14 replies to this topic

[ac427]

I bought a couple of rod change gearboxes a while back and have started to strip them. I noticed some quite deep scratches on the gearbox casing engine mating faces.

 

Obviously i would like to minimise the chance of oil leaking. Is it safe to remove remove material from the face and would it affect the mesh of the drop gears?

 

 

I'll post some photos when i get back.

 

 

[sonscar]

Are you going to mill or flycut the entire perimeter?I guess it depends on how much you intend or have to remove,Steve..

[Shooter63]

I think if you milled a lot off you will run into problems with the idler gear meshing with the primary gear, a decent amount of measuring will be needed.

Shooter

[nicklouse]

Pictures needed.

[Spider]

Usually, if the scratches are below the surface, with the width of the flange faces, you'll be fine. Anything that raised or goes from one side to the other though is looking for leaks.

[Pigeonto]

No you can't do that. You'd have to move the needle bearings, bolt centres, dowel in the cover by the same amount.
There's some brilliant epoxy products, JB Weld for instance. Once cured, scraping or
filing back flat.

Edited by Pigeonto, 12 June 2022 - 07:49 AM.

[nicklouse]

No you can't do that. You'd have to move the needle bearings, bolt centres, dowel in the cover by the same amount.
There's some brilliant epoxy products, JB Weld for instance. Once cured, scraping or
filing back flat.

Yes you can. It is what you do to set the lash on your drop gears. It also is done when you line bore your main bearings for new caps.

[ac427]

Here are the mating face scratches

 

 

I'm not sure why the flash produced a blue hue to the lower innards of the gearbox casing?

Edited by ac427, 13 June 2022 - 12:58 PM.

[whistler]

MED do a 5/16" sump gasket conversion kit using copper gaskets. I assume that these are available at different thicknesses, similar to cometic head gaskets. Would this solve the problem of over skimming the aluminium faces and the consequential problem with drop gear/idler gear alignment?

[sonscar]

I would use some wellseal or stag on that and bolt it up with no hesitation,Steve..

[nicklouse]

Don’t see anything to be worried about there.

[mk1leg]

use emery cloth on a 2x2x10 inch sq steel tube and sand it back I'ev done this many times on boxes

[mini13]

I dont see anything that drastic there, my main concern would be any raised bits next to dings, i'd knock those back flush, and just use a sealer on the gaskets, welseal or Loctite 574 are my favorites

[Gaz66]

Don’t see anything to be worried about there.

Likewise...ive fitted worse and not had leaks.

[Pigeonto]

That's interesting Nicklouse, I've never tried to set the drop gears lash by machining the gearbox flanges. What do you do to bring  the 2 bearings in the drop gears cover back into alignment. ?

 

""Yes you can. It is what you do to set the lash on your drop gears. It also is done when you line bore your main bearings for new caps.""

 

Edited by Pigeonto, 15 June 2022 - 01:04 PM.