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Changing prop lugs O-320

P

punkin

Well Known Member
In my attempt to make the best correction for CG on my airplane, I spoke again with Sam @ Saber, who made my prop extension and crush plate. He said I can go to a 20lb crush plate, but he wants me to upgrade my bolts from 3/8" to 7/16".

His logic makes sense, so I'm not questioning that, and he can do all the changes to the prop extension...

The question is, can an average guy swap out the lugs on the engine without special tools and lots of cussing, hassle, or damage? I'm not a builder, I run an automotive shop --I've just never messed around with something like this.

No problem? Use caution? Run away? What sayeth the experience of this group?
 
lugs

Easy-peasey

Just use some sockets to make a 'press' and a bolt . They will come right out.
 
Cool, and to reinstall?

I can't imagine there is clearance to reverse the process...do I just tap them in? Do they "seat" to a specific depth, or is there a depth stop?

I haven't had my prop off in some time, so I'm struggling to visualize exactly what I'll be tackling...

Thanks!
 
Install lugs

Install just the reverse. Use the sockets and a bolt to pull them into place. The have a ledge on them that will stop when they are fully seated.
 
And used prop lugs are usually available from engine rebuilders who save them from rejected crankshafts.
 
Check out this Lycoming Service Instruction, 1098K:
https://www.lycoming.com/sites/default/files/SI1098K Propeller Flange Bushing Location.pdf

This S.I. shows the stock bushing configurations for the Lycoming engines, and even gives the dimensions of each P/N bushing. If any are loose in the flange, they can be had with oversize O.D. (P05, P10). Use this S.I. and advice from Saber to help get and install the correct bushings.

I just switched from a Sensenich FP to a Hartzell CS prop and had to change all my bushings. Our local engine shop exchanged them, no charge.
 
Anyone out there happen to have a set of 3/8" lugs for an O-320?

Working on a prop swap.
 
punkin said:
...he wants me to upgrade my bolts from 3/8" to 7/16".
Click to expand...
Wait a minute now...isn't he talking about the prop bolts, not the bolts that hold the extension onto the crankshaft? Those are already 7/16", I think. I have a wooden prop with 3/8" holes which I had to drill out to 7/16" to accommodate the Saber extension.
 
Bushings

0 320 can be 3/8 or 7/16 flange bushings.
Instead of using the proper size bolt use an undersize threaded rod and heavy washers to install the new bushings. Much simpler and faster.
 
Can the socket and C-clamp technique be used on a narrow deck 540? I tried an oversize shallow socket quickly last evening and couldn't find a spot where the tooling would fit due to the case nose profile being in the way.

Am I not holding my mouth right? Do I need to look for a shallower than "standard" socket?
 
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