Zenoah shaft seals.

[Ian Inverarity]

Question for the gas guys out there:

I would like to run an extra bearing in the case at the collet end of the motor. Looking at the instructions that came with the engine, on the G260PU aircraft motor and the G231PUH helicopter engine a bearing is used in place of the shaft seal and this is a different bearing to the other two. Is this simpy a bearing with dual rubbing seals or is it something special? :huh:

Nitrocrazed racing: Not just nitro.

 

[nitrotoys]

I just had my 260 apart and i am 99.9% sure they are the same size, bearing surface, and seal surface. Cause on that end you have the bearing then a snap ring and then the seal. If you going to do something, Do Zerodrag seals.

Why would you want to put another bearing on the collet end?

Just asking, really dont know, but would like a reason as to what your thinking?

Tom

 

[Ian Inverarity]

Tom,

I am pretty sure the bearing used in the aircraft and heli engines is the same size, but it must be different to work as a seal.

I would like an extra bearing to reduce the crank runout that sometimes happens. Another bearing should hold the crank straight.

Ian.

 

[DaveMarles]

On an G23 aircraft engine I have here that extra bearing looks like a 6001 2RS rubber sealed bearing. Doesnt look like the bearing has special seals but they may be teflon. The zenoah bearing is very little money.

Dave

 

[Ian Inverarity]

Dave,

Thanks for the tip, if they are cheap I will try to track down an original!

Ian.

 

[boaterbill]

The no drag seals work great, there are two models out there, depends opon how much you want to spend. Work good for me.

Bill

 

[speed3172]

Nitrocrazed,

Here's the scoop on that extra sealed bearing....

The sealed bearing from the airplane/heli engine will fit....but the rubber seal in the bearing doesn't do as well a job of sealing as the actual crank seal does. I've heard that eventually, the motor will start to leak crankcase pressure out the bearing and you'll start getting mysterious lean runs. I had some issues with a QD 25 that were corrected by using seals again instead of sealed bearings.

Another noteworthy point: I've heard (read as I don't know for sure) that double bearings aren't needed at the collet end of the motor...only on the flywheel side. You may want to research this further on Jim's RC Boatdock....there are all sorts of petrol sniffers over there and many may be able to pass on their experiances as well.

- Steve

 

[Mike T.]

The plane engine bearing will work. Marine Specialties has the Zenoah item. But it won't stop the crank "runout" problem, more correctly crank misalignment. The crank is assembled from two crank throw (crank cheeks) and a crank pin, pressed together. When the engine is hydro-locked or if you put too much force on the shaft while using a piston stop, the crank throw can turn on the crankpin, and the crank will wobble. You can see the runout very easily on the flywheel. The fix is to take the crank out an put it on a lathe (supported by the center on the ends) with a dial gauge and whack the crank cheeks with a hammer in just the right place with just the right amount of force to put it back in line. Then stop using the piston stop and dont flip the boat anymore.

 

[Ian Inverarity]

Mike,

I have straightened (re-aligned) a few cranks in a lathe.

What I actually want to do is put 4 bearings on the crank. With 4 bearings the crank pin doesn't need to be a press fit and will still stay in alignment. Not that I am going to change the crank pin fit!

I try to minimise the boat flips too! But things dont always go to plan!! B)

Ian.

 

[Mike G]

:blink: Ian not flip a boat????? :lol: :lol: :lol: :lol:

Yeah like that will ever happen

If he is not going flat out he's got engine troubles!

 

[Ian Inverarity]

Mike,

You're just thinking of the time I lost control of my brand new 90 rigger coming out of a turn and headed at the bank with the front sponsons in the air at about 75mph and I didn't back off the throttle till about 20 foot out...

Nitrocrazed racing: Win or Bust!!

 

[Danny Bull]

Hi Guys, I don,t believe that there's any advantage to using 2 bearings in the front housing of a Zenoah engine. Dunking it at speed with the throttel wide open is the biggest killer of gas engines. To my knowlege, the 6001-2RS is only a semi-sealed bearing, the seal is only good for keeping out rocks and tree branches...... :lol: The 6001 ZZ is a fully sealed bearing that can be used as a replacement for the original bearing if a seal is not used or if using a second bearing.

Hope this helps.

Cheers, Danny.

 

[DaveMarles]

6001 ZZ is a metal shielded bearing. Doesn't seal at all.

 

[Danny Bull]

Now that I've had time to check as there are no bearing shops open here at 5 in the morning, the number I was looking for is 6001 LLU not 6001 ZZ. Thanks for pointing that out Dave.

Cheers, Danny.