Honda-SOHC
Other Stuff => Misc / Open => Topic started by: Raygun on March 18, 2021, 11:54:37 PM
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Getting deep into my engine teardown now on two CB550 engines and rebuild so getting to the stage where I am thinking about what route to refinish.
From what I read, vapour blasting seems to be liable to corroding pretty soon after it's done; how do people stop this- applying a clear varnish or other finish?
Also, do the engine casings have to fully disassembled before they can be blasted? Can engines be blasted assembled? I've stripped down the top-end, avoiding doing the bottom end if I can avoid it but would like to refinish the whole engine casing to bring it up to a 'new' look.
Had a quick search in the forum and couldn't find anything; though if this has been covered before my apologies!
Thanks all!
R
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Don't vapour blast your bottom end without dismantling. It's done with a powerful water jet with and an abrasive media mixed in. Any abrasive getting into your engine will ruin it.
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If the 550 is the same as the 500 the top end would be painted silver.
Here is what I did to top end on my CB500K0 to bead blast it to stop bead ingress. The pic was after the 1st' blasting. I then repeated with brand new media and blasted with compressed air line and then washed down with acetone to clean and the blasted again with compressed air. Motley collection of non-standard bolts/threaded rod etc to hold together/seal.
Poo pooed by some on here I know but there ya go. ;D
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Unfortunately the top end on mine has been very badly sprayed black- so I'm erring to removing it and I hoped blasting would do that.
The overspray is hideous, it's in the inlets!
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How would you clean out an assembled bottom end with acetone? Don't try it you will ruin the engine, the only way to do it safely is to take it apart.
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The blasted surfaces are usually painted with Simonize VHT paint and baked in the oven. Simonize serial number SIMVHT31D.
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Thanks for the paint serial- I'll use that if I keep the black finish on the engine.
If I want to keep the 'factory' silver look after vapour blasting how best do I go about preserving that finish?
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The SIMVHT31D is the silver, not the black.
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How would you clean out an assembled bottom end with acetone? Don't try it you will ruin the engine, the only way to do it safely is to take it apart.
I never said anything about bottom end !
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Sorry Ash, I wasn't directing that reply at you. The original question was about vapour blasting the engine cases without dismantling. Didn't want him to get confused there. On reflection I could have worded that reply better.
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You should never vapor blast any engine parts with bearing surfaces. This link may help http://www.sohc.co.uk/index.php/topic,20419.0.html
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I have used Sutton Soda blasting in the past. i found them to be very good.
I think they can do a whole engine.
Whith no danger from stray blast media
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This was a complete twin cyl. engine minus, all internals, I blasted with a positive pressure maintained on the inside of a few PSI, after checking it was completely sealed.
Not done any of my plain bearing crank engines like this though.
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I have had four engines vapour blasted in the past and never had any issues BUT.....you must strip the engine to the bare castings. You will also need to clean and clean and clean again all the castings when you get them back paying particular attention to the oil galleries. I use my parts washer to clean the castings followed by hot soapy water from a garden pressure bottle (the type you pump up). I then used compressed air followed by a quick stint in the oven at 30 deg to dry everything out.
If you live in London I can recommend a company in Penge called I Cleenz Machinez run by Peter and Caine. They do this work for a living and they know what they are doing.The finish they leave on the cases is like a satin. On my 400/4 I didn't paint the cases, I just rub them over with ACF50 when I clean the bike, never had any corrosion. If you want the cases painted they can do this for about an extra £160 but get a quote first.
I do know someone who had a complete engine vapour blasted years ago without stripping it first. They thought they did a good job of sealing it up with bungs, bolts, mastic etc. They obviously didn't though because the engine was wrecked within a couple of weeks of refitting.
Vapour blasting is tricky and you do it at your own risk, it only takes a few stray beads getting into a bearing and the engine could end up as toast.
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Hmmmm!
The finish looks amazing, but the complexity of the bottom end rebuild is quite daunting so very much in two minds as to whether I strip the whole engine and rebuild, or just stick to the top end rebuild only.
Thanks for all the advice everyone. This forum is so useful in doing this project.