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Engine basics => Engine set up tips => Topic started by: Dan Labine on August 26, 2009, 07:35:44 AM
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I just bought a TD 049 off Ebay. Big mistake!! The seller said it had excellent compression. It turns out that the engine is gummed up so bad that it wouldn't turn over. Seized up tight. I have soaked it in fuel and it has loosened up enough to get it apart.
Now how do I get the cylinder cleaned? It appears that the castor?? has stuck to the cylinder and piston. What should I use to clean it off? Any suggestions???
Dan
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Find some real fine lapping compound. Alternative is the old fashioned toothpaste. Take it slow in removing the varnish. I have even resorted to some 1000 grit polishing paper. DOC Holliday
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The more traditional method of "de-varnishing" the Cox TD cylinders is to use fine steel wool. No, it doesn't scratch the cylinder. ake sure you wash the part after this operation (in soap and water). Don't mess with the piston.
Floyd
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Dan, sometimes gummed up isn't a bad thing. At least this way you know it was run using castor. There may be a chance that the engine was fine prior to storage. I've purchased many from Ebay and found that typically the only problem is a cracked carb body. This can be fixed easily by getting a piece of what I think is 3/8 K&S tubing and cut and file it to fit around the neck and epoxy it on. I usually use denatured alcohol to clean and soften castor. The Davis Diesel brush is designed to clean the bore of the cylinder and works well. Since you already have it apart check the ball socket and repeen if necessary. Ken
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Thanks for all the advice. Where would I get the Davis diesel brush? The engine is now free but the cylinder is pretty gummed up. I will try honing it out with tooth paste..
Hopefully I can resurrect it...
Dan
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Dan, I wouldn't try and lap that cylinder if its not necessary. The steel wool 0000 is what Cox recommended in their instructions. It stated to use a little light weight oil in addition. The Davis diesel brush is available on Ebay for about $6.95. Its not a needed item just a valuable maintenance tool just like the piston reset tool. Keep in mind that Xenalook is providing high compression plugs now. If the engine is gummed up like you've stated, hows the crankshaft? I've needed to seperate the drive plate off the crank and polish the crank up. I've had the castor gum act as a brake and wouldn't let the engine come up to rpm's . This can also lead to overheating. That stuff is a great preservative but can really dampen engine performance. After I have the crank out I chuck it in my drill press and use 2000 grit and oil followed by metal polish. Its probably more than adequate just to remove the castor varnish for good performance but I take it another step. Ken
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Hi Ken.
The crankshaft freed up as soon as the piston and cylinder let go. It appears to turn freely but there is some discoloration on the shaft. I've gone this far so I may as well keep going. I will remove and clean everything. In fact I'm kind of enjoying this. Its fun to tinker. Hopefully I don't go to far and completly ruin the engine..I checked ebay but there are no brushes available right now. I will keep looking. Thanks for the help..
Dan
Dan
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Abrasives and engines always scare me. Especially little engines. I free up my Cox's with a heat gun to soften the gunk! Beware of melting the plastic parts. I've never done this but some are more heavy handed than I. When I get the parts moving the addition of Penetrating oil, or Jus ol' Cox fuel will free up all the parts.
W.
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Dan, this is the website, www.DAVISDIESELDEVELOPMENT.COM. E-mail address is DMPDDD@AOL.COM. The stock # for the brush is dvb049. In the event your taking the crank apart I might me able to add some helpful hints. First, I use a 5-40 allen screw to take it apart. If you tap the stock screw it will more than likely bend causing problems later down the road. I then made a spacer with a hex on it. You could use a piece of tubing and a adequate size nut. I slip my spacer over the allen screw and insert it into the crank. I then turn the allen with the appropriate wrench while holding the hex on the spacer with a wrench. Of course you have to line the splines up accordingly and it will draw right onto the crank and bottom. This method assures that your driveplate is square after dissasembly. I mentioned not lapping above due to the fact that the tee dee already has a tapered fit. The sealing is done by a slight pinch at the very top of the cylinder. This is needed sometimes when the engine is new but due to the fact its already been used I would just do a suitable cleaning. I myself have noticed the discoloration on the crank as you mentioned. My method of polishing the crank almost entirely removes that staining. Another valueable tip is to make sure that the little holes in the venturi are clear. The holes if your not sure are located just above the threaded portion of the venturi in the recessed area. A small straight pin or fine wire does good there. Now if I can only get mine to run. Ken