R

rcfaubion

Member
I am trying to find info on installing the rear crank plug to change from f/p back to c/s. "Rosie" had a post a few years ago with a sketch of a special drift used to install this plug through the front of the bore quickly and easily. Any help would be appreciated (Rosie you out there?).
 
Hey Robert,

Here's a sketch of the tool that my friend Lucky loaned me (and one he had borrowed from somebody). The tool was machined from aluminum stock, and it took all of maybe 10 seconds to use once the plug was slipped in and upright behind the crosstube. Good luck! ;) Rosie

Prop_plug_tool.jpg
 
Hardwood

I made one a few years ago out of hard maple for my conversion. I will look for it tonight and try to get you dimensions. You can easily get the dimensions; measure crank bore and subtract 1/16, measure the plug you are inserting, then cut a strip of cardboard and insert it in the crank, trim till it matches the space between the spray bar and the crank bore. Repeat on the opposite side because the spray bar may not be centered ( I don't recall). Recess the end of the tool so it easily fits inside the plug. Cut a slot in the tool to match the spray bar with about 1/16" clearance. Make sure the slot is deep enough so that the spray bar can not be damaged. After you get the plug on the edge of the seating position mark the tool 1/2 inch out from the edge of the crank so you can measure the amount you have seated it. The hard part is removing the old plug. Lycoming says to treat the spray bar as if it was made of glass. I spent 2 hours getting the old plug out and I have no regrets that I did not damage the spray bar.
 
Hardwood tool

Rosie said:
Hey Robert,

Here's a sketch of the tool that my friend Lucky loaned me (and one he had borrowed from somebody). The tool was machined from aluminum stock, and it took all of maybe 10 seconds to use once the plug was slipped in and upright behind the crosstube. Good luck! ;) Rosie

Prop_plug_tool.jpg
Click to expand...

The main diameter is 1.75", the recessed diameter of business end is 1.5", total length 7.5", slot is .6" by 2.5" deep, slot is not centered; .8" from inner slot to main outside wall on one side, and .37" on the other "prong". In other words the slot creates 2 prongs that go past the spray bar, one prong will have a thickness of .8" the other .37". Dimensions are not critical as long as the spray bar is avoided and you have a reasonable seating area to hammer the plug in.
 
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