question about conecting rod hitting

[whoanelly]

Hey guys , my engine(OShzr) keeps getting hot so i tore it down and i can see the connecting rod is hitting the bottom of the case ,not sure why but i can see its scratched up ..is something installed wrong cause ive taken all apart and cleaned to a tee thinking something might of been caught in there..
any help id appreciate..

[HiroboFreak]

Most likely the rear bearing needs replacing.

[whoanelly]

Originally Posted by HiroboFreak

Most likely the rear bearing needs replacing.

should i pull it out and check it out ? never pulled one out before ,ive got about 50 flights on the motor ,,just replaced piston ,sleeve and ring cause it got to hot..

[HiroboFreak]

Definitely replace it, even more so because you have freshened up the rest of the engine.
Replace the front bearing while you're at it.

[whoanelly]

Originally Posted by HiroboFreak

Definitely replace it, even more so because you have freshened up the rest of the engine.
Replace the front bearing while you're at it.

ya i just pulled it out and it does feel a little notchy,, u can see it got real hot as well..
i sure appreciate the help..with that bearing messed up though would it cause the rod to hit bottom of case ?
ty

[HiroboFreak]

Absolutely.

[whoanelly]

Originally Posted by HiroboFreak

Absolutely.

All ordered up ,,and thanks again for the help.

[ualdrivr]

Replace the rear bearing once a year regardless and the front, maybe every other year as a precaution

[BlackWatch88]

the back plate is what's holding the connecting rod and the crank sharft together, so its always scrached up

[HiroboFreak]

Originally Posted by BlackWatch88

the back plate is what's holding the connecting rod and the crank sharft together, so its always scrached up

He said "bottom of the case", not backplate.

[BlackWatch88]

Not sure where is bottom of the case other than the back plate....

[HiroboFreak]

The backplate attaches to the rear of the crankcase, the fan and clutch bolt to the crankshaft where it exits the front of the crankcase.
On the top of the crankcase you will find the cylinder head attached.

So the bottom of the case is.....

[BlackWatch88]

RIght, but if you mount it in a heli the front become the top and the bottom would be..

still its werid if its hitting where you think its hitting...you need to have a realllly messed up crank sharft or rear bearing to acheive that. never saw it...

[HiroboFreak]

Actually the front remains the front, it's just your perception that alters, hence the backplate is still the backplate, not the bottom plate.

The knocking noise you hear when the bearings are shagged is associated with the rod hitting the bottom of the case, as well as bearing rattle.
The engine also gets trickier to tune and can run hotter due to being under-compressed.

[Steve Graham]

When I tore mine down to have the bearing replaced by Buzz Butlers Magnum Fuels bushing I also found evidence that the bottom of the rod had been making contact with the case in the fashion you describe. I think a loose bearing is the most likely culprit. BTW, I think this bushing idea has potential. He warrants them for the life of the engine.

[whoanelly]

i replaced both bearings this weekend and she purrs like a kitten now, I think when i smoked the piston that it damaged bearing as well but were all good now flew yesterday like brand new. Thanks again guys.

[HiroboFreak]

Glad you got it sorted out.