Nasty tinny sound from 600N at idle - Still can't find the problem?

[rototiller]

It cant be a design flaw, yours is the only one I have heard to that. Sounds like your shoving a bolt in the fan when its idling. LOL.

The first vid you posted I could bearly hear the vibration but it did sound like the clutch was lose and vibrating on the bell. This is completley diffrent. More metal to metal sounding.

Good luck and let us know what you find out.
DK

[loiphin]

I doubt anything is loose. I have rebuilt that g*d damn clutch assembly so many times. All loctited properly as well. I had another look this evening while the heli was idling, and it is definitely coming from the clutch. I can see the clutch vibrating and sending out the corresponding sound. I think the engine is ever so slightly out of alignment, and is thus causing the bearings to go quicker and causing the bell to vibrate. But I dont know how to get it properly aligned. Maybe I need some new frames? Perhaps mine are not punched correctly. Hell, I have pretty much exhausted everything I can think of???

[loiphin]

Hi All,


I finally managed to fix the tinny sound problem that has been plaguing me for months. I had a new OS .50 Hyper as a spare and decided to swap the current OS .50 Max to see if it would make any difference. And what a difference! It is now running as smooth as butter. I did around 6 tanks today, slightly on the rich side to break in the engine and it really purrs.

So my theory is that the clutch bell was vibrating due to the crankshaft on the engine being slightly bent. I have never dropped the engine so I have no idea how this happened, assuming this is the true issue? I will buy a dial gauge and confirm if it is true. If this is the case, then no wonder my clutch bearings were only lasting a gallon or two!!


Here is a video of a happy Trex 600 Nitro Pro. Thanks to everyone for your tips and idea's.

http://www.youtube.com/watch?v=NxTv7uHgpOQ



Thanks again!


loiphin.

[rototiller]

AWSOME !! Glad you got it fixed.

Did you put a new liner in your clutch bell? Yours gets the head spining way faster than mine. Plus my motor wants to load up a lot more than yours. if I lean the low end out its hard to start. Havnt figured that part out yet.

Anyway, glad its fixed and now you can enjoy your bird.

DK

[AutumnSummers1]

put a little grease in the 1way it might have a little slop and causing it to make a very high pitch sound
if you are sure it is the cluch,why not replace it and 1way and starter shaft,that is what i would do

[AutumnSummers1]

cool glad you got it fixed

[loiphin]

rototiller - Yes, I am using the Raptor Heavy Duty Liner (PV0324). The clutch drags a little, but it engages quickly and smoothly when I rev it up. I think I prefer it to the original thinner clutch liner.

[DebianDog]

I KNEW it was the motor... crankshaft... so close.

[Kinger]

Tear down your original motor and replace the crank bearings. I can pretty much guarantee you that they are notchy. When I was flying 50's I had a metal on metal sound that happened at idle and it just got worse and worse and worse. Pulled the heli apart, checked the cluch, replaced the clutch, replaced the bell and checked a bunch of other things. Never found the problem. Then on some adviced from a more seasoned pilot, I tore apart the motor and found out the crank bearings were absolutely toast. Replaced them and all was well with the world again :)

[loiphin]

Kinger! I think you hit the nail on the head. I just took a look at the old motor and found that the rear bearing (nearest the piston) is shot. Really really rough. Looks like its a bit rusted from the fuel. The front bearing still feels nice and smooth. The oven is warming up as we speak to get this sucker out ;)

Thanks all!


loiphin.

[loiphin]

I should have listened to everyone in the beginning...... that I should check the motor bearings. But I didn't realize that the motor bearings could have such an impact on the vibration of the clutch. Because the rear bearing was so fubar, it must have caused a slight occilation in the crankshaft each time the engine fired and thus caused the clutch bell to vibrate, which in turn made the terrible noise.

LESSON LEARNT!

Loiphin :D :D

[rototiller]

Is that the 90 liner? Or a heavy duty 50?

DK

Edit: I think the back bearing gets lose and then allows the crank to move witch push's the clutch into the bell.

[loiphin]

Its the Heavy Duty 90 Liner Part # PV0324...


Here is a picture of the rear bearing... FUBAR!


http://farm3.static.flickr.com/2155/2143509575_ba71cb4560_b.jpg

[rototiller]

WOW, Yep, that bearing is toast.

Well, when you get the new bearing in then you will have a back up motor.

90 clutch liner, thanks
DK

[loiphin]

rototiller - I had a look at the crankshaft and it appears to have worn on one side where the rear bearing rests. Its only slight, but if I run a fingernail on the crankshaft I can feel a ridge where the bearing has worn the crankshaft. Does that mean a new crankshaft too?

loiphin.

[rototiller]

Ya, I would put a new crank in there. No sense in taking a chance on the old one. It could fit a little sloppy on the new bearings and then its a chain reaction that lead's you to the point you were yesterday.

I would drop a new ring in there also. There pretty cheap.

DK