I bought a new 25 year old Webra Speed 20 Marine engine awhile back. It was stuck worse than epoxy when I got it. I slow cooked it in anti-freeze just to be able to knock it loose enough to disassemble it.

After everything was free from the crankcase casting, I de-burred, filed, sanded, brass brushed, scotchbrighted and then finally soft scrubbed with Cameo sink cleaner, scrub rinsed it in fresh water and the aluminum was looking FRESH!

I thought for safety reasons just to be sure everything was out of the aluminum and the nooks and crannies, the only thing I could think of other than hitting it with brake cleaner or anything else that could be caustic, to save the bright finish, I boiled in a teflon coated saucepan of tap water, thinking that should do it.

After ten minutes of a rolling boil, I reached in with my tongs and fished around and pulled out what I thought was disaster to the finish.

Looking at the surface I notice these tiny little blooms of crystals here and there, and the aluminum started to go dark on me.

I assumed because this was a casting, something was still in the aluminum...albeit anti-freeze or cleaning cleanser.

I soft brushed it again with just dish soap to remove all the blooms, rinsed the pan, and boiled it again with fresh water.

Second time around it developed a rich, burnt iron color that seems hard as nails - but there were no more crystal blooms.

Thinking I am safe now of anything trapped in the aluminum, I liked the color better than the bright finish - and I know nothing else could have survived that the engine will ever see except nitro and exhaust tempuratures.

To be double sure I fired up the oven to 450 degrees with the case on a cookie sheet and let it bake for a half hour just to see what would happen to the surface. The only noticable difference was it picked up a gloss, so whatever it is thats on there melted a little I figure, and got a harder surface.

I haven't done anything to it yet as far as brake cleaner or scrubbing...so I dont know how durable the finish is on this, or if it is anything to be concerned about when I go to heat it up again to install the crank and bearings.

Take a look at the pictures and you decide what happened or what should be done.

What do you suppose caused this? The anti-freeze or the sink cleanser?

The first picture is what it looked like as I recieved it. The second pic is what I have right now. Whatever caused it is now on the surface of the aluminum. And it is evenly coated with color, inside and out, cast surface or machined.

The sink cleanser did the deed. It was caustic.

Engine really doesn't look too bad. I'd go ahead and use it.

Jim

My preferred method of cleaning lately has been to soak the parts in a warm solution of dishwashing powder. I've found that if I boil them then there's likely to be some colour change but if I only warm the water to a point where it's just getting uncomfortable to take the parts out with my fingers then they can stay there all day with no colour change. You said you'd rinsed off the sink cleaner before boiling in tap water and that's when you got the colour change so I can only guess there's something in tap water that can affect aluminium when boiled. Our tap water has a fluoride treatment, not to mention all the other minerals and such that's always in tap water.

Yes the water could have had a high PH and boiling made the reaction

House water usually is on the basic side of neutral PH.

Aluminum has to be treated with a very slightly acidic PH water to remain shiney.

I have a Webra speed .61 muffler that is the same color...all I did was boil it to clean it out after I did a little filing in the port opening? I thought it had something to do with the heat, but maybe it's the Ph of the water? Or both???

Edit: It shouldn't be just heat related, because the exhaust gasses get a lot hotter than boiling water, aye?!
Maybe the chlorine in the hot water reacts with the alloy?

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I wonder if the piston/liner fit has been affected?

The build up never added. It looks like anodizing which is a process that does build up a surface, but this seemed to just add color to what was already there.

I knew the liner fit before and it did not affect it. That was one of my first concerns also, and went directly to fitting it when it reached room tempurature.

I would have welcomed another .001", as restoring the case and the liner did remove what should be a soft press fit. It is more of a close loose fit now, but is still full contact with no play once fully seated. I am sure once the motor is run-in and castor starts to build, it will once again be snug.

This restoration to what was a fully hardened and locked grease case has had me worried every step of the way. Repair or replacement parts are non-existant, minus bearings and screws, and the ultimate Dynamix carb of course!

This seemed to be another curve ball added to that, but honestly if the finish holds up and does not leave off in large patches with no remedy to clean the rest of the nooks and crannies, I think it is a very good color to have!

If the chlorine in the water did actually do the coloring, please remind me never to brush my teeth in boiling water[sm=surprised.gif]

I think it looks pretty cool![8D] I like it...
Probably an oxide coating? My muffler didn't come out quite so even looking though? It looks kinda blotchy...
I got a hunch it has something to do with whatever alloy Webra uses reacting w/ the chlorine and elevated temperature.

I was just remembering the O.S. .60 I soaked in jewelry cleaner...
I have a vibrating (not quite ultra-sonic ) cleaner for jewlery / silverware that came with a quart bottle of this blue liquid that smells like home permanant solution my mom and sisters used to use. I think it has peroxide in it? Anyway...the O.S. has a similar gray color to it now, almost the same as your Webra, but a "flat" gray...

That was the first and last engine I did in that cleaner...now I stick with the crock pot 'o antifreeze.

That jewlery cleaner does clean surface rust off of steel parts like cranks, bearings, etc. very well though.

Even with anti freeze, you cannot boil it. You just want it hot.

Yep I agree about not boiling it in anti-freeze, it will turn black and its hard to scrub off with cleaners. That happened to some other parts I had when I first bought my cheapie crock pot and was not used to the heat settings.

Ultrasonic cleaners are one of those items I always wish I had but always on the bottom of the need list, and I never really come across the solutions seperate, because I've always wondered how they would act alone on rust and other oxides. Its good to hear you have good luck with it on the rust in bearings. Thats something I will keep in mind.

I sprayed and wiped down the case with WD-40 so far with nothing comming off in my rag, thinking I would start with the mildest of chemicals this motor will commonly see. With it being a boat motor, WD-40 is used quite commonly as a flush agent after a dunk. The hull for this motor isnt started yet so it will be awhile before I learn what effects nitro and heat will have over time. If it starts to come off I will have to try and remove at least internally so it doesn't wear the piston.

The heating and air conditioning trade have what they call a de-smutting agent that will strip aluminum down to a bright finish after a round of corrosion, but it would take hunting some down and dont think its very inexpensive or sold in small quantities but thats a thought. Who knows what happens to sizes though when that is done. I'm pretty sure it is simply an acid. I dont know of any other types of "etching" agents to remove contaminates or oxides without having to scrub.