Ok it's been awhile

Discussion in 'RC Onroad Forum' started by digdug72, Oct 19, 2005.

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  1. digdug72

    digdug72 Member

    Ok guys need your help, It's been 2years since I have completed a nitro ruild. I have my os .12 cz broken down. Now I am at the part where you remove the darn piston/sleeve. Ok how do you remove it without bad words or tossing you motor againsy the wall? I rember some said use the oven, but forgot how to pop it out with zip ties, any info will be greatly appreciated!!
  2. Removing the crankcase bearings
    When rebuilding a truly worn-out nitro mill, you may want to replace one or both of the crankcase bearings. After you've removed the carb, piston and sleeve and crankshaft, the only parts that remain are an empty crankcase and the bearings. The engine bearings are press-fit into the crankcase, so to remove them, you'll have to warm the crankcase in an oven to allow it to expand. Heat the oven to approximately 250 to 300 degrees F, and “cook” the engine for 5 or 6 minutes. Once you've heated the crankcase, remove it from the oven (use oven mitts!), and tap the bearings out with the end of a wooden spoon or any other non-metal tool.
    For a totally “factory” job, use a special bearing removal/installation tool such as the one from OFNA. This tool installs and removes crankcase bearings in a snap.

    Removing cooked-on residue (varnish)
    A clean engine runs cooler (and looks better) than a dirty engine. Unfortunately, engines produce high heat that can turn dirt and exhaust grime into a varnished armor that's nearly impossible to remove. The best product I've found is “Demon Clean” from Dave Gierke Flying Models; simply apply this liquid to the dirty parts and then scrub them clean. You can also use commercial-strength oven cleaner, but keep it away from anodized heads and engine parts; oven cleaner eats anodizing for lunch. If you have a rotary tool, clean the parts with a wire-brush attachment and you'll soon have a shiny finish.

    Above: Oven cleaner can be used to remove baked-on crud; be sure to protect your eyes and skin, and follow all the instructions given on the can.

    Removing a tight piston sleeve and connecting rod
    Tolerances between an engine's sleeve and crankcase are super-tight for a reason: any gap between the sleeve and crankcase can cause fuel and air to blow by the ports in the sleeve. When you want to remove the piston sleeve from the engine, this tight fit can cause problems. To minimize the risk of scratching either the piston or the sleeve itself, simply slide a few plastic zip-ties halfway into the exhaust port. Gently turn the flywheel back and forth, and as the piston pushes the zip-ties upward, the sleeve should be dislodged. Be sure your hands and fingers are completely clean, and then grasp the sleeve and pull it out completely.
    A tight connecting rod can also be a pain to remove, but luckily, there's an easy method. After you've removed the sleeve from the crankcase, place a few drops of oil on the brass connecting-rod bushing where it is mated with the crankshaft. Cut a short piece of dental floss, then loop it around the conrod. Now gently tug the floss to pull the conrod off the crankshaft, and then carefully pull the entire piston/conrod assembly out of the top of the engine.
  3. digdug72

    digdug72 Member

    wow sons, thanks bro, get on aim once in awhile so i can get some more track!! :), you still have that savage?
  4. yeah i still have it...
    got the buggy?
    my comp crashed and i only have 4 programs now
    i couldnt recover anything..but i just got aim today so i will be on more often again...
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