---------------------------------------------------------- TeamGrumman-List Digest Archive --- Total Messages Posted Tue 03/16/04: 4 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 05:42 AM - Voltage fluctuation and EGT temp differential (Weir, Douglas) 2. 09:57 AM - pre purchase inspections (kh) 3. 12:13 PM - Re: pre purchase inspections (flyv35b) 4. 05:17 PM - Re: Voltage fluctuation and EGT temp differential (FLYaDIVE@aol.com) ________________________________ Message 1 _____________________________________ Time: 05:42:57 AM PST US From: "Weir, Douglas" Subject: TeamGrumman-List: Voltage fluctuation and EGT temp differential --> TeamGrumman-List message posted by: "Weir, Douglas" I just got my plane back from annual from a non-Grumman shop (since it was there for painting), and have a couple of issues I wanted opinions on: 1) The voltage on my JPI 800 is now fluctuating between about 13.4v and 14v where previously it was very steady at about 13.8v. Could this indicate a weak battery? I just got the plane about 8 months ago, and I suspect the battery is over 2 years old, but there is no logbook entry. 2) The EGT temperature differential at times is near, and even over 200 degrees lower on the #2 cylinder than the highest cylinder (and all the others are pretty close). Prior to the annual the temperature differential was usually about 50 degrees, and only occasionally as high as 100 degrees. Some background: the #2 also had the lowest compression (68), and has at times fouled (cleared by leaning). Any thoughts on this? Thanks in advance, Doug Weir N414DJ *** Credit Lyonnais **************************************************** This e-mail contains confidential information or information belonging to Credit Lyonnais and is intended solely for the addressees. The unauthorized disclosure, use, dissemination or copying (either whole or partial) of this e-mail, or any information it contains, is prohibited. 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Credit Lyonnais in the Americas: Credit Lyonnais Bank New York Branch, Credit Lyonnais Americas Services Inc., Credit Lyonnais Rouse (USA) Ltd., and Credit Lyonnais Securities (USA) Inc. *** Credit Lyonnais **************************************************** ________________________________ Message 2 _____________________________________ Time: 09:57:31 AM PST US From: "kh" <13scrappy@comcast.net> Subject: TeamGrumman-List: pre purchase inspections --> TeamGrumman-List message posted by: "kh" <13scrappy@comcast.net> Does anyone have recommendations on someone for pre purchase inspections in MS (area code 662) Thanks kent ________________________________ Message 3 _____________________________________ Time: 12:13:13 PM PST US From: "flyv35b" Subject: Re: TeamGrumman-List: pre purchase inspections --> TeamGrumman-List message posted by: "flyv35b" Yeah, Bob Steward in Birmingham, AL ----- Original Message ----- From: "kh" <13scrappy@comcast.net> Subject: TeamGrumman-List: pre purchase inspections > --> TeamGrumman-List message posted by: "kh" <13scrappy@comcast.net> > > Does anyone have recommendations on someone for pre purchase inspections in MS (area code 662) Thanks > kent > > ________________________________ Message 4 _____________________________________ Time: 05:17:20 PM PST US From: FLYaDIVE@aol.com Subject: Re: TeamGrumman-List: Voltage fluctuation and EGT temp differential --> TeamGrumman-List message posted by: FLYaDIVE@aol.com In a message dated 3/16/04 8:43:49 AM Eastern Standard Time, Douglas.Weir@clamericas.com writes: > --> TeamGrumman-List message posted by: "Weir, Douglas" clamericas.com> > > I just got my plane back from annual from a non-Grumman shop (since it was > there for painting), and have a couple of issues I wanted opinions on: > > 1) The voltage on my JPI 800 is now fluctuating between about 13.4v and 14v > where previously it was very steady at about 13.8v. Could this indicate a > weak battery? I just got the plane about 8 months ago, and I suspect the > battery is over 2 years old, but there is no logbook entry. > > 2) The EGT temperature differential at times is near, and even over 200 > degrees lower on the #2 cylinder than the highest cylinder (and all the > others are pretty close). Prior to the annual the temperature differential > was usually about 50 degrees, and only occasionally as high as 100 degrees. > Some background: the #2 also had the lowest compression (68), and has at > times fouled (cleared by leaning). Any thoughts on this? > > Thanks in advance, > Doug Weir > N414DJ =================== Hi Doug: Grumman Vs Non Grumman shop does not matter in this case. I have been contacted by two people in the past week about the exact same problem you are experiencing in your item #1. Change in voltage readings. I have traced the problem to one common area:- POOR GROUNDS Now, what caused the poor grounds? That is harder to trace, explain, or guess at. I would take a WAG, especially if there was a removal of plane parts, that paint or corrosion got between a couple of mating parts. Or, when the plane was reassembled In a Hanger (warm area) and now being flown (colder area) a bit of expansion & contraction took place and now you have a resistant connection. Simple cure:- Add a few more grounds and clean up the ones you do have now (Battery +/-, Engine, Alternator, VR, and panel; just to name a few. And of course check the connections for the JPI. As for the EGT ... Again that points back to the JPI ... and I hate to say this, but have you checked the baffling and seals? How are the CHT's? If they are normal then it could be s simple thing like a bad probe or probe connection. Lots of things get moved around during a paint job and even more during an annual. Barry "Chop'd Liver"