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Rehabilitating Cox engines

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Old 06-18-2006, 11:50 AM
  #1  
dkurtz
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Default Rehabilitating Cox engines

So, I have a couple of 049s which haven't been used in years (decades in some cases... I don't get out much) and they've pretty solidly gummed up. I'm wondering if there's a method of cleaning them up in such a way that if they're not used for a while (like over a winter or two) they don't get sticky again. I completely cleaned one up one time using old glow-fuel as a solvent, but again after a few years of disuse this one is sticking up again. Perhaps glow-fuel isn't the right solvent, since it contains castor oil, which I guess is the stuff that's solidifying over time?

Any suggestions appreciated.
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Old 06-18-2006, 12:04 PM
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Default RE: Rehabilitating Cox engines

Fuel is a good way to get them loose but for storage many use an "after run" oil such as air tool oil or automatic transmission fluid.

George
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Old 06-18-2006, 01:25 PM
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Default RE: Rehabilitating Cox engines

GCB has that right. The fuel will get them loose, afterwards you need to oil them up, a couple drops into the cylinder/piston port, and into the intake , and then pull it through the engine by prop flipping a few times. If a reedy, a drop on the intake, then flip her over to pull the oil into the reed.

If they are very gummed up, I would tear the motor down for piece by piece cleaning.

To store, Ziploc them.

Finally, when using the fuel to loosen, avoid direct skin contact as much as you can. Wipe the fuel off your hands. Fuel is a bad thing to play with, treat it with care.
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Old 06-18-2006, 01:29 PM
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Default RE: Rehabilitating Cox engines

dkurtz: Soak them in fuel or de-natured alcohol followed by a thourgh cleaning. You will probably have to tear them down for this. Then oil them (I used non-detergent 30wt) ATF works fine. Your right it's the castor that getting gummy.

HTH - Steve B.
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Old 06-18-2006, 03:36 PM
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Default RE: Rehabilitating Cox engines

If you are going to take them apart any way, loosen them up with something like wd-40. You may have to ease the head off and put some kind of oil or solvent into the cylinder to loosen up the piston if its stuck tight. You can then simmer them(boil them slowly) in water and a small bit of detergent to melt and soak away all the gum and varnish. Oil good when reassembling. I'm sure the ziploc starage idea would work well. I use small plastic containers with snap on lids that seal tight.

I used to just wrap my engines in an oily rag for storage. This worked fine when I used them freguently. Then I left three cox engines stored in oily rags for an extended period of time and the fuel residue stuck them very tight. Now I believe in after run oil and air tight containers if I'm storing them for more than several days.
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Old 06-18-2006, 04:03 PM
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Default RE: Rehabilitating Cox engines

For after-run oil, I have used some Hobbico after run oil with good results. However, judging by the colour and odor (a nice minty freshness!), it appears to be just Marvel Mystery Oil from Canadian Tyre which is cheaper to buy, and you get more. It seems to work well for me any ways. (Plus you get a nice smoky startup for those scale models that are suppose to have radial engines!)

Chris
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Old 06-18-2006, 07:19 PM
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dkurtz
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Default RE: Rehabilitating Cox engines

Thanks for the suggestions. I think I'll try the de-natured alcohol on one. And I found a place nearby that has the Hobbico oil (I don't think the Canadian Tyre stuff's gonne be too easy to find here around Chicago <g>.)
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Old 06-18-2006, 08:34 PM
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Default RE: Rehabilitating Cox engines

Marvel Mystery Oil can be found anywhere. Walmart, parts store, etc. It's good for so many things, I can use a quart bottle pretty quickly.
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Old 06-18-2006, 08:38 PM
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Default RE: Rehabilitating Cox engines


ORIGINAL: dkurtz
<snip> .............(I don't think the Canadian Tyre stuff's gonne be too easy to find here around Chicago <g>.)
Marvel Mystery Oil can be found at many Walmarts and almost any self-respecting autoparts store.
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Old 06-18-2006, 08:46 PM
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Default RE: Rehabilitating Cox engines

Actually, MMO is probably a lot easier to find in the USA . I had a HECK of a time trying to find somewhere that carried it in the Vancouver area.
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Old 06-18-2006, 10:14 PM
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Default RE: Rehabilitating Cox engines

HOPPES gun cleaning solvent, and get some bore brushes and swabs while you're at it, too. This is good to use while you are running COX engines on a regular basis, too if you are looking for every last R that engine has to give. They have snow mobiles in Canada, eh? They have specialized storage oils for snow mobiles that work great for our engines. Air tool oil is good, too.
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Old 06-18-2006, 10:40 PM
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Jim Thomerson
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Default RE: Rehabilitating Cox engines

Regular Marvel oil will create hard red gunk on extended storage. I understand Marvel air tool oil is fine. Rislone is the best, on the shelf near the Marvel oil.
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Old 06-19-2006, 12:39 AM
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Default RE: Rehabilitating Cox engines

ORIGINAL: Jim Thomerson

Regular Marvel oil will create hard red gunk on extended storage.
Guess I havn't stored any engines long enough for this to happen! I will have to watch out for that.

CP- <sigh> yes, we do have snowmobiles up here in the frozen north. I guess I am suppose to say 'eh' now.
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Old 06-19-2006, 03:50 AM
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Default RE: Rehabilitating Cox engines

One thing more you might try is heating them up. You can put them in a toaster oven or just hit them lightly with a torch. It seems to unstick them and let in the solvent (fuel or oil).
I would only use the heat um up method if they were very stuck and would always take them apart and clean them after the heat.

I use heat when the pistons are so tight that they won't come out of the barrel, that way I don't have to use so much force that they are damaged from being disassembled.

MR Flyer57
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Old 06-19-2006, 07:53 AM
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Default RE: Rehabilitating Cox engines

Marvel Air Tool Oil is MMO with an added rust inhibitor.

George
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Old 06-19-2006, 08:23 PM
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Default RE: Rehabilitating Cox engines

IFF, an Eskimo is on a long ride across the frozen tundra, and his machine starts spewing oil all over the place, so he pulls in to the first repair shop he sees. A Canadian mechanic comes out, looks at the snow mobile, then looks at the Eskimo and says," Blew a seal, eh?" The Eskimo says," No, that's just ice on my moustache".
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Old 06-20-2006, 12:35 AM
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Default RE: Rehabilitating Cox engines

havn't heard that one! not really on topic though CP!

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Old 06-20-2006, 09:27 AM
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Default RE: Rehabilitating Cox engines

So, now I'm confused. Is Marvel Mystery Oil the way to go, or does it really gunk up as well with time?
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Old 06-20-2006, 10:07 AM
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Default RE: Rehabilitating Cox engines


ORIGINAL: dkurtz
So, now I'm confused. Is Marvel Mystery Oil the way to go, or does it really gunk up as well with time?
Some have had trouble with MMO gunking up. If you place it in a zip-lock type bag after it's oiled you will not have this problem.

I prefer an air tool oil to MMO because air tool oil has rust inhibitor. The one I normally use is Campbell-Hausfeld...just because I can get it easily. These type oils and "after-run" oils are for short time storage mostly.

If you are putting the engine in storage for years, you might consider Rislone (yellow container) or one of the automatic transmission oils. I generally wrap the engines in a paper towel or cloth after oiling, but I think the baggie is perhaps a better idea.

Avoid some of the "exotic" oils. Some may damage the engine or glow plug.

If you have stored an engine for a long period, it is a good idea to remove the plug and backplate and flush it with some denatured alcohol or fuel to get residual gunk, and especially any suspended rust out of the engine when you return it to service.

Of course these are only opinions, there is seldom only one way of doing things.

George

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Old 06-20-2006, 10:25 AM
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Default RE: Rehabilitating Cox engines


ORIGINAL: combatpigg

IFF, an Eskimo is on a long ride across the frozen tundra, and his machine starts spewing oil all over the place, so he pulls in to the first repair shop he sees. A Canadian mechanic comes out, looks at the snow mobile, then looks at the Eskimo and says," Blew a seal, eh?" The Eskimo says," No, that's just ice on my moustache".

THAT is, Really really funny.!!! LOL

RE: Rehabilitating Cox engines: .What I do is, continually Tap them on the HEAD, with a COX wrench, until the engine finally submits,and ,Sees things my way.After an hour ,of that kind of treatment, they tend to," learn their lesson "and never misbehave again.[>:]
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Old 06-23-2006, 10:15 PM
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Default RE: Rehabilitating Cox engines

I have a cox .049 that i havent run in about 8 years. I am looking foreward to tapping it into submission.ha ha I learned a lot, i hope to put some of the ideas to work. Thanks
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Old 06-23-2006, 10:30 PM
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Default RE: Rehabilitating Cox engines

Instead of tapping, can't we soak it & set it in front of the stereo speaker, and crank up some Deep Purple organ music to shake some sense into it... for about a sixpack or so. If you play Perfect Strangers loud enough, that stuck engine might start by itself.... or your drywall will buckle and your fillings fall out. Well, just one way to find out
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Old 06-23-2006, 11:35 PM
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Default RE: Rehabilitating Cox engines

LOL HAAAAAAAaaaaaaaaaaaaHAhHaha. Maybe some Chinese water torture ???Set it in a DARK corner ,of the Basement,Turn up that music, and, Drip water, at increasingly ,slower intervals, on the cylinder head.If that don`t work, Sharpen up, a Bamboo SKEWER,Slip it under the Reed ,and slowly force it in,untill that engine starts, to SCREAM AGAIN.Don`t stop ,untill you get the RPMs you need[>:].Just call it "TOUGH LUV".
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Old 06-24-2006, 04:24 PM
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Default RE: Rehabilitating Cox engines

If you use the stereo idea put on some really crummy music and maybe the engine wil start up just to get away.
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Old 07-07-2006, 03:08 PM
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Default RE: Rehabilitating Cox engines

The only problem with Hoppes is that it'll take the coating off the metal fuel tank backs. I was thinking of giving carburetor cleaner a try myself.
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