Questions re: aluminum corrosion and coating

[Jim Garry]

Hi everyone. Today I finished cleaning a used bellhousing that is new to me. Cleaned it in a parts sink. Spent a lot of time on it. There are two problems I hope you guys can comment on.

1. The aluminum is corroded in places. Perhaps galvanic corrosion. From the photos, can you say if it's serious? It would take some time but it seems it could be scraped away. If it remains, could it come off in the hot engine oil that is stored there? The last two photos posted below show before and after some scraping.

2. There is a black coating on the outside and inside of the bellhousing. I have no idea what it is. Using the parts cleaner on it turned some of it gooey. It could then be washed off. But some of it wasn't affected by the wash. It's still there. I can scrape that off too but there's a lot of it and scraping leaves a lot of debris behind. And regardless, all those nooks and crannies will prevent access in places.

Question: Are these issues something that must be addressed before the bellhousing can be used? Or am I giving this more concern than it deserves?

Thanks for your comments.

[steve zemke]

Dip and strip, media blast and sealer? Clean and Anodize?

[R. Pare]

Those bellhousings were made both in aluminium and mag, but mostly mag. Something like a 10-11 pound difference between the 2. Steve might remember what the weight were. You will need to determine which material it is before treating it.

The black stuff could be Kefos or something like that. i was never impressed with their stuff.

[Jim Garry]

Thanks RP

[Jim Garry]

You will need to determine which material it is before treating it.

Just dropped it off for bead blast and then hot wash. S'ok? They'll get to it Monday.

[S Lathrop]

I would suggest that you use a good quality 2 part epoxy primer and just paint the exterior of the bell housing. Primer only, no top coat. Just priming is a way to refinish wheels. It has the advantage that it can be touched up easily.

But before you do that prep the aluminum for the paint. Here is a video on what to do: https://www.youtube.com/watch?v=SHePtG9LtIU

[Jim Garry]

Will do!

[Rick Iverson]

WRD has a vendor that applies black Teflon to aluminum gearboxes. Looks real sharp, very reasonable, and I understand quite durable. Might work.

[tlracer]

In some of the pictures it looks like the bellhousing has possibly been painted with the black coating. Mating faces are clear of the stuff and there look like masking lines in some areas.

If it's magnesium then you could have it chromated - I've just had an old magnesium wheel done and the finish is excellent. Prior to the work it had the usual grey, powdery surface but now a uniform dark grey finish.

[Jim Garry]

Thanks everyone. It's alum. Had it lightly bead blasted and then hot wash. It looks pretty good now. Still have some of that black gunk but it's so thin that it isn't flaking off anymore.

[Rick Kirchner]

there's an excellent coating for the inside of oiled castings - seals porosity and sheds the oil. Unfortunately the name escapes me. Its a coating we used to use on military electronics - windings and such. I think the brand starts with a K. If nobody else knows of it then I'll search the forgotten recesses of my mind some more.

[Daryl DeArman]

Are you thinking "Carboline"? Phonetically your brain may be recalling a "K" brand.

[Jim Garry]

In the third post, above, Richard mentions Kefos. Is that what you're thinking of?

[R. Pare]

In the third post, above, Richard mentions Kefos. Is that what you're thinking of?

No - absolutely not Kefos.

[DanW]

there's an excellent coating for the inside of oiled castings - seals porosity and sheds the oil. Unfortunately the name escapes me. Its a coating we used to use on military electronics - windings and such. I think the brand starts with a K. If nobody else knows of it then I'll search the forgotten recesses of my mind some more.

Hello Rick,

Do you mean Glyptal?

https://www.hisco.com/glyptal?msclki...ontent=Glyptal

[Rick Kirchner]

Damn - how my brain got K out of G I have no explanation. Yes - Glyptal!