0-320
Posted: Fri Feb 17, 2012 5:26 pm
Re lycoming 0-320
Lycoming engines manufactured before 1964 (1971 for 540 series) were of +ACI-narrow deck+ACI- design. These engines used cylinder base hold down plates and internal-wrenching type cylinder based nuts. The narrow deck design incorporated anchored through-studs that are of an earlier design and created crankcase fretting problems. Anchor through-stud engines should not operate past factory recommended TBO time's because of the possibility of crankcase fretting.
After these dates, lycoming engines became +ACI-wide deck+ACI-. Wide deck engines have regular hex type cylinder base nuts and a thick cylinder base flange approx. 3/8+ACI- thick. The thicker cylinder base flange makes the wide deck engines slightly wider then the narrow deck engine. The switch from narrow deck to wide deck did not chnage the model number of the engine even though cylinders and crankcases are not interchangeable. Another method you can use to distinguish narrow deck from wide deck is by the engine serial number. If the serial number ends with the letter +ACI-A+ACI- it is wide deck (e.g., L-82374-27A).
Body fit through-studs (wide deck) are a newer design. They support the crankcase halves with an interference fit at the crankcase parting surfaces and are tensioned at both ends with a 1/2-20 nut. This increases the rigidity of the crankcase and prevents movement and fretting.
To make are long story shorter, buy a +ACI-wide deck+ACIAIQ-
Peter K
SR003
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Lycoming engines manufactured before 1964 (1971 for 540 series) were of +ACI-narrow deck+ACI- design. These engines used cylinder base hold down plates and internal-wrenching type cylinder based nuts. The narrow deck design incorporated anchored through-studs that are of an earlier design and created crankcase fretting problems. Anchor through-stud engines should not operate past factory recommended TBO time's because of the possibility of crankcase fretting.
After these dates, lycoming engines became +ACI-wide deck+ACI-. Wide deck engines have regular hex type cylinder base nuts and a thick cylinder base flange approx. 3/8+ACI- thick. The thicker cylinder base flange makes the wide deck engines slightly wider then the narrow deck engine. The switch from narrow deck to wide deck did not chnage the model number of the engine even though cylinders and crankcases are not interchangeable. Another method you can use to distinguish narrow deck from wide deck is by the engine serial number. If the serial number ends with the letter +ACI-A+ACI- it is wide deck (e.g., L-82374-27A).
Body fit through-studs (wide deck) are a newer design. They support the crankcase halves with an interference fit at the crankcase parting surfaces and are tensioned at both ends with a 1/2-20 nut. This increases the rigidity of the crankcase and prevents movement and fretting.
To make are long story shorter, buy a +ACI-wide deck+ACIAIQ-
Peter K
SR003
*----------------------------------------------------*
The Murphy Rebel Builders List is for the discussion
between builders and owners of Murphy Rebel aircraft.
Archives located at:
http://www.dcsol.com/murphy-rebel/lists/default.htm
*----------------------------------------------------*
-----------------------------------------------------------------
List archives located at: https://mail.dcsol.com/login
username "rebel" password "builder"
Unsubscribe: rebel-builders-unsubscribe@dcsol.com
List administrator: mike.davis@dcsol.com
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