[Jerry Cochran]

Dear Lyco experts,

I'm working on disassembling an O-360 Lyco and been told I'll need a special tool to split cases. Anyone know about this and if true can you point me in the right direction?

Many Thanks,

 

[rocketbob]

What I do: I have a tool I made that screws onto the thru-bolts and I hammer them thru the case. Once those are out I'll then CAREFULLY hit the case with a dead-blow in the accessory case area to get the case halves started loose. Then pry apart with pieces of wood or plastic. As long as you're careful you don't need the tool. The thru bolts will have to be removed regardless to check fit, so I feel it makes more sense to do it from the get-go.

 

[Jerry Cochran]

Thanks Bob,

How tight are the thru bolts usually? Can one install a couple of nuts and tap out with a wood mallet for instance? I can make most any jig or tool if I have an idea what it's like...

 

[rocketbob]

depends... IIRC they are a 0.000"-0.002" interference fit. If the fit is 0.002" it will take some pounding to get them thru, and a wooden mallet won't do much good. They are tapered in the middle and only engage the case for 2" or so the last bit you have to hammer with a brass drift.

 

[MikeT]

Splitting cases

An easy way to get the through bolts out is slide a couple of 1/2 inch drive deep well sockets on the stud, you have to figure the correct combination to get the desired length, then a washer and nut. Tighten until the bolt comes out. You have to change the combinations of sockets a couple of times to get it all the way out.
Some engines have a case bolt behind the camshaft gear, don't forget to take that out.

 

[Vern]

Lycoming rents case split tools...

...Thru their dealers. Takes about $1500 deposit. It's two heavy 1" steel plates, nuts, bolt extensions,etc. Procedure is shown in the manuals.

It's still a pain!