I have a TH .40 with years of gunk on it. It runs great, but looks like crap. I don't think the extra gunk in the cooling fins helps the cooling much either. I have the engine completely disassembled and I've stuffed pieces of rags in the cylinder and crankcase to keep as much of the sand out as possible I only intend on blasting the block, head, and muffler. Is this OK? Is there any other prep work I should do?

I guess it would work. Most guys simmer theirs in anti freeze in a crock pot. It will make it look like new. Just be sure not to use the crock pot for food ever again.

David

Don't do it!!! In addition to removing metal, sandblasting both stretches and hardens the metal surface & can distort the castings aside from the risk of the grit getting into places that you may not get it out of.

Simmer the engine in antifreeze

I have glass bead blasted a few Super Tigers. It worked very well. But the beads were fine and it left a finish very much like what was on the engines from the factory. Make sure you blasting media is not contaminated with other things like larger chucks, Iron powder, etc. I bought a used Super Tiger and someone had Sand blasted the muffler. It had a really coarse finish on it. It didn't look original.

Enjoy,

Jim

I too have bead blasted engine exteriors, with excellent results. But you must make absolutely certain that the glass particles cannot get into the cylinder bore, or into any threaded areas, etc. Tape off and plug with rags every opening. Afterwards, carefully remove the packing and wash with a detergent and toothbrush to remove any of the remaining dust and particles.

IMO sand, even very fine silica will be too coarse for a decent end result, but many factory engines receive a glass bead blasted finish anyhow, so if you do it carefully it it fine.

AJC

I have glass bead blasted a gasoline conversion engine before. It did a really nice job of taking the paint, grease, grime off the original saw case. It also cleaned up the cooling fins on the cylinder. I was pleased with the end result.

I completely stripped the whole engine first. I taped the holes in the cylinder closed to avoid ruining the chrome inside. I blasted the entire outside of the cylinder and the entire outside of the case.

I cleaned the whole thing in kerosene with a soft plastic/nylon brush. Then I gave the whole thing a shot of carb/choke cleaner and then let it air dry.

Reassemble and go fly.

I'd take the bearings out, if you haven't already. But the antifreeze in the crockpot method is much easier, and less potentially harmful to the parts. I've done 50+ year old engines, and they come out looking almost new! Just a little scrubbing w/ an old tooth brush to remove the loosened crud after soaking over-night in hot antifreeze. Not boiling, but just to the point where there is the slightest bit of steam rising off the surface. It's best if you do it in a garage or shed, or where the smell won't bother anyone...You can get a cheap "slow cooker" at wallyworld for 10-15 bucks, and devote it to just cleaning engines.
One thing tho...If you show your buddies how neat and clean your engines look, they'll be wanting you to do theirs! I charge a few bucks to do it now

When you use anti freeze,do you use the stuff that comes concentrated or just the ready to use stuff? As a fellow flyer has tryed car coolant and said it didnt work very well for him.I'd like my 46 to look new again as its out in the open in a funstar and it is just a brown mess.

yes! don't even think about leaving the bearings in. and some engines are even ugly when new and can benefit from a little bead blasting.

reattach the head, backplate and muffler with old screws, install an old plug and plug the carb, muffler and front bearing holes with corks or rubber stoppers. any machined finish like cylinder fins on some engines should be wrapped with tape or they will lose their shininess.


dave

Hey Vortec, Im reading this thread thinking, "what sort of antifreeze do they use in the USA" after SteveG's comment at the meeting. Then I find youve already asked the question.

There is like three or four types of antifreeze in the US now. I think you should use the original full concentrate polyglycol fomula for cleaning engines. Another trick is to soak it in methanol or fuel for a few days.

As far as anti-freeze type, use the good old green stuff straight from the bottle, un-diluted. I don't like the idea of having water in it because sometimes I drop entire engines in there without taking them apart. Sometimes I just take the plug out, and maybe the carb.(if plastic) and backplate. Flush it out after w/ carb cleaner, or brake parts cleaner, and then run it awhile on the stand, then after run oil...

I have used white spirit on a toothbrush with excellent results.

I cleaned my Fox .74 Diesel the other day, my first try using the crockpot and antifreeze method, I put it on high for about 5 hours with the bearings in it and no problem, it came out spotless. I had removed the sleeve and head and separated the cylinder part of the crankcase. Immediately upon removing it from the crackpot, too hot to touch, I doused the bearings with Corrosion X to protect them while they cooled and dried. Now it's back to being clean and ugly as Davey said above. It has been a genuine workhorse for about 3 years as a glow and 10 years as a Diesel.

Sandblasting works great on engine parts if you use the right type of material. Glass beads for one works great on "full-size" auto engine and will not surface harden even soft aluminum parts as long as you don't crank up the air pressure too much. I've done that many a time on aluminum, steel and iron engine parts. Walnut shells are probably the most gentle on soft metal parts but don't last long before turning into dust.

The response about the walnut shells brings up a question. Has anyone tried tumbling engine parts in a brass tumbler with either corn cob or walnut shells? I know the antifreeze trick works great but I was just wondering if the tumbling would have any effect at all.

Well, I guess patience is a virtue. I posted this question and when ahead a blasted my engine without seeing the results. I did use sand and it cleaned the engine up nicely, but I had a hard time getting the sleeve back in the cylinder. I am 99% certain that I got all the sand out, so I guess as Britbrat said, I may have warped the block. I got it all back together, and it turns over fine. I wonder if it will do any damage to start it? And if it will, is there anything I can do? This is an OLD .40 so if it is a total loss, I won't be devastated.

Thanks for the replys guys..Ill try it tomorrow.

I wouldnt sand blast as it is to much trouble i think..I done my os 46 and 50sx this morning in anti freeze and it worked like a charm..Look brand new and only boild them for about 30mins..Pic only shows how dirty the 50 was but the 46 was in just as bad..And the assembled motors after cleaning.. Pitty the 50 is going back behind it extra's cowl.

In certain cases, the bead blasting will be the best choice (if done properly).

I acquired a Saito 80 that was nearly new inside, yet from sitting in a damp location was very coroded and pitted on the exterior and the chrome was peeling off of the rocker covers.

After a thorough bead blasting (with everything dissassembled and blocked off as I suggested above) the engine looks great.

Its definitely not the solution for everyone, but when you have surface "damage" (like the severe aluminum oxidation, or marking up, etc) it does the trick well.

AJC

well im trying the crockpot thing on my engine. i just found my os 61fx in the pond after 1yr 1/2. pretty much a mess. the good thing is that i put transmission fuild in it after i got it home. i got the motor apart after a few hours. i will let yall know how it comes out.

Gravityisnotmyfriend, you posted a long time ago: So what happened with that engine?

Well i have it cooking in the crock-pot for 24 hrs to see if it will come clean. most of the gaskets are gone but the orings are still good. what was mind blowing was the front bearing, it was in great shape, no rust or corrosion on it. the back one was gone. i planing on putting new in and getting new gaskets for it. piston and sleeve was in great shape. will let you know how it comes out.