Bubblehead
Well Known Member
I have been researching oil leaks because I have been fighting one on my engine for a couple of months. I came across several accident reports for airplanes with "D" suffix engines that experienced loss of power, sometimes engine overspeed, and often complete destruction of the engine due to loss of oil between the prop governor and the governor mounting pad. This pertains to rear mounted governors.
My engine is a O-360-A1F6D converted to fuel injection so this concerned me. The problem arises because engines with dual magnetos need a spacer plate with gaskets on each side on the prop governor or the governor shaft will bottom out and hold the governor out just enough to allow for an oil leak. Sometimes minor, sometimes catastrophic.
If you have a dual mag engine make sure you have this plate and the 2 correct gaskets installed.
Confusion happens over the right installation parts because Hartzell's instructions don't show it, they only say these are general instructions and check your airframe and powerplant manuals. Cessna's orginal manuals for the Cardinal RG, where my engine came from, don't show the spacer plate but Cessna put out an update that has apparently not been noticed by a lot of A&P/AIs. The Lycoming parts manual for my engine does show the plate but does not show the governor in the same illustration so it does not tell you to add the second gasket. That is why 1438A (below) is so important. In 1438A it shows the plate and two-gasket arrangement but with the close off plate not the governor. The 2nd gasket in that diagram has to be replaced with a MS9144-01 gasket. The Hartzell number for that gasket is B-1104, also available from Tempest.
The correct lineup in my case is a Lycoming 72053 gasket against the mounting, then a LW-12347 plate, then a MS9144-01 or B-1104 gasket against the governor. Here is a diagram from the Mooney document listed below that shows it best.
Here are references starting with the primary sources, Lycoming, the FAA and Hartzell.
Lycoming Service Instruction 1438A
http://www.lycoming.com/content/service-instruction-no-1438a
FAA Special Airworthiness Instruction NE-06-08
http://www.cessna.org/documents/public_info/saib/saib-ne-06-08.pdf
Hartzell Service letter HC-SL-61-277
http://hartzellprop.com/wp-content/uploads/HC-SL-61-277-R04-W.pdf
For more background information check these out. The Mooney document has the best diagram of what is needed.
http://www.ntsb.gov/about/employment/_layouts/ntsb.aviation/brief2.aspx?ev_id=20070703X00871&ntsbno=SEA07LA172&akey=1
http://www.mooney.com/en/si/M20-120.pdf
http://www.cardinalflyers.com/tech/info/govplate.php
http://www.fomento.gob.es/nr/rdonlyres/530301f2-9eed-4562-afc4-d0c27e26c2ce/105659/2008_023_in_eng.pdf
My engine is a O-360-A1F6D converted to fuel injection so this concerned me. The problem arises because engines with dual magnetos need a spacer plate with gaskets on each side on the prop governor or the governor shaft will bottom out and hold the governor out just enough to allow for an oil leak. Sometimes minor, sometimes catastrophic.
If you have a dual mag engine make sure you have this plate and the 2 correct gaskets installed.
Confusion happens over the right installation parts because Hartzell's instructions don't show it, they only say these are general instructions and check your airframe and powerplant manuals. Cessna's orginal manuals for the Cardinal RG, where my engine came from, don't show the spacer plate but Cessna put out an update that has apparently not been noticed by a lot of A&P/AIs. The Lycoming parts manual for my engine does show the plate but does not show the governor in the same illustration so it does not tell you to add the second gasket. That is why 1438A (below) is so important. In 1438A it shows the plate and two-gasket arrangement but with the close off plate not the governor. The 2nd gasket in that diagram has to be replaced with a MS9144-01 gasket. The Hartzell number for that gasket is B-1104, also available from Tempest.
The correct lineup in my case is a Lycoming 72053 gasket against the mounting, then a LW-12347 plate, then a MS9144-01 or B-1104 gasket against the governor. Here is a diagram from the Mooney document listed below that shows it best.
Here are references starting with the primary sources, Lycoming, the FAA and Hartzell.
Lycoming Service Instruction 1438A
http://www.lycoming.com/content/service-instruction-no-1438a
FAA Special Airworthiness Instruction NE-06-08
http://www.cessna.org/documents/public_info/saib/saib-ne-06-08.pdf
Hartzell Service letter HC-SL-61-277
http://hartzellprop.com/wp-content/uploads/HC-SL-61-277-R04-W.pdf
For more background information check these out. The Mooney document has the best diagram of what is needed.
http://www.ntsb.gov/about/employment/_layouts/ntsb.aviation/brief2.aspx?ev_id=20070703X00871&ntsbno=SEA07LA172&akey=1
http://www.mooney.com/en/si/M20-120.pdf
http://www.cardinalflyers.com/tech/info/govplate.php
http://www.fomento.gob.es/nr/rdonlyres/530301f2-9eed-4562-afc4-d0c27e26c2ce/105659/2008_023_in_eng.pdf
