The New And Improved Unofficial R65 Forum V2
Technical Discussion => BMW Technical Q&A, Primarily R65 => Topic started by: Luca on December 11, 2013, 04:07:58 PM
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I was cleaning up an old piston to make into a paperweight or desk art for my neighbor today. I came across a pretty good way of cleaning off the carbon that I thought I'd share.
I chucked a nylon brush cup for a dremel into a drill press, and while keeping the piston head wet with carb cleaner, let the thing wisk away. The nylon did not damage the aluminium, and having it spinning at 3000 rpm or so made much shorter work of the job than if I had done it by hand. It made cleaning the valve recesses particularly easy.
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I was cleaning up an old piston to make into a paperweight or desk art for my neighbor today. I came across a pretty good way of cleaning off the carbon that I thought I'd share.
I chucked a nylon brush cup for a dremel into a drill press, and while keeping the piston head wet with carb cleaner, let the thing wisk away. The nylon did not damage the aluminium, and having it spinning at 3000 rpm or so made much shorter work of the job than if I had done it by hand. It made cleaning the valve recesses particularly easy.
I am a lazy bastard [see a good Australian Thesaurus] and whilst I applaud your work in cleaning the piston you do have the problem of your high speed brush distributing crud that you will eventually have to clean up off other things. It also takes personal effort.
My preferred method for cleaning pistons that are never going to see service again is to pop them in the bead blasting cabinet and spend a few minutes giving them a good going over. The beads leave a very nice "satin" finish. Of course I would never subject a piston I was going to put back into an engine to either bead or sand blasting and any person claiming to be a mechanic who would deserves to be hung inverted over a slow fire.
My second method for cleaning up a piston that I DO intend to reuse (or simply display) is to give it a good soaking in oven cleaner which will remove 99% of all carbon and other deposits. I then do something a bit naughty. My wife and I have a 30l bucket in the laundry which is kept filled with a super-saturated solution of "Sard Wonder Soaker" - we live in the tropics and antiperspirant build up on clothing is a big problem, so to are ink stains, grease/oil stains and in my case, more than the odd red wine stain - we soak clothes in the bucket and renew the "solution" every year or so, or when it shows obvious signs of being at the end of its useful life.
Anyway, without telling "SHE" I slip pistons (and other alloy parts) into the bucket and leave them foe a few days - they come out very clean.
A final method, whilst a highly effective cleaning strategy, unfortunately guaranteed (in my experience) to have an entirely negative effect on domestic relations is to slip assorted engine parts into the dishwasher on a good "pot scrub" setting (don't forget to turn off the "rinse aid" or "glass finish" part of the cycle). A very good way of quickly getting stuff really clean.
As I mentioned, the cause of more than one domestic, particularly when the plastic liner of our old dishwasher got indelibly stained by some oil from a diesel engine.
Still, what she doesn't know won't hurt me and when that dishwasher was replaced I made a point of buying one with stainless steel liner and baskets so no "evidence" is left behind.
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Gasoline softens up the carbon deposits well enough to easily clean them off with a brush.
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I'll have to try gasoline next time. A gallon costs less than a can of carb cleaner!
Splatter wasn't really an issue on the drill press since I got most of the flakey carbon off. What was left behind was loosened up into a sort of goo that I wiped away whilst the cleaner was still wet. Did a fine job of removing not only the heavy stuff, but the deeper "stains" in the aluminium too.
I'd thought about using caustics but was worried they (including dishwasher detergent) would chew up the aluminium and I wanted to keep the piston looking fresh. I'll have to try them on some other scraps of aluminium laying around.
I guess old kitchen appliances can have a great second life in the garage. The dishwasher for parts cleaning, the oven for baking paint (electric would probably be best), and the fridge/freezer for cooling bearings and, of course, beer!
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Has anyone tried the water injection cleaning method before stripping an engine down ?
You spray a fine mist of water into the carb intakes while holding the engine at a medium throttle. I haven't done it for years but I remember it did a reasonable job of cleaning the piston and head. If done on an engine that isn't to be overhauled it's a good idea to do it immediately before an oil change.
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Has anyone tried the water injection cleaning method before stripping an engine down ?
You spray a fine mist of water into the carb intakes while holding the engine at a medium throttle. I haven't done it for years but I remember it did a reasonable job of cleaning the piston and head. If done on an engine that isn't to be overhauled it's a good idea to do it immediately before an oil change.
I know this goes back aways but I just came across it.
I have done the water injection method on my '79 Alfa engine when I 1st got the car 15 years ago and followed the advise of a member on that board. The engine had 75K miles on it at that time and I knew not the Previous Owners or their maintenance habits.
If you keep the revs up to 3-3,500K and "mist" the water in evenly, like at the intake filter canister so that all cylinders receive an even distribution of water, you should be safe and achieve the desired results. IF you screw-up and only do one cylinder at a time, well I don't think crank shafts are supposed to bend after hydro lock.... :o :'(
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I've used heavy concentration of Chevron Techron, fuel additive to the fuel, with good results .
I usually do this, if I'm on a road trip, 20 fluid ounce, 591 ml bottle to a full tank of fuel, I have small vehicles no more than 12 US gallons, 46 l .
Driving at highway speeds, 80 mph, 130 kph for the entire tank full .
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I put a water injector on a V8 that was pinking at an even throttle because of carbon glowing in the cylinder and it solved the problem. You could advance the ignition more as well as the water stopped the pinking when you put the foot down.
The water was injected when the vacuum dropped and was measured by the revs.