Mailing List flyrotary@lancaironline.net Message #14989
From: Wendell Voto <jwvoto@itlnet.net>
Subject: Re: [FlyRotary] For Wendell Re: [FlyRotary] Re: Oil Pump Drive Key take 2
Date: Sat, 8 Jan 2005 13:39:24 -0600
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
 
----- Original Message -----
From: Leon
Sent: Saturday, January 08, 2005 9:36 AM
Subject: [FlyRotary] For Wendell Re: [FlyRotary] Re: Oil Pump Drive Key take 2
Thanks for the input Leon, will inspect per Ed's advice and decide if front cover needs to come off.
Wendell
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 -----
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
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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