Engine....Cleaning the Castings

[Mike Sal]

Those of you with beautiful restorations......what did you use to clean the crank case & cylinder jug?  Mine has that dull splotchy look that aluminum gets as it ages in the weather (but it doesn't have any white corrosion).  In looking at Rick's restoration of his crank case, it looks like new.  I don't see evidence of shot blasting or wire wheel abrasion (both of which I'd rather avoid).
thanks,
Mike Sal

[Ricks]

My engine case was new. I cast it in my home foundry.  LOL!! 

What I did is remove the old bearings, then I lightly glass beaded the case.  Then I used some 600 wet sandpaper and smoothed it out a little.  After that, some mag wheel polish to give it a little shine.  When I first started on it there was a little of that white powdery corrosion on the bottom of the case.

Tip:  Do NOT pound the bearings in and out of the case, as you have a good chance of cracking it.  Heat the case in the oven to about 275 degrees and the bearings will come out with little effort.  To reinstall the bearings do the same, and I also put the bearings in the freezer while heating up the case, just for good measure.

[kartjockey]

That's pretty much the way I did my case. I had to do some extensive machine work inside to make it right. I had to sleeve the the hole that holds the bearing races because the engine had digested to much dirt and wore the block where the rotary valve runs in. I have a known running clearance now. (.002'). Guys would take vacuum pulls to see how well there crankcase(base) pressure would work for them thus predicting how well their engine was going to run. Poor base pressure means poor charging of the cylinder. I put the sleeve in exactly as Rick suggests in removing and installing the bearings. And still I remember being scared to death. I mean, where's a guy go to buy a numbers correct block!!

[Ricks]

Hey Tom, any block is hard to find these days!  And , if you change engines, there becomes that hassle with the local DMV when the number no longer matches the registration.

Tom, maybe you could machine us some billet aluminum blocks!

Rick

[mywaymfg]

I've been trying several polished on this engine with out much success , after sanding what is the best polish?

[bill marcum]

I am not a expert but I was thinking that after you sand a part down then you should use a buffing wheel with some buffing compound that is for that kind of metal. Bill Marcum

[mywaymfg]

Wonder, what is best for aluminum . I have tried for years to polish the aluminum parts on my 76 sportster same problem I can make it better but never like new