Engine clean up and Paint or Powercoat?

crackerman

crackerman

Been Around the Block
Hey now,

I'm in the process of rebuilding my 80 KZ750 twin engine. I've pulled the top end apart and will be replacing the pistons and rings. I've done a decent job of cleaning up the engine but it's tough to clean between the fins on the cylinder block. I'm thinking about using the sand blaster on the piston jug, but everything I've read says to avoid the media blaster on the engine parts.

Just looking for some suggestions or ideas for cleaning the engine before paint or powdercoat.

thanks
 
I've always wanted some secret to cleaning the fins like a mad man. But I don't think there is one, other than getting into it like a madman yourself.
Are your parts greasy and filthy with skunge or are they just a gnarly dry whitey coloured metal?
Mine is greasy as hell so I gave it a good clean up with kerosene first to get rid of all the gunk. Used 3M scotch pads, tooth&wire brushes in between. Once it dried up it still looked horrible and a light white patina formed, so I'm currently in the process of Dremelling the fek out of it.
Seem to be the standard procedure around here.
If you've got the money, I don't see why you can't use a soda or other media blast on the topend?? I guess there are always pro's and con's either way.
I wish I could go to bed, wake up the next day and magically have it all cleaned up. My rig was 72 enduro and was only ever used on private property farmlands. When I first picked her up she looked like yetti's dick. I'm still far from home with this project...
Good luck man!
 
If youre having the parts professionally painted, or powdercoated just clean all the loose crap off. The shop doing the work will get them proper clean.
 
Bead blasting is fine on engine casings - as long as you get all the media off them afterwards.

And the jury is out on whether it's a good idea to powder coat air cooled engine cases / cylinders / heads. Some say it's not a problem, others say the PC holds in too much heat.

I tend to err on the side of caution and just use engine enamels myself.
 
At one time my "day job" involved the building of Road and race V8's.

The process was always the same - in the parts washer [ or outside with a steam cleaner if really gunged and greasy ] then aquablast. Before we got the aquablaster we used sandblasting. Thorough cleaning out with air blast and final run through the parts cleaner and oil passage cleaning rods. We used a variety of paint finishes, but never powder coating. PC would have been OK, but we didn't have PC plant on site, so spraying was quick and simple.

I built several bikes during this period, and all bike engines went through the same process.

If pros are carrying out the work - they know what they're doing. If you have the parts blasted to paint back at home make sure everything is totally cleared of the media - then do it all again, several times!

Later in life I found myself using aircooled VW powertrains [ there I admitted it ! ] in our Porsche Speedster and 550 Spyder replicas - they presented the same sort of cleaning problems as a bike engine. Most engines were completely refurbed - so the above processes were employed. However,once when time was really against us we used steam cleaning on a fully assembled engine prior to painting and the results were very good.
 
Thanks all for the suggestions.

Yea smvirili got a nice combination of grease and caked on smegma all over the fins. I think I'm going to take my chances and media blast the cylinder jug. Not sure if want to take my chances with the cylinder head as there a bunch more holes for the media to find it's way. Definitively gotta pickup a parts washer. I've got a powdercoat gun and I picked up some high temp powder that I've used on my exhaust heat shield so I'd like to try that out. I'll let you know how that goes.
 
Another option, and let me preface this with a BIG "Ive never tried this, but old timers tell me it works", is to plug any small holes with heavy wax. Blast the piece, than bake it to melt the wax away. Again, I have never personally never done this, but some of the old HD gusy I talk to swear by it.
 
the best way to keep bead from staying in the engine is to thoroughly wash and degrease the parts before blasting, glass bead will cling to oil and grease, then dissolve once the engine is full of oil and hot again
 
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