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Old 04-23-2020, 10:28 PM
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Default HPI RS4 3 engine rebuild problems

I have neglected my RS4 3 for a long time, and the engine is frozen. So I took it apart to see what was up. There was some gunk in there, but not a lot. For the most part the inside of the engine was pretty clean.

But it still won't turn. I pulled the cylinder and piston out and that seems to be the problem. The piston is very tight and simply will not go above the halfway point, more or less. I managed to get it removed from the cylinder and there is no obvious issue. The sides of the piston and the cylinder walls are shiny and smooth, no gunk in there, nothing I can feel on either surface. But even after cleaning them up real good and wiping everything down, piston gets stuck halfway up. Only thing I can think of is the piston and/or cylinder is slightly warped. If so I can't feel it, and aside from sitting in my closet for a long time it was never abused. It was running fine the last time I played with it.

I looked for replacement parts and that's a laugh. Been out of production for quite some time of course.

The engine I have is the nitro star 15fe. The one with the purple heat sink. Does anyone have a suggestion on what else I can try to get it working? And if not, what options are there to replace the whole engine? It looks like the current nitro star T3.0 is the same type of engine, but I couldn't find anyone who had those in stock either.

Thanks for any advice you guys can give.