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Rebuilding worn out engines?

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Old 05-11-2008, 07:14 PM
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Jester241
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Default Rebuilding worn out engines?

Say you buy an newer engine used off ebay or something and its basically worn out. I know its possible to rebuild them,but is it worth it and will it run as good as new for along time after a rebuild? If not worth it......why?

I love working on things and it seems like it would be fun to rebuild engines. I just wouldnt want to spend more money than the motor would be worth doing it. Please give me your thoughts on trying to make worn out engines good,reliable,long lasting engines once again.


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Old 05-11-2008, 07:52 PM
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PoormansACE
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Default RE: Rebuilding worn out engines?

Yes, you can rebuild most anything you can get parts for. I suggest you go to the tower&horizon sites to price some parts (say for an OSsaitottiger 1.28 speical!) and look what your getting into.

If the cost of repairs + the price of a used motor= %50-%60 of what the motor cost new, then to me its not worth the time.

but no matter what Its a HOBBY-HAVE FUN!!-DO WHAT YA DANNED WELL WANT TO AND DONT WORRY ABOUT THE PRICE UNTIL THE CREDIT CARD BILL COMES IN!!!
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Old 05-12-2008, 02:28 PM
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Default RE: Rebuilding worn out engines?

I don't give rebuilding my four strokes A second thought, it's well worth it for me but I have OS and YS engines so it's always worth it. Yes they last just as long. I'm rebuilding my OS 1.20 FS right now. Bearings from Boca about 40 bucks and the ring and gasket kit about 25 bucks. Add that up against A 300 plus dollar engine.
Some of the two strokes are worth it too.
One thing I have are the books on rebuilding these engines and they were well worth the price too over the years. Not much to A small engine but there are A lot of good tricks in these books.
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Old 05-12-2008, 04:50 PM
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Default RE: Rebuilding worn out engines?

Yes it is worth rebuilding worn engines. Only damaged engines may no be worth it, Bent cranks can do a lot of damage to the cases. Piston, cylinder and bearing replacement is common in race engines where high nitro content is used.

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Old 05-12-2008, 08:36 PM
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Default RE: Rebuilding worn out engines?

Yes you have to evaluate the price of a new engine against the cost of your repair.
I have repaired a number of engines since my begining in this hobby, and there is always a pleasure to perform those tasks.
I do prefer to repair my 4 stroke engine because of the value and because is cheaper to buy a couple of bearings and a ring than a whole brand new engine.
I have bought used engines on ebay thinking on rebuilding and merely as a hobby. But I always buy new engines for new planes.
As the Ghost said, bent cranks is like a big sign that you will never use that engine again, not worth the efforts but as he just said, piston, liner or cylinder and bearing replacement is common.

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Old 05-12-2008, 08:47 PM
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Default RE: Rebuilding worn out engines?

If you get stuck with a worn out engine off ebay, you've already lost money.

But any worn out engine can usually be brought back to almost new performance by swapping in a piston, cylinder, connecting rod, and bearings.

However, at today's prices for parts, if all those are worn out, the job probably won't be worth it. One of the most popular engines today is the OS46AX and just its piston/cylinder is priced by Tower at $70. The engine itself from Tower is $105.00. Whenever the piston/sleeve are worn enough they need replacing, you'd be advised to replace the bearings. And con-rods often will go sloppy just a bit after the piston/sleeve.

Your worn out ebay deal really might not have enough parts worth reusing. "Almost new" usually isn't.
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Old 05-13-2008, 07:21 AM
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Default RE: Rebuilding worn out engines?

Ringed engines are worth the cost of rebuilding. Sometimes the cost of a new piston and sleeve and new bearings are more than the cost of the engine. This would then only be worth the cost if it is an engine that is no longer made. Otherwise just buy a new engine. Keep the old engine for misc parts such as carb and backplate.
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