Return-Path: Received: from email2k3.itlnet.net ([64.19.112.12] verified) by logan.com (CommuniGate Pro SMTP 4.2.5) with ESMTP id 595983 for flyrotary@lancaironline.net; Sat, 08 Jan 2005 14:30:30 -0500 Received-SPF: none receiver=logan.com; client-ip=64.19.112.12; envelope-from=jwvoto@itlnet.net Received: from rav.itlnet.net (unverified [192.168.10.149]) by itlnet.net (Rockliffe SMTPRA 6.1.16) with SMTP id for ; Sat, 8 Jan 2005 13:29:57 -0600 Received: from JWVOTO (unverified [64.19.116.38]) by itlnet.net (Rockliffe SMTPRA 6.1.16) with SMTP id for ; Sat, 8 Jan 2005 13:29:55 -0600 Message-ID: <003f01c4f5b8$c4b377a0$26741340@JWVOTO> From: "Wendell Voto" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: Oil Pump Drive Key was Re: [FlyRotary] Re: Some things to check Date: Sat, 8 Jan 2005 13:21:15 -0600 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0026_01C4F584.EE7D6520" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 5.50.4133.2400 X-MimeOLE: Produced By Microsoft MimeOLE V5.50.4133.2400 This is a multi-part message in MIME format. ------=_NextPart_000_0026_01C4F584.EE7D6520 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Thanks Ed for the info. Will drop the oil pan and check this out. Wendell Wendel, One suggestion I have is to bend a paper clip so that an leg = is sticking straight out (or any other such) then insert it into the = keyway. I forget now but I think it should not go in much more than = 1/4" IF the key is present, I'll check on a pump I have in the shop = tomorrow. If you find the paper clip going in more than 1/2" (I'll = check tomorrow) you key is likely missing. Further amplification on what Leon said about the key - it is easier = than you may think to put the key in the keyway and slide the sprocket = on the shaft and push the keyway out. Normally when that happens you = hear the "ping" as the metal key hits the floor. But in this case, It = appears that when I push the key out the back side as I slid on the = sprocket, I actually clamped the key between the sprocket and the pump = housing. The reason I am confident that is what happened is the mark of = the key was impressed into the soft aluminum housing. The first spin = of the sprocket then threw the key into the bottom of the pan. Fortunately I had torqued the nut to the books specs (which many think = is a bit high for that small a nut) and flew with it for 10 hours. One = evening when I was at Tracy's we were looking into the throttle bodies = and I had push my throttle in all the way to open the butterfly. Forgot = to close it. Next more was cool and when I started the engine it = immediately (wide open throttle ) fired and zoomed to 5000 rpm with cold = 50 weight oil. That broke the clamp of the nut and it started to turn = the sprocket faster than the shaft and actually wore a small circular = place around the sprocket shaft as it rubbed against the shoulder of the = shaft. Tracy, Finn and I were going flying. A very lite breeze from the = north, but Tracy and Finn elected to take off to the south. Unless an = unusual situation exists, I always take off into the wind, so I elected = to taxi to the south end for my up wind take off. One the way taxing I = noticed that my oil pressure was only reading 20 psi when it normally = reads 30 - 50 psi.=20 I tried telling myself it must be a bad sensor or gauge and nothing = was really wrong, but I just couldn't ignore that anomaly and decided to = abort the take off and taxied back to the hangar. Fortunate decision as = I doubt the oil pressure would have stayed as high as 20 psi had I = decided to fly. After much "try this, try that" it finally because apparent the = engine would have to come off. Tracy's is the best place in the world (other than perhaps your home = hangar) to have a problem. He had a replacement oil pump and helped me = get it all back together using his hangar for my repair. A great place = to have to spend time down for repair. FWIW. Ed Anderson ----- Original Message -----=20 From: Wendell Voto=20 To: Rotary motors in aircraft=20 Sent: Friday, January 07, 2005 7:22 PM Subject: [FlyRotary] Re: Oil Pump Drive Key was Re: [FlyRotary] Re: = Some things to check ----- Original Message -----=20 From: Leon=20 To: Rotary motors in aircraft=20 Sent: Friday, January 07, 2005 2:46 PM Subject: [FlyRotary] Oil Pump Drive Key was Re: [FlyRotary] Re: = Some things to check=20 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 ------=_NextPart_000_0026_01C4F584.EE7D6520 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Thanks Ed for the info. Will drop the oil pan = and check=20 this out.
Wendell

Wendel,  One suggestion I have = is to bend a=20 paper clip so that an leg is sticking straight out (or any other such) = then=20 insert it into the keyway.  I forget now but I think it should = not go in=20 much more than 1/4" IF the key is present, I'll check on a pump I have = in the=20 shop tomorrow.  If you find the paper clip going in more than = 1/2" (I'll=20 check tomorrow) you key is likely missing.
 
Further amplification on what Leon = said about the=20 key - it is easier than you may think to put the key in the keyway and = slide=20 the sprocket on the shaft and push the keyway out. Normally when = that=20 happens you hear the "ping" as the metal key hits the floor.  But = in this=20 case, It appears that when I push the key out the back side as I = slid on=20 the sprocket, I actually clamped the key between the sprocket and the = pump=20 housing.  The reason I am confident that is what happened is the = mark of=20 the  key was impressed into the soft aluminum housing.  The = first=20 spin of the sprocket then threw the key into the bottom of the=20 pan.
 
Fortunately I had torqued the nut to = the books=20 specs (which many think is a bit high for that small a nut) and flew = with it=20 for 10 hours.  One evening when I was at Tracy's we were looking = into the=20 throttle bodies and I had push my throttle in all the way to open the=20 butterfly.  Forgot to close it.  Next more was cool and when = I=20 started the engine it immediately (wide open throttle ) fired and = zoomed to=20 5000 rpm with cold 50 weight oil.  That broke the clamp of the = nut and it=20 started to turn the sprocket faster than the shaft and actually wore a = small=20 circular place around the sprocket shaft as it rubbed against the = shoulder of=20 the shaft.
 
Tracy, Finn and I were going = flying.  A very=20 lite breeze from the north, but Tracy and Finn elected to take off to = the=20 south.  Unless an unusual situation exists, I always take off = into the=20 wind, so I elected to taxi to the south end for my up wind take = off.  One=20 the way taxing I noticed that my oil pressure was only reading 20 psi = when it=20 normally reads 30 - 50 psi.
I tried telling myself it must be a = bad sensor or=20 gauge and nothing was really wrong, but I just couldn't ignore that = anomaly=20 and decided to abort the take off and taxied back to the hangar.  = Fortunate decision as I doubt the oil pressure would have stayed as = high as 20=20 psi had I decided to fly.
 
  After much "try this, try = that" it finally=20 because apparent the engine would have to come off.
 
Tracy's is the best place in the = world (other=20 than perhaps your home hangar) to have a problem.  He had a = replacement=20 oil pump and helped me get it all back together using his hangar for = my=20 repair.  A great place to have to spend time down for=20 repair.
 
FWIW.
 
Ed Anderson
 
 
 
 
 
----- Original Message -----
From:=20 Wendell Voto=20
To: Rotary motors in = aircraft=20
Sent: Friday, January 07, = 2005 7:22=20 PM
Subject: [FlyRotary] Re: Oil = Pump Drive=20 Key was Re: [FlyRotary] Re: Some things to check

 
----- Original Message ----- =
From:=20 Leon=20
To: Rotary motors in = aircraft=20
Sent: Friday, January 07, = 2005 2:46=20 PM
Subject: [FlyRotary] Oil = Pump Drive=20 Key was Re: [FlyRotary] Re: Some things to check

Wendell,
 
Ed Anderson had a problem where = the oil pump=20 Wooodruff key wasn't in the keyway.  The drive was just taken = by the=20 friction of the tensioned nut. Worked for a = while. Sooner or=20 later,  the sprocket will slip on the shoulder of the pump=20 shaft.  The symptom is intermittent loss of oil = pressure,  which=20 gets worse as the sprocket wears on the shaft = shoulder.
 
So,  as I said in the post = below, =20 always make sure that the key is actually in the keyway before = fitting to=20 nut & lockwasher.  The key itself is very tiny,  and = it=20 requires a bit of juggling to get it in the keyway in the = sprocket. =20 I normally gently stake the keyway in the shaft so that the key = can't slip=20 out.
 
Hope this makes = sense!
 
Leon
Thanks Leon, can proper = installation be=20 checked by inspection or do you have to remove the pump and = start=20 over?
Wendell
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