What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

Help with prop flange to prop

MrNomad

Well Known Member
I am helping a friend install his rebuilt O-320 donated from a 172. The prop flange on his rebuilt O-320 has 1/2" bushings for the prop bolts. His propeller has 7/16" holes and bolts. I noticed that Spruce sells replacement bushings so is it a simple matter of pressing out the old bushings from the flange and pressing in new ones? Would it be easier or more advisable to send the prop to Warner and get the holes enlarged?

The crank is installed in the rebuilt engine so removing the old bushing w/o damaging or bending the crank is of concern.

Suggestions welcome.
 
Pretty simple to remove old bushings. Place an oversize socket on the backside of the flange and a washer on the front side of the bushing and the backside of the socket. Insert an undersize bolt/nut and tighten. This will push the bushing out of the flange and into the socket.
 
Thx Mel

Pretty simple to remove old bushings. Place an oversize socket on the backside of the flange and a washer on the front side of the bushing and the backside of the socket. Insert an undersize bolt/nut and tighten. This will push the bushing out of the flange and into the socket.

I recommended the builder balance the prop after all of this is done.
 
I guess I should have mentioned installation of the new bushings. Also simple; just place the bushing in from the back and place the socket on the front side. Insert bolt/washer and pull the bushing into place.
 
0-320 crankshaft bushings

I am helping a friend install his rebuilt O-320 donated from a 172. The prop flange on his rebuilt O-320 has 1/2" bushings for the prop bolts. His propeller has 7/16" holes and bolts. I noticed that Spruce sells replacement bushings so is it a simple matter of pressing out the old bushings from the flange and pressing in new ones? Would it be easier or more advisable to send the prop to Warner and get the holes enlarged?

The crank is installed in the rebuilt engine so removing the old bushing w/o damaging or bending the crank is of concern.

Suggestions welcome.

An 0-320 is either set up to use 3/8” or 7/16” prop bolts. The 360’s use the 1/2” prop bolts. An 0-320 crank flange can not accommodate the drive lugs for 1/2” prop bolts. As Mel says simple to swap out the correct drive lugs (bushings). If you need different drive lugs new ones are expensive, look for some used ones or failing that call Sam at Sabre he makes new experimental ones.
Duff
 
One of the bushings is a different size so you can find TDC.

I do not know if the hole in the flange is also different, but it would be wise to mark the flange where the indexing bushing goes before you take things apart---just in case the flange holes are all the same, and it is an oddball bushing that creates the indexing.
 
An 0-320 is either set up to use 3/8” or 7/16” prop bolts. The 360’s use the 1/2” prop bolts. An 0-320 crank flange can not accommodate the drive lugs for 1/2” prop bolts. As Mel says simple to swap out the correct drive lugs (bushings). If you need different drive lugs new ones are expensive, look for some used ones or failing that call Sam at Sabre he makes new experimental ones.
Duff

+1

The bushing OD is the same for the 3/8 and 7/16 versions. The 1/2" version has a larger OD. If the 320 crank trully has 1/2" bushings, that means someone drilled out the holes in the flange and you will no longer be able to install std 7/16" bushings unless Sam will make you custom bushings that fit the larger OD of the flange and the smaller OD of the prop. I suppose it is possible that Lyc made a version of the 320 crank sized for 1/2" bushings, but I was not aware of it.

Larry
 
Last edited:
Back
Top