0-320 Narrow deck case splitting plate plans and 4 cylinder hold down plates

[Steve Pierce]

Good to know. I see what you mean now. Will work on both.
Right is for narrow deck, left is wide laying over the universal Lycoming tool.
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[Frank Green]

Thanks for the pictures. So your tool pushes on the crank through a brass block? I think I would prefer to use a tool that pushes on the through studs to separate.

Looks like you pulled the through studs out first. Did you double nut them or use a stud puller tool?

PS - I grew up in Constantia, NY. Really small town not too far from Frankfort.

Narrow deck the through studs are double threaded and screwed into the case on one end. Really doesn't take a lot of pressure to seperate. Just need to do it in the right place and depends on what was used to put it together. Once you get it started no big deal. Nothing wrong with pushing on the crank. Strongest thing in the whole deal.

[Steve Pierce]

I agree. I have split cases with plastic wedges and have the case splitters makes an easy job of it. Just make sure you have every fastener removed or you can chase your tail. Been there and done that.

[Vagabondblues]

So separate with slide hammer on cylinder base nut. Install and preload bearings with torque plates. The SI for crankcase preload has been rescinded.

[Steve Pierce]

I have used the slide hammer on the wide deck and it is pretty easy and quick. Like Frank posted, the narrow deck has the studs screwed into one crankcase half instead of pass through like the wide decks.

I maintain a couple of Cub Crafters NX Cubs with the IO-390 and like it that Lycoming has made all of those manuals available online. Saves money and the latest version is always available. They have also gone further in depicting things in pictures.