What you are hearing is one of 3 things or possibly all 3 at the same time,,, lower piston connecting rod bearing play, upper piston connecting rod bearing play or piston pin play.

Its a normal sound that you are hearing

All bearings and piston pins have some play in them, some more than other, some less than.

Tell tale signs of bad bearings,,, the front bearing seal ruptures and lets the grease out and poor engine performance. All other bearings inside the engine just before they let go will produce a silvery grey/black residue out the mufflers onto the plane and with a louder than normal KLANKING sound.

A complete 3W-170 redhead rebuild after an inner bearing failure in flight is spendy

Originally Posted by Bill Vargas

What you are hearing is one of 3 things or possibly all 3 at the same time,,, lower piston connecting rod bearing play, upper piston connecting rod bearing play or piston pin play.

Its a normal sound that you are hearing

All bearings and piston pins have some play in them, some more than other, some less than.

Tell tale signs of bad bearings,,, the front bearing seal ruptures and lets the grease out and poor engine performance. All other bearings inside the engine just before they let go will produce a silvery grey/black residue out the mufflers onto the plane and with a louder than normal KLANKING sound.

A complete 3W-170 redhead rebuild after an inner bearing failure in flight is spendy

Hehe ok. So the sound is normal then. I’m pretty sure I’m imagining new sounds, since I don’t have a clue why the *** woodkey (maybe it’s actually made of wood/balsa!) is shredding. In the beginning it was obviously cuz of the bad ignition,/backfire but now it’s a new ignition and the engine seams to run smooth.

I think the key shredded just as the engine started (and it didn’t backfired)

So let’s say the motor is “fine“.

Can it be:

1, Maybe I have not used enough/ proper locktite on the hub? (I have never applied locktite on the centre screw, is that really necessary?)

2, maybe my measurement of the 28 degree was not 100% so the timing has shifted during mounting the sensor with the round metal screw thing (don’t now what is called in English ( It’s Called “slangeklemme” in Norwegian).

I’m currently running a 6V battery. Should be fine.

In your picture here did you tap the Woodruff Key down into the slot before you installed the prop hub?


Also, per Gerhard instructions to me a long time ago when installing a new prop hub, did you happen to heat up the new prop hub with a heat gun a little bit prior to installing it?

Originally Posted by Bill Vargas

In your picture here did you tap the Woodruff Key down into the slot before you installed the prop hub?


Also, per Gerhard instructions to me a long time ago when installing a new prop hub, did you happen to heat up the new prop hub with a heat gun a little bit prior to installing it?

Hmm interesting suggestions. No, I have not heated the Hub or tap the key down. So the key should be tapped down a bit? Ok shall the hub be heated so it gets as warm as when I remove the Hub? I guess I must use a special locktite that can handle that heat, but that also can be removed when (or hopefully not!) the thing shreds the 4’th time.

Dont get too disheartened.......
Engine issues plague many of us at some point in time , frustrating .......oh yes , in particular when nothing is working out
It works out eventually

You might be ok on the key not being tap down.Only reason I say that is because ,if the key push out when installing hub.It would be between the bearing face and hub and not allowing the hub to seat.Unless it just fell out when installing the hub.

Originally Posted by Knifedive

Hmm interesting suggestions. No, I have not heated the Hub or tap the key down. So the key should be tapped down a bit? Ok shall the hub be heated so it gets as warm as when I remove the Hub? I guess I must use a special locktite that can handle that heat, but that also can be removed when (or hopefully not!) the thing shreds the 4’th time.

make sure the Key is Seated in the grove and then when installing the key ensure that it stays put as your sliding on the prop hub to make sure it does not fall out the back (at the bearing face) as closet said.

Then you should be good.

Have you removed the hub to see the condition or presents of the key?

Originally Posted by closetguy

You might be ok on the key not being tap down.Only reason I say that is because ,if the key push out when installing hub.It would be between the bearing face and hub and not allowing the hub to seat.Unless it just fell out when installing the hub.

Originally Posted by The Hodge

make sure the Key is Seated in the grove and then when installing the key ensure that it stays put as your sliding on the prop hub to make sure it does not fall out the back (at the bearing face) as closet said.

Then you should be good.

Have you removed the hub to see the condition or presents of the key?

I will check it, try to install it once again. The remaining parts of the shredded keys look like they were shredded about 50% of the key.

I also asked 3W if there is a moment on the centre screw, but they say it’s no moment on that screw, just tight it good.

I’m looking at my “new” hub and can see that is has become slightly mis shape / uneven in the key track, This actually happened in the first attempt with the old ignition. Can that have something to do with it? I believe it’s sitting tight even with that little shape.

My old Hub Actually looks better, but the magnets are sitting with a longer distance to each other, I don’t know if that is important. Can of course move the sensor according to that magnet / hub as well.

It looks like with the new hub when the key has sheared it has rolled the edge and and you can see plenty on metal transfer/scoring from the key material.

if I recall the magnet spacing just a change in engine series/update and your Rxecel unit will only use one of the magnets, There is a N and S one, Only one first the Rcexel unit.

It would be worth while to pull off the cylinders and see when the piston are at TDC that the crank does not have a twist in it, Ie make sure the counter weight and journal's on the shaft are even/Level.

Based on the photo above the shaft needs cleaned or replaced. Can't tell if the shaft is worn or that aluminum has transfer to the shaft. At any rate the taper must fully engage to lock the hub in place.
If it where mine I would clean the shaft and hub up, heat the hub and tighten the center nut a high torque.

Looking at your new hub I don’t think it will ever work. Once it spun the tapper is now distorted. The key way does nothing from keeping the hub on the crank or slipping. The only thing the key way does is allow you to take the hub off and then put back on and keep the same timing.
I’ve been to the 3w factory. I have also installed several hubs. Best method is to have both tappers nice and clean. Warm up the hub with a heat gun, apply a thin coat of green loctite made for bearing races onto the crankshaft tapper. Then slide the hub onto the shaft, tighten the hub bolt while holding the hub with a pair of channel locks wrapped with a towel. Once tight I usually take a piece of solid rod and strike the handle of the ratchet to give a shock for that last bit of tightness.

The factory and dealers have the proper tools to hold the hub and don’t have to rig something up. I’m just giving you the home garage method that has always worked for me.

Having changed a couple of 3W hubs here as well,,, an old C/F prop was sacrificed just for this purpose. Use prop bolts and bolt it up to the hub while its still warm then hold it with some channel lock plyers,,, install hub nut,,, done. The threads on the end of the crank shaft is M8 x 1

That is one thing that I haven't done is to heat the hub up for easier removal.I was always afraid of over heating the magnets,but I guess it can be done. Probably best not to run it till you figure out if the crank has slip.Your hubs look scary enough.

If your worried about heating the hub and heat damaging the magnets, purchase the new Hub with holes drilled for the magnets and a set of new magnets then install magnets last. Magnets can also be replaced on the old hub as needed,,, the G man does sell them separately.