tried it out I realized it needed to be twice as long to work.
But from the wear on the gen it seems there once was close contact with the crankcase while now there's a gap. I think someone may have beefed up the base of the bracket making it sit up about 4mm.
Here are some pics.
First here's the locator pin I made today clearly showing where it once sat from the wear on the generator case.


Here it is rotated and the pin hardly engages into the pin hole because of that gap.


Here's the front view clearly showing the gap


OK, so is the gap correct or not please? Or will it pull down once the clamp is bolted down? Doesn't look like it.
I have fitted studs with nyloc nuts to mount the gen bracket and also made a bracket behind to bolt onto the nearest distriibutor bolt so it is going to be stable but if it's too high it's going to need to mods.

[luthier]

I got my last set from Eishes, been awhile but try them

Thanks John. Do you have a link for them please? I can't turn them up on Google.

[luthier]

Damn I hadn't seen this on Greg's site.


Quote:
Generator locating pin

Required. There is a locating pin at the front of the generator that fits into a corresponding hole in the engine block. Make certain that the locating pin is well secured into the body of the generator. The use of medium strength thread locking compound is a good idea. Also, ensure that when the generator is mounted in the bracket, that the body of the generator comes into contact with the curve in the engine block. This curve serves to support the front of the bracket and there should be firm contact between the bottom of the generator and top of the engine block.


Definitely looked that way. O well another mod coming up.

[twhitaker]

Eish is old school and likely still has a rotary dial phone. There is currently a thread on this board going on them called 'Eish Status'. They are located in eastern Ohio and their number is 330-738-3944

[John A]

http://www.scramblercycle.com/  sells an alternator conversion kit. Usually when the gen mount is cracked the easiest way to fix it is to weld a piece on the bottom. This of course is wrong and you loose the pin and need a longer belt and the cover won't fit. Try Eish Enterprises, Salinville, Ohio. I would find the link but it's too troublesome on this apple pile of excrement, they may have a mount also.

[Texas Turnip]

An old school gen, starter, alt shop should be able to fix you up with the brushes.
I stopped messing with generators decades ago and went with a alternator.

Why is your location top secret?

Tex,
Rural Lindale

[twhitaker]

Luthier hails from Oz.

[luthier]

http://www.scramblercycle.com/  sells an alternator conversion kit. Usually when the gen mount is cracked the easiest way to fix it is to weld a piece on the bottom. This of course is wrong and you loose the pin and need a longer belt and the cover won't fit. Try Eish Enterprises, Salinville, Ohio. I would find the link but it's too troublesome on this apple pile of excrement, they may have a mount also.

Yes this is what must have happened. Here's the mod I did first:

I used a really heavy duty bit of stainless for the back bracket.
Given the new info about the piece welded on the bottom I now plan to slice the arms vertically from the base and lower them the required amount and reweld. I'll add some gussetts for good measure once everything is sitting where it should.

Thanks Twhitaker, sorry Tex, never meant to be secretive .
Here's my website for your information, gives contact details , address should you wish to visit and a small window into my daily/lifetime activities.

www.kellawayguitars .com

[John A]

The thinking was that if they would have put those two top studs crossways from what thy did, it wouldn't have been so much trouble. Your plan is good, that's what I do when I find one that is plated on the bottom and with your bracket to the distributer hole it should be trouble free.

[Kiwi_Roy]

If you look at your first picture you can see by the wear marks the generator was clearly sitting on the crankcase also sitting on the banjo bolt head, somethings amiss there.
Are you sure it's not sitting on the nylock nuts?

[Antietam Classic Cycle]

My advice: buy a new, heavier-made generator bracket and weld on an extension back to the forward distributor bolt.

In my experience, the old bracket welded up soon cracks again.

You still may need to make a shim for between the generator and engine case.

[Chuck in Indiana]

Yes this is what must have happened. Here's the mod I did first:

I used a really heavy duty bit of stainless for the back bracket.
Given the new info about the piece welded on the bottom I now plan to slice the arms vertically from the base and lower them the required amount and reweld. I'll add some gussetts for good measure once everything is sitting where it should.

Thanks Twhitaker, sorry Tex, never meant to be secretive .
Here's my website for your information, gives contact details , address should you wish to visit and a small window into my daily/lifetime activities.

www.kellawayguitars .com

A&P inspection. (1) Engine lock nuts have to be of the mechanical variety. The nylon will melt with engine heat. (2) There has to be at least 1 thread completely through the elastic nut.
 
Apparently many of you don't know, but Luthier is a multi talented *world class* classical guitar builder. I'm sure he wouldn't blow his own horn so to speak, but his work is as good as there is. 

[Antietam Classic Cycle]

A&P inspection. (1) Engine lock nuts have to be of the mechanical variety. The nylon will melt with engine heat. (2) There has to be at least 1 thread completely through the elastic nut.
 
Apparently many of you don't know, but Luthier is a multi talented *world class* classical guitar builder. I'm sure he wouldn't blow his own horn so to speak, but his work is as good as there is. 

McMaster-Carr says their nylocks are good to 220 degrees F, I'm not sure the engine housing gets that hot?

[John A]

I think the studs may be long enough, the nuts don't appear to be tightened yet. and if you take Charlies (Antietam Cycle) it may change. I didn't know there was a bracket like that, looks to be up to the task.

[Antietam Classic Cycle]

I think the studs may be long enough, the nuts don't appear to be tightened yet. and if you take Charlies (Antietam Cycle) it may change. I didn't know there was a bracket like that, looks to be up to the task.

The bracket itself is available from several sources in the US, I fabricate and weld on the extension back to the distributor bolt myself.

[luthier]

A&P inspection. (1) Engine lock nuts have to be of the mechanical variety. The nylon will melt with engine heat. (2) There has to be at least 1 thread completely through the elastic nut.
 
Apparently many of you don't know, but Luthier is a multi talented *world class* classical guitar builder. I'm sure he wouldn't blow his own horn so to speak, but his work is as good as there is. 

Thanks Chuck, you are correct with the 2nd point and I need to grind a bit from the bottom of that nut if nyloc will take the temp.
I did that stud shorter than the back one. It wasn't intentional but when I cranked the back one down the thread stopped it before nirvana.
I don't have the taps and dies to make all this stuff failsafe. Anyway, no excuses, I'll get that down to the right level and will need to once the level of everything is lowered.
Still into my original plan to lower the bracket by cutting and shutting. Seems logical to me. I'll post pics of my amazingly bad welding.

[Chuck in Indiana]

McMaster-Carr says their nylocks are good to 220 degrees F, I'm not sure the engine housing gets that hot?

Trust me,Charlie.. *maybe* not on a motorcycle application, but they will definitely melt in an airplane engine compartment. At any rate, I don't use them on an engine. 

[luthier]

After realizing that the base had been plated I cut the plate off and welded some of my own.


The plate on the left side is low enough for the oil line  to go over. The plate on the right is set up a bit so there's a gap for water to run out.

The assembly now sits down and allows the gen to make good contact with the crankcase at the front.
I actually ground the front arm a bit because the gen still had a slight wobble when sitting there.
Now with the two clamps in place I can't get a feeler guage between gen and casing up front.
I had to bend the rear bracket a bit but now it all sits square. Hope this will be strong enough now.

[luthier]

My advice: buy a new, heavier-made generator bracket and weld on an extension back to the forward distributor bolt.

In my experience, the old bracket welded up soon cracks again.

I'll see how it goes Charlie but the thing I don't like about your design is you can't take the dizzy out without taking the whole generator assembly off. Maybe it needs to be like that, I don't know. But I haven't seen anyone reinforce the old bracket the way I've just done. Maybe my design will be stronger.  I guess time will tell.

[luthier]

By the way, back on the original question, our special person in Oz who renovates dizzys and generators and all that kind of thing, by the name of Peter Scott, has confirmed that Lucas E3L brushes will go in a Magneti Marelli Gen with a small amount of sanding to reduce the length.
I imagine sharpening the ends correctly will be the hard part.

[John A]

I imagine sharpening the ends correctly will be the hard part.
[/quote]

Wrap a piece of sandpaper on the commutator to get the right contour, if you can figure the length

[Antietam Classic Cycle]

I'll see how it goes Charlie but the thing I don't like about your design is you can't take the dizzy out without taking the whole generator assembly off. Maybe it needs to be like that, I don't know. But I haven't seen anyone reinforce the old bracket the way I've just done. Maybe my design will be stronger.  I guess time will tell.

Yes, you can easily remove the distributor done this way. The base stays in place, but once one M6 bolt is removed the distributor itself pulls right out. There's rarely any need to remove the base anyway.

[luthier]

That's definitely a lot more rigid than my attempt Charlie.
 And I like the way you line it up. Do you just tack it in situ or fully weld it there?

When mine lets go down the track as it most likely will  I'll go that way for sure.