Cleaning crankcases?

[sprint]

Engine is out while doing a restoration of the bike. The barrel, head and cam cover have been vapor blasted and whilst a more mat finish rather that the original more 'shinny' finish it still looks a hell of a lot better than the grime it has accumulated.

I am not splitting the crank cases as the bottom end is fine. However, whilst I have gone over it with a small wire brush on a Dremel to remove the oxide and crud it still look grimy and and dirty compared to the cleaned top end.

Any suggestions as to how the crank cases can be cleaned (a bit) without splitting them and having them put through a vapor, or similar, cleaning process?

Have tried a bit of 'Rub and Buff' on some discrete areas but it it looks too artificial and more like a mat painted finish.

[Jay1969]

Soda blasting...


~Jay.

[freddyz1r]

DON'T SODA BLAST.
from my previous, very limited experience. It gets absolutely everywhere.Can you be certain that it hasn't entered the bottom end you'll end up stripping the crank, gearbox out etc If you can find a definate way of 'masking' off, then please let me know, as I am having a similar dilemma. I have almost come to the conclusion that stripping the engine in its entirety, will probably be the only way.
cheerz freddy

[Jay1969]

Good point Freddy, how about cutting a sheet of thin ally using a base gasket
as a template, with holes for the conrods, mask the head and barrels completely,
bolt all down, cam cover on, leaving all the side covers on too of course.
Or shall I just get me coat ?

~Jay.

[freddyz1r]

Got possibilities
Do a 'fake' re-build of the motor. Could be a plan
now get your coat and come and re-build mine
cheerz freddy

[sprint]

Thanks for the replies.

I had similar concerns about the soda blasting. As indicated, I already have the barrels and head off and would like find a way to clean the crank cases a bit better before re-building.

Definitely don't want to be splitting the case just to clean them.

Have any other members found a way to clean the cases? Are their any chemical cleaners that can be used as using a wire brush on a Dremel does clean up the top surface of the alloy cant get to the lower surfaces ingrained surfaces.

[freddyz1r]

Sprint, one of the things I'm experimenting with is 'caustic soda and wallpaper paste' ( you can brush it on, into all the little nucks and crannies and then rinse of.)
Early days yet but has serious possibilities. On the scrap I've tested it on it removes everything, grease, grime, oil,paint the lot. Just takes several attempts( I'm a bit weary of the 'caustic soda' as it seams quite potent).
Cheerz freddy

[sprint]

Hi Freddy.

Seems like a possible solution, though you do need to be cautious with caustic soda.

My cases are free from oxide, grease etc. The aluminium has an 'orange' peel type surface and it is the lower surfaces that need getting to which is why a chemical solution might work?

Please keep me informed of how you get on.

Andy

[z1bman]

with all the work you have done why are you holding back with the crank cases when the engine is half striped anyway. its only a couple of hours extra work to strip & rebuild & getting them professionally cleaned will make all the difference to the motor

[chrisu]

with all the work you have done why are you holding back with the crank cases when the engine is half striped anyway. its only a couple of hours extra work to strip & rebuild & getting them professionally cleaned will make all the difference to the motor

^ This......................

[sprint]

For those of you who have done it many times it may be fairly straight forward, but I have not and I don't really want to go that far just to clean the cases when everthing else is fine.

Was hoping that this was something that a few members had come across in the past and that there may have been a process that can do a reasonable job without having to split the cases?

[ruffle]

Caustic Soda (Lye for our colonial cousins) eats aluminium very very quickly.

I know this as I've just been using some to dissolve chunks of welded aluminium off a milling cutter that got stuck there when some idiot told it to plunge 10mm instead of 1mm

I would not consider using Caustic Soda to clean aluminium.

Soda blasting is useful for things like carbs as the soda (sodium barcarbonate as used in cooking) dissolves easily in water so you can simply wash out the blasting media - something you can't always do with beads or other media.

[chrisu]

For those of you who have done it many times it may be fairly straight forward, but I have not and I don't really want to go that far just to clean the cases when everthing else is fine.

Was hoping that this was something that a few members had come across in the past and that there may have been a process that can do a reasonable job without having to split the cases?

you could try diluted brick cleaner but I'd suggest you try it on something else first to practice. You'd need to be careful on anything polished obviously.....

[z1bman]

http://www.ebay.co.uk/itm/heavy-duty-Al ... 1e9a6505ae

[Z903]

You can do them by hand.
These were actually painted Black...stripper, scourers and hand polishing.
Probably wouldn't bother doing it again, but it's certainly achievable.