How to clean engine cases and guts

One important thing I learned when researching "how to's" with scooter restoration is people sometimes accidently mislead you and the affect on their instructions turns out to be negative; therefore I speak with multiple people before doing anything at all and I look for patterns. If 3 of 5 people tell me the same thing, I tend to trust them most and then take action.

From my previous restoration, I have collected a few mentors and I always ask them what their opinions are . . . more times than not they all say the same thing.

I make sure to always post everything that I learned so you guys know the options that are out there or can comment on which method to avoid and which you prefer and why.

I want to know the best way to clean the engine cases and guts of the engine to make it look as close to stock as possible and to be as gentle as possible on the cases. This is the question I sent them: "I wanted to ask you guys if using simple regular gasoline and a copper bristle brush would be the best way to clean the engine cases and the internals? Suggestions for cheap and SAFE way to do this?" Here is what I have learned so far:

Christopher Markley says:
"Get some reduced odor paint thinner. Works nicely. Some swear by orange cleaner or simple green. I've found they can be tough on aluminum. Maybe it's just the brands I've used. You don't want to pit seal surfaces. Try the paint thinner -- low odor variety (low odor is a relative, marketing term!!)."

Stu Werner says:
"I use kerosene and a five gallon bucket a third full. Not gas. I reuse it when it gets real dirty by straining it through a t-shirt. If you have the cases stripped you can get the case, case side glass bead blasted. They clean up real nice that way."

Tom G. says:
"But frankly, the solvent (gas is fine -- I keep a container of used brake cleaner hanging around for this purpose also) is going
to do most of the work, so paintbrushes and toothbrushes are good enough for this."

I posted this question on LCUSA as well and Mike Analt responded. He has given me some great information so far. This is what he recommended.

"I find the best way to clean cases is to have them soda blasted then follow them up with some white vinegar. The wash with hot water. You end up a very factory look about them.

There is a guy local to me that does all my blasting needs (baking soda or glass). I have him blast the cases, cylinders, frames, body work etc. he's really good. Soda for sensitive parts (all alloy) or just paint stripping. Glass for rusty cylinders and frames. For internal parts I use carb cleaner, compressed air and paper towels. I just posted a link to a glass blaster mounted to a pressure washer. When I get through the holidays I'll look in to picking one up. It should give the parts the freshly vapor blasted look."

For a deeper understanding . . . sodablasting is a process where sodium bicarbonate is applied against a surface using compressed air. It was first used to restore the Statue of Liberty. Sodablasting is a non-destructive method for many applications in cleaning, paint stripping, automotive restoration, industrial equipment maintenance, rust removal, graffiti removal, molecular steel passivation against rust, oil removal by saponification and translocation, masonry cleaning and restoration, soot remediation, boat hull cleaning, food processing facilities and equipment.

Another option from LCUSA member Brianxyl:
"After several engine rebuild projects I've kind of got a system now. Groaty engine cases and internals clean up great with purple or orange degreaser. Big positive for using this over gasoline or other solvents is that it doesn't stink, isn't carcinogenic or flammable, and you can use it indoors. Way cheaper than taking parts to any outside blasting service. Yes, it does tend to darken aluminum (only the outsides of cases for some reason) but my next step is to use a soft wire wheel on the cases to make them look just-cast fresh. I made a craptastic parts dryer by cutting two holes in a cardboard box and shoving a hairdryer in one of them. It'll dry the water out of cranks etc before anything can flash rust. Great for when painting small parts as well."

More to follow . . . pictures and my final decision on how to tackle this part of the job.