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HomeAircraftHelicopterGasser Model RC HelicoptersOther › Replacing Zenoah 270RC Piston for Newbie
01-29-2013 04:29 PM  5 years agoPost 1


somers point, nj

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Hey guys. I think I smoked my motor on my mongoose with a very lean run on the first cold day flying of the winter. It was bogging real heavily and I stupidly flew it like that not realizing what the bogging was from. Anyway I pulled apart the engine and it seems the piston has some rubbing damage on it.

So how hard is it to replace the piston? Do I just need a piston and the new gasket, do I need any special tools. I've never torn a motor apart so any advice you could give me before I put in an order to Dave's Motor would be appreciated. Thanks.


Helicopters don't fly, they beat the air into submission!

01-29-2013 05:12 PM  5 years agoPost 2

rrElite Veteran


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Well to do it right you do need a few specialty tool, (Flywheel Puller, Fan puller, Needlenose pliers, As far a difficalty, it's not hard, You will need to replace piston and ring, and if your head is scored too, you will need a new head, and all gaskets, Always take your time and make sure to mark piston front before you take it off the connecting rod, Most have a arrow, on top of the piston to let you know which is front, Your ring has to be put on correctly, there is a pin in the grove of the piston, that the opening of the ring needs to go againest the pin, if you don't do this, you will ruin piston and ring,, Good Luck, XGM/VGM

P.S. You only need the pullers, if you are going to split the cases,, If your crank and connecting rod is damaged. If you only pull the head, then all you need is the needle nose pliers,

John Crotts

01-29-2013 06:21 PM  5 years agoPost 3

rrKey Veteran

N. Tonawanda, NY

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Sometimes, just the piston and ring are damaged, other times the cylinder will be damaged too. It is possible, but rare, to damage the bottom end requiring the pullers so the crankcase can be split. It is pretty easy to pull the cylinder off so you can see the extent of the damage.

If running a stock engine, Daves Discount Motors has what you will need and it is not expensive. If it was a modified motor, the original builder will sell you just the parts to get it back together.

If you prefer, one of the engine builders can do it for you at a pretty reasonable price.

Google it, the boat builders have some good information on rebuilding the engines.

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