Found this description of a major alteration in the paperwork of a BC12-D that I'm considering buying.
What/why would someone do this? I'm confused.
Also the notation indicated that they machined off the -12 starter mounting ears - see photo below - arent the circled areas the starter mounting ears? If they're not, please forgive my ignorance - I've never seen a starter for a plane that didn't necessitate the use of my arms, so the whole area is new to me.
This engine was converted from the C85-12F configuration to the C-85-8F Version.
This alteration is the same as that which was approved on June 7, 1963 for Taylorcraft Model BC-12D, Serial Number 7274 N43615 and also approved on a Piper J3C-65 Serial number 8318 N53305 on January 26, 1999.
The rear crankcase cover assembly, Continental par number 6726-A1 was removed and replaced by Continental rear crankcase cover assembly part number A4587.
The Alteration was accomplished as follows:
Removed all -12 rear cover mounting studs. Removed part number 23487 starter pinion pivot.
Replaced part number 35016 crankshaft gear with part number 530641 gear. Replaced part number 530535 camshaft gear with part number 3506 gear. Fabricated and installed an aluminum plate .250 inch thick to replace part number 35033 oil cooler pad cover.
Part number A4587 crankcase cover assembly was mounted on the crankcase using the existing dowel pins as line-up. The dowel pins are in identical location for either crankcase cover. The two lower stud holes are already in the correct position and are used on either rear cover. Using the A4587 crankcase cover as a template, the new mounting stud hole were marked, drilled and tapped.
Ten part number 401809 studs were installed in the crankcase. Machined off the -12 starter mounting ears. No other machine work required.
This alteration is the same as that which was approved on June 7, 1963 for Taylorcraft Model BC-12D, Serial Number 7274 N43615 and also approved on a Piper J3C-65 Serial number 8318 N53305 on January 26, 1999.
The rear crankcase cover assembly, Continental par number 6726-A1 was removed and replaced by Continental rear crankcase cover assembly part number A4587.
The Alteration was accomplished as follows:
Removed all -12 rear cover mounting studs. Removed part number 23487 starter pinion pivot.
Replaced part number 35016 crankshaft gear with part number 530641 gear. Replaced part number 530535 camshaft gear with part number 3506 gear. Fabricated and installed an aluminum plate .250 inch thick to replace part number 35033 oil cooler pad cover.
Part number A4587 crankcase cover assembly was mounted on the crankcase using the existing dowel pins as line-up. The dowel pins are in identical location for either crankcase cover. The two lower stud holes are already in the correct position and are used on either rear cover. Using the A4587 crankcase cover as a template, the new mounting stud hole were marked, drilled and tapped.
Ten part number 401809 studs were installed in the crankcase. Machined off the -12 starter mounting ears. No other machine work required.
Also the notation indicated that they machined off the -12 starter mounting ears - see photo below - arent the circled areas the starter mounting ears? If they're not, please forgive my ignorance - I've never seen a starter for a plane that didn't necessitate the use of my arms, so the whole area is new to me.
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