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Leon & Ken Powell, about staking the key in the shaft: I understand
staking, just wonder where your punch - about midway from each end of key,
i.e., on side of key - just put a center punch there and tap lightly on each
side to put slight hold on key (after putting a bit of Loctite in the slot
before the key is placed, like Ken Powell said)?
If the above is correct, then I assume the slight "blip" of the punch won't
interfere with the sprocket being slid on - must be enough chamfering or
some such clearance on the sprocket to not get caught on the staking spots.
David Carter
Nederland, Texas
----- Original Message ----- From: "Leon" <peon@pacific.net.au>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Sent: Saturday, January 08, 2005 9:36 AM
Subject: [FlyRotary] For Wendell Re: [FlyRotary] Re: Oil Pump Drive Key take
2
Wendell,
Nah, the inspection is done during assembly. If you wasnt to check it on
an assembled engine, basically, the frotn cover has to come off, and the
nut and lock washer removed. That's why it's always smart to double check
DURING assembly!
During assembly, the whole pump is already bolted on the engine. The oil
pump DRIVEN sprocket together with the crank DRIVE sprocket & chain are
slipped on the two shafts. The trick is not to dislodge the Woodruff key
from the keyway on the pump shaft. As I said below, I normally LIGHTLY
stake the keyway in the pump shaft. Just a GENTLE tap with the blade of a
small chisel or screwdriver is usually enough. Then the key itself can't
easily slip. Trial fit the oil pump sprocket before you attempt it with the
chain and the E-Shaft sprocket.
You need to look down the keyway of the sprocket to make sure you can see
the key and line it up with the keyway anyway. With a bit of juggling and
jiggling, it will all fall into place. If it's not correctly installed,
it is obvious. The key should be within 4 mm of the end of the sprocket. I
don't know how else to describe it. With the key correctly installed, I
usually then line up the drive sprocket and counterweight, then fit the
square E-Shaft key. Then I fit the oil pump lock washer & nut, tighten the
nut, and fold over the lock washer tab (MOST important!!)..
Hope this clarifies the situation,
Leon
----- Original Message ----- From: Wendell Voto
To: Rotary motors in aircraft
Sent: Saturday, January 08, 2005 11:22 AM
Subject: [FlyRotary] Re: Oil Pump Drive Key was Re: [FlyRotary] Re: Some
things to check
----- Original Message ----- From: Leon
To: Rotary motors in aircraft
Sent: Friday, January 07, 2005 2:46 PM
Subject: [FlyRotary] Oil Pump Drive Key was Re: [FlyRotary] Re: Some
things to check
Wendell,
Ed Anderson had a problem where the oil pump Wooodruff key wasn't in the
keyway. The drive was just taken by the friction of the tensioned nut.
Worked for a while. Sooner or later, the sprocket will slip on the shoulder
of the pump shaft. The symptom is intermittent loss of oil pressure, which
gets worse as the sprocket wears on the shaft shoulder.
So, as I said in the post below, always make sure that the key is
actually in the keyway before fitting to nut & lockwasher. The key itself
is very tiny, and it requires a bit of juggling to get it in the keyway in
the sprocket. I normally gently stake the keyway in the shaft so that the
key can't slip out.
Hope this makes sense!
Leon
Thanks Leon, can proper installation be checked by inspection or do
you have to remove the pump and start over?
Wendell
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