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04-25-2020, 03:12 PM
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Join Date: Jan 2015
Location: Oklahoma City, OK
Posts: 534
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Has anyone else experienced this?
Finishing up my annual condition inspection and the A&P and I were checking connections and nuts on FWF. Everything was tight and secure except when we got to the fuel injector throttle body. Only one of the four nuts securing it to the engine was tight. Two were so loose you could spin them with your fingers and one was totally gone. The engine still ran smoothly.
Replaced all star lock washers, replaced the missing nut and tightened all to torque. We then added four nylon end nuts on top of the existing nuts and secured them - there was just enough room on the studs.
My A&P said this was the first time he?s ever seen nuts loosened like this - especially if no one?s worked on the item. He distinctly remembers checking the throttle body last year and every thing appeared secure then.
Our question: My engine is the Superior XP IO-360 B1AA2, has anyone else found they?ve had to tighten these nuts due to them becoming loose? This could have really ruined my day later this year if not discovered!
__________________
Jim Harris, ATP, T38, EC/KC-135A/E/R, 2008 RV7A, 2nd owner, N523RM (2015)
Superior XPIO-360, Hartzel CS prop, Aerotronics panel with Dual GRT Horizon WS, EIS, Garmin 340, 335 w/WAAS gps, Dual 430s (non-WAAS), TruTrak 385 A/P with auto-level, Electric trim, Tosten 6 button Military Grips, FlightBox wired to WS, Dynon D10A w/battery backup, 406 MHz ELT. Custom Interior, New TS Flightline hoses, Great POH!
Retired - Living the dream - going broke!
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04-25-2020, 03:21 PM
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Join Date: Feb 2005
Location: Indiana
Posts: 173
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Jim
I have the same exact engine on my RV7. I have found mine tight at all times. I have never found them to be loose.
Stay safe & good luck.
Darren Kerns
RV7 N599DT
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04-25-2020, 03:39 PM
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Join Date: Jun 2005
Location: Georgetown, TX
Posts: 331
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Nylon end nuts?
It's not a good idea to use AN364, AN365 nuts in hi temp environments (i.e. firewall forward). The "nylon" will degrade quickly and fail, allowing the nut to loosen, turn, fall off...
__________________
Brian Decker
Retired Firmware Guy and Airplane Builder
2020 RV-14 QB -- Under construction - Tailcone & Empennage Complete.
2018 RV-7 QB -- Built, Flying
2007 RV-7 QB -- Built, Drowned, Resurrected and flying
1998 RV-8 QB -- Started, Sold
1986 Mooney 205SE
1980 Mooney 231
Aided and abetted building a number of other RV's.
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04-25-2020, 06:25 PM
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Join Date: Jan 2015
Location: Oklahoma City, OK
Posts: 534
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Quote:
Originally Posted by bjdecker
Nylon end nuts?
It's not a good idea to use AN364, AN365 nuts in hi temp environments (i.e. firewall forward). The "nylon" will degrade quickly and fail, allowing the nut to loosen, turn, fall off...
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The A&P and I discussed this and felt like where these were located shouldn?t be a problem for the nuts, besides these are ?locking nuts? just helping to secure the primary nuts. Certainly better than no locking nuts at all given the recent discovery.
__________________
Jim Harris, ATP, T38, EC/KC-135A/E/R, 2008 RV7A, 2nd owner, N523RM (2015)
Superior XPIO-360, Hartzel CS prop, Aerotronics panel with Dual GRT Horizon WS, EIS, Garmin 340, 335 w/WAAS gps, Dual 430s (non-WAAS), TruTrak 385 A/P with auto-level, Electric trim, Tosten 6 button Military Grips, FlightBox wired to WS, Dynon D10A w/battery backup, 406 MHz ELT. Custom Interior, New TS Flightline hoses, Great POH!
Retired - Living the dream - going broke!
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04-25-2020, 06:30 PM
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Join Date: Jun 2012
Location: Frederick, MD
Posts: 821
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Quote:
Originally Posted by Tankerpilot75
Finishing up my annual condition inspection and the A&P and I were checking connections and nuts on FWF. Everything was tight and secure except when we got to the fuel injector throttle body. Only one of the four nuts securing it to the engine was tight. Two were so loose you could spin them with your fingers and one was totally gone. The engine still ran smoothly.
Replaced all star lock washers, replaced the missing nut and tightened all to torque. We then added four nylon end nuts on top of the existing nuts and secured them - there was just enough room on the studs.
My A&P said this was the first time he?s ever seen nuts loosened like this - especially if no one?s worked on the item. He distinctly remembers checking the throttle body last year and every thing appeared secure then.
Our question: My engine is the Superior XP IO-360 B1AA2, has anyone else found they?ve had to tighten these nuts due to them becoming loose? This could have really ruined my day later this year if not discovered!
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Nuts were not properly torqued, or something in the stack up ( servo/ brackets/ gaskets) was not right.
__________________
Dan Morris
Frederick, MD
PA28-140
Hph 304CZ
RV6 built and sold
N199EC RV6A flying
Learn the facts. "Democracy dies in darkness"
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04-26-2020, 04:32 PM
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Join Date: Jul 2007
Location: Litchfield Park, AZ
Posts: 1,019
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A quote from Vic S. on this exact topic.
"While doing a prebuy on Friday on an RV-8 I noticed a nut missing from the aft fuel servo mounting stud. This is not the first one of these I have discovered missing on an airplane. I know standard practice has been to use a nut, a lock washer, and washer, but for many years now I have been using AN363 all metal stop nuts with a washer in these locations and I have never seen one come loose. You might consider it on your airplane."
Here's the thread: http://www.vansairforce.com/communit...ttle+body+nuts
__________________
Carlos in Arizona
EAA Chapter 538 www.chapters.eaa.org/eaa538
Wittman Tailwind W8 N53CH (built & sold)
Pazmany PL-1 N2029 (bought & sold)
RV7 - N537TC (reserved & building)
Emp, Wings & Fuse done - working on FWF
"The air is an extremely dangerous, jealous and exacting mistress. Once under the spell most lovers are faithful to the end, which is not always old age." - Winston Churchill
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04-26-2020, 04:42 PM
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Join Date: Jul 2007
Location: Delta, CO/Atlin, BC
Posts: 2,391
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I agree with Vic/Carlos, if you want to be sure, use metal stop nuts.
__________________
Greg Arehart
RV-9B (Big tires) Tipup @AJZ or CYSQ
N 7965A
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04-26-2020, 05:57 PM
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Join Date: Sep 2011
Location: Melbourne Australia
Posts: 51
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Yes indeed
Whilst I was completing my build another builder at our airfield had this same problem after 25hrs. Only one tight nut! The servo was about to fall off.
😳😳😳😳
I have added different types of metal locknuts. On top of the supplied ones.
one type is thin nut due lack of available threads.
Dont ask for part numbers as the docs are not handy.
__________________
Rob Rickards
Melbourne Australia
RV7 VH-RRA flying Sept 2017
Sept 2019 180 hours
=VAF=. 2019 Donor
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04-26-2020, 07:25 PM
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Join Date: Jun 2007
Location: new iberia la
Posts: 768
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Loose hardware.
Metal locknuts are not a bad idea. The probability of the correct hardware and gaskets coming loose after being properly torqued is incredibly small. I?ve seen a couple cases where the wrong gasket (thicker & softer) was installed and even though properly torqued, over a week or two would compress and unload the lock washers and allow whatever component to become loose. Extremely important that the mags have the right gaskets. My experience is that fuel servos are not unusually prone to coming loose. Always a great idea at every condition inspection or 100 hrs of operation to check the torque on every fastener you can reach.
Don Broussard A&P/IA/ATP
RV9 Rebuild in Progress
57 Pacer
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04-26-2020, 09:01 PM
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Join Date: Mar 2009
Location: Arvada, CO
Posts: 118
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Same setup on my RV7. No issues after 300 hours. I recommend torque seal here, to make verification easy.
Good luck and keep looking closely at everything...Jim
__________________
Jimzims
2015 RV7 I0-360 FP
Dues gladly paid, 2020
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