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Author Topic: Restoring old engines questions  (Read 1302 times)
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radioman
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« on: November 02, 2011, 03:25:07 AM »

The other day I cleaned up my workshop and discovered I have six engines which haven’t been ran for at least 25 years which includes 15 and 32s. 

Looking for suggestions on best way to bring them back to life.

What should I soak them in before disassembly?  Once cleaned, etc. what fuel would be best? 

A couple are going to need glow plugs so will have to locate a source.

Thanks, Stan
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TimWescott
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« Reply #1 on: November 02, 2011, 01:16:07 PM »

I wouldn't soak them at all before disassembly, unless they're too tight to come apart.  In that case I'd start by trying to warm them up (castor oil gum loosens with heat), then I'd try isopropyl alcohol.

Once they're apart, crock-pot them in antifreeze (Google it) overnight.  Then clean them up with an old toothbrush & reassemble with after-run oil.

The best fuel depends on the engine.  Check the manufacturers recommendation, but if they're iron piston/steel sleeve engines then you want to run lots of oil, and at least a good part of that castor.
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wreckbender
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« Reply #2 on: November 03, 2011, 02:33:42 PM »

This came up on our swedish forum recently: http://www.svensktmodellflyg.se/forum1.asp?viewmode=1&msgid=263679&page=&CurrentMainTopic=3&replypage=99 it´s an article from Model Airplane News
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greggles47
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« Reply #3 on: November 05, 2011, 05:57:29 AM »

I'd give them a bath first in a crockpot full of antifreeze. For particularly disgusting engines it might take a week of them bubbling away to get rid of the accumulated gunk!

After a good soak, they'll come apart a lot easier, and generally because of the castor used, the internals should be ok. Strip them down, check/replace races check Piston/ cylinder fits and then you can decide whether they are worth reassembling and running or just show pieces.

Good luck with them!

Before & after pics would be good too.

Fuel will depend on what motors they are, plain bearing about 25% oil - Ball raced motors 20% oil to start with. Nitro? whatever you're comfortable with start about 10% isn't going to do any damage.

Plugs should be available at a local hobby shop - If you don't have one try Merlin plugs.

Regards

Greg
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Geoff. Potter
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« Reply #4 on: February 16, 2015, 08:51:26 PM »

Another important aspect of stripping engines to clean and relife is to make sure they are marked CLEARLY on each part , front or  back , particularly piston ,liner ,and rod .
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ffkiwi
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« Reply #5 on: February 16, 2015, 11:37:23 PM »

I would hesitate to recommend antifreeze as some types can act as paint stripper-and also have funny effects on plastic carbs, venturis and O-rings.  The best method of loosening up is heat-this works well regardless of whether the engine has been sitting for 6 weeks or 6 decades!  You have a choice of using a heat gun, a torch, or a domestic oven-personally I use one of the small domestic bench top ovens, set to about half max temp, for 15-20 minutes. Then you remove the engine, fit a prop and gingerly attempt to move things using the prop to provide the movement force-unless there is some mechanical problem-such as a bent rod, or a gudgeon pin jammed in a transfer port, this sort of treatment with start things moving-THEN hit it with WD40, CRC 5-56 and keep wiggling till you get it turning over a full revolution-(if it is a diesel, someone may have screwed down the compression so far it cannot be turned over TDC-a gradually application of force should save you from bending anything in this event-obviously back the comp off if you can't get it over TDC when it is freed up.)-then get some oil in there and keep going till it fully frees up. If you intend to dismantle-as distinct from simply freeing up, then start unscrewing any screws whilst it is still hot-the heat will have softened any castor gum and the screws will turn a lot easier than when cold. This presumes of course that (i) you removed any plastic parts before putting in the oven and (2) that the screw heads have not been munted by a previous hamfisted operator....

 ChrisM
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OZPAF
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« Reply #6 on: February 20, 2015, 06:51:34 PM »

I recently cleaned up an old Frog 150 by boiling it in a dilute mixture of detergent and water for around 20 mins or so. It freed up nicely and when dry I immediately oiled it. I only removed the back plate.

No problems running it after that.

John
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easytiger models
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« Reply #7 on: February 20, 2015, 07:26:07 PM »

I would hesitate to recommend antifreeze as some types can act as paint stripper-and also have funny effects on plastic carbs, venturis and O-rings.  The best method of loosening up is heat-this works well regardless of whether the engine has been sitting for 6 weeks or 6 decades!  You have a choice of using a heat gun, a torch, or a domestic oven-personally I use one of the small domestic bench top ovens, set to about half max temp, for 15-20 minutes. Then you remove the engine, fit a prop and gingerly attempt to move things using the prop to provide the movement force-unless there is some mechanical problem-such as a bent rod, or a gudgeon pin jammed in a transfer port, this sort of treatment with start things moving-THEN hit it with WD40, CRC 5-56 and keep wiggling till you get it turning over a full revolution-(if it is a diesel, someone may have screwed down the compression so far it cannot be turned over TDC-a gradually application of force should save you from bending anything in this event-obviously back the comp off if you can't get it over TDC when it is freed up.)-then get some oil in there and keep going till it fully frees up. If you intend to dismantle-as distinct from simply freeing up, then start unscrewing any screws whilst it is still hot-the heat will have softened any castor gum and the screws will turn a lot easier than when cold. This presumes of course that (i) you removed any plastic parts before putting in the oven and (2) that the screw heads have not been munted by a previous hamfisted operator....

 ChrisM
'ffkiwi'

What he said.  Unless the engine is so gross that it needs a crockpot cleaning...don't do it.  Just heat, a heat gun, usually frees up most engines, and no dissasembly is required...or suggested.
If you are looking to clean things up so you can have perfect engines for display, that's another story.  If you are looking to USE them, just free them up with heat.
You CAN do damage to some parts with antifreeze, just like kiwi said.
been there, done that, ruined enough engines.
Also, laquer thinner dissolves castor well, and is less corrosive than antifreeze.  Still will melt some plastic parts, though...
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Dave Andreski
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« Reply #8 on: February 21, 2015, 10:44:04 AM »

Isn't it also advisable to turn the prop so the connecting rod is pushing the piston, NOT pulling?
Dave
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ffkiwi
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« Reply #9 on: February 21, 2015, 01:36:44 PM »

Not necessarily-as in the example I gave earlier of a diesel that has had the compression screw wound in too far-the engine will not turn over TDC-so turning the prop to push might result in damage to the rod, gudgeon or shaft if done with too much force. [of course if it is your own previously used engine you can be a bit more free handed assuming you recall the details of how it was last run....]   What I do-after heating as outlined previously-is fit a prop (carefully-the engine is too hot to hold in your bare hand after all!) tighten the prop nut/screw and then attempt to move the engine by turning the prop back and forth through a small arc-about 30 degrees-if it moves then I'll gradually increase the degree of movement and add some CRC to encourage things until I've got it passing through BDC freely-which also means-now that the piston is at its lowest level, you cam drop a few drops of oil in through the exhaust port(s) and wriggle things a bit to distribute it. Then I'll attempt to turn it over TDC-once that has happened successfully then I'll start flicking it over to distribute the oil and free things up. Depending on the aim of the procedure-simple freeing up versus stripping and cleaning, I'll either oil and wipe down, or start the stripping process whilst still hot-taking particular care with things like heads and backplates to preserve gaskets wherever possible by rotating these components back and forth on their seating locations before any attempt is made to remove them. This usually-but not always-works. Head gaskets-especially the composition ones common in the 1950s and 60s-are usually problematic-ie K&Bs, OS, McCoys etc

  There are always ones that 'get' you-one that frees up-but is stiff over BDC-usually indicates a bent rod or gudgeon-but can sometimes (especially with diesels that screw the cylinder into the case, and the fins onto the cylinder) indicate distortion of the cylinder caused by overtightening. A motor that won't move at all-even the slightest-usually means the gudgeon has moved sideways and is trapped in a transfer port. This is where you are allowed to swear loudly and extensively.....as you're in for a long frustrating effort-if indeed it can be rectified. [I once had this happen with a Cox Special 15 that was built up from parts-not realising that the thread start location is absolutely critical on these engines to ensure the exhaust is always exactly located rhs, and parallel. If not-what did happen can happen-gudgeon worked out into one of the transfers. That particular incident took hours of fiddling through the backplate with small curved tweezers to try and coax the pin back into place BEFORE I could even start to unscrew the cylinder....

  ChrisM
  'ffkiwi'
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C/L Gee Bee
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« Reply #10 on: July 24, 2015, 09:13:56 PM »

I found an O.S. Twinstack, a bargain for its price. It was stuck, dirty from years of castor oil and dirt, but a 'diamond in the rough'.
Disassembled head, back plate, and needle valve assy, then into crock pot it went.

Two days later...removed it from the Glycol/water mix, the aluminum was etched and overall black. I attempted to polish spots that were 'reachable', but the finish was blackened and some places 'powdery'...
I used quality Glycol Anti Freeze, as always...NOT the cheap stuff.

Other than the Twinstack, my Crock Pot baths had always turned out shiny and squeaky clean pieces.
My wife bought me another O.S. Twinstack from a MECA member, on my 68th birthday.
The "Offenhauser" of 'B' Team Race.
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FLYBOY49
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« Reply #11 on: May 08, 2016, 03:48:41 PM »



I have a friend in need of prop spinner nuts for D C small engines.  Any suggestions where such can be obtained?

van...

Direct e-mail: vander_e@hotmail.com
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