Clutch Stack One-Way

[Roger]

I managed to kill another one way bearing in my N7 clutch stack.  I switched to a Sullivan Dynatron and wand at Matts suggestion.  Today at the field I got one superb flight with the N7 and when I tried to start it for the second flight the bearing protested loudly and then spun freely.  The first start was flawless, the second one was utter disaster.  I am not sure what I am doing wrong, if anything. 

ROG

[Danny Dugger]

What engine w/ what fuel -- does the head need a shim to lower compression a little? Possibly clutch bell/start shaft to clutch/one-way alignment? Typically any starts after the first start of the day mine fires right up after the slightest bump of the starter. Is the starter shaft wobbling around badly when trying to start or is the one-way failing before the engine turns over?

[Roger]

This is the motor. http://www.ronlund.com/rcheli-prod/OSMG1980.html
I am running Coolpower 30%
Don't know about needing a head shim. None of the guys I fly with have mentioned it and they each have a big nitro.
Starter wand is brand new so there is no wobble in it.
I carefully align the clutch bell and start shaft.......getting pretty good at with all the practice I am getting.😁😁
I can't say whether it failed before or after the motor spun.

I have ordered new bearings.  They seem to be in very short supply.  Amain had three and I bought them all.  Amy was OOS and Heli  Direct had one.  Ron Lund was OOS as well.

ROG

[GAR]

From here... it sounds like a miss-alignment, canted shaft in one-way.
OR, the fan hub is spinning making you think it's a bad one-way.

I found getting the motor (105) shimmed off the motor mount so that everything else is aligned took some time to get the one-way to spin freely in setup.
I even had to install shims under the clutch so it would fully engage the clutch bell and one-way.

[Roger]

I am going to get a chance to check all the alignment again GAR. I am pretty carefull with it. I will be extra carefull this time. 

ROG

[Dan Minick]

Do you have the engine shimmed on the motor mounts? Most of the team guys I know are running them with OS engines. This could contribute to your problem, but I have run them both ways myself. It does like the shims better

[Roger]

Right now I do NOT have any shims between the motor and the frame.  Bearings are enroute from AMain.  I don't relish removing the motor to install shims. You can bet I will look at it real close. 

ROG

[Rctintin]

Don't remove the motor. Cut the one side of the hole away on the shim (on both holes) so that you can just loosen the mount bolts, and slide the shim into place, and nip the bolts back up.

I had to install shims on my first batch kit because the mesh was to tight between the pinion and main gear, not because of clutch alignment. Its been perfect ever since.

[Danny Dugger]

Shim to get main gear mesh right. If the main gear feels notchy when spinning and there's no wiggle in your main gear/pinion mesh it needs a little shimming. Just the slightest wiggle between them is all you need.

[Drew Robinson]

+1 on shimming 105, as well as +1 cutting slots to
Slide shims without pulling motor. If your that concerned about pulling motor, cutting shims works done it on people's Heli at events to fix alignment. Although the I typically instal them by pulling engine.

[Richard Rollins]

yup , I have YS 91 srx on my n7 need to shim as well.