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How do you separate the case on a widedeck O360

jscottpilot

Active Member
I bought an o-360-A1G6D for rebuild. I am disassembling the engine so that I can send the crank and case to be inspected. The seller said he guaranteed they would make overhaul. I have two months to get them inspected. I have disassembled every thing but the crankcase is not going to separate easily as indicated by the overhaul manual. Could you give me your personal experience on how to separate this thing.

I removed all perimeter bolts and nuts and two throught bolts in forward section and the nut just above the camshaft. All cylinders removed etc. Am I missing something? Someone said the through bolts have to be driven out. I find that hard to believe. That seems like alot of pounding on a delicate aluminum block. According to the overhaul manual you just remove all the bolts and lift one side of the case from the other.
 
Extract from the overhaul manual

The manual says to use a soft hammer for that.

crankcasesplit.jpg
 
I guess I am just going to have to ship it to a shop that can do it. I just cant bring my self to hammer on something that I just paid thousands of dollars for. Hammering a rivet is one thing but an engine case is another, for me at least.
 
SPLITTING CASE

There are short dowels around the main bearing bores that are a very tight fit. You need to borrow or make a case splitting tool. A homemade one can be very simple-some pieces of cold roll flat bar stock welded or brazed together. Drilled to fit over at least two studs, preferably four on both cylinder pads on one side. Two long screws to tighten against the crank. Two radiused aluminum blocks to protect the crank. Tighten the screws against the blocks evenly until the dowels disengage. The overhaul manual should have pictures of the fancy tool the factory sells. This should give you an idea haw a simple homemade tool can be made.
 
I did not see that tool in the O-360 overhaul manual but did see it in the O-540 overhaul manual. It is part number ST-122. an O-540 is just an O-360 with two more cylinders. Do you think that is the same tool you are describing? I can rent that tool from Lycoming for 50 bucks.
 
tool

There is a case splitting tooling that you can use. I borrowed one from a friend to split mine. It consists of two plates with bolts attached. You bolt it to the sides of the case and tighten them together. Eventually, it splits the case. This tool is available to purchase from lycoming. I am sure it is very expensive. Most reputable engines shops probably have them.. My recommendations is to do it right with the right tool..

Patrick
 
The right tool will save me from damaging the case. I don't want to pay 50 dollars and rent the wrong tool. Do you think the ST-122 lycoing part number tool they use to split the O-540 will work on the O-360? The description sounds the same. If anyone has a tool they know will work I would love to rent it and pay you handsomely.
 
Just a thought, when I split my case I had all the hardware removed and couldn't get it apart. It turned out the rubber nose seal near the crank flange was the last thing still holding it together.
 
If you have no access to a splitter - which works best.... some pieces of handy dandy lumber (2x4's) have been rumored to work pretty well when combined with the appropriately sized persuading device. :)

Cheers,
Stein
 
Protect those studs before applying a hammer

My through bolts are not moving. tell me how to get them out.

Before any hammering is done on them, make a tool to protect those studs. Take a piece of 1.5" or 2" diameter round aluminum stock. Cut it about 3 inches long. Now drill (about 1" deep) and tap (a bottom tap works best) into one end so that you can screw this protective "cap" over the stud to be hammered on. This way you won't damage the ends of the studs.
Charlie Kuss
 
The assembler has to use a hammer to install the studs. You will need to use a hammer to remove them. Do not hammer directly on the threaded end of the stud unless you plan on replacing them. Also be sure you pick the thru bolts to hammer on and not the case mounted bolts.
 
Before any hammering is done on them, make a tool to protect those studs. Take a piece of 1.5" or 2" diameter round aluminum stock. Cut it about 3 inches long. Now drill (about 1" deep) and tap (a bottom tap works best) into one end so that you can screw this protective "cap" over the stud to be hammered on. This way you won't damage the ends of the studs.
Charlie Kuss

I have a tool I made exactly as Charlie describes, except I made mine from steel. You drive the thru bolts down with a hammer, and finish driving them thru with a brass drift.

There is a .000 to .003 interference fit for the studs, and really the only way to check the fit is by how easy they drive thru the case halves. The middle of the stud is tapered, so you only have to drive them about 1-1/2" or so before they will fall out. If you find any loose ECI makes oversize studs. Sometimes swapping the studs between locations will take care of any loose fits.
 
it is separated

I just separated the case. I removed the 4 through bolts by putting large washers on the studs and then drawing them out with the nut that goes on the stud. They were tight but came out fairly easily. As soon as I pulled the four studs out I tapped the case with a rubber mallet and it essentially separted with one light tap. The seal on the nose of the engine held the nose of the engine together. It required some coaxing. I just used something soft to pull down on the seal once I had room. If you have to do this remember the rear through bolts are not really through bolts. They are anchored or screwed into one side of the engine. No need to remove them. Thanks for all the help.
 
Found this online for how to split a case that would be helpful for the next person that needs to split one. Myself included......

http://www.ryanmachine.net/Docs/Let's-Split.pdf

If others reading the thread in the future find this, they will already know that the case splitter is the preferred way of splitting the case. The newer wide deck cases have a stud and nut behind the accessory case that must come out before splitting. On the narrow deck engines, the stud is a bolt. The nut must come off before trying to split the case.

For those of us do not want to PAY for a case splitter, put the cylinder hold down nuts back on the through studs so that all the threads near the end are protected. You can then hit the thru studs with a "dead blow" hammer for about 20-minutes. There are six (6) thru studs on the 360 / 320 Lycoming engines. The case will separate. DO NOT put a screwdriver or metal pry bar between the case halfs to help it along.

I split a 320 narrow deck and 360 wide deck with the above method during the past 6-weeks. I had originally planned to buy the case splitter that is listed in the above article link.
 
case

Set the case on the work bench and get two straps and run through the case where the cylinders bolt on each side adjust length of first strap to edge of table and a ratching strap on other side tighten slowly and tap with mallet it will come right apart.
Bob
 
Serial #?

If the serial # ends with an "A", it's a wide deck and the thru studs drive out. Like others mentioned you can "suck" 'em out with a nut (use a "high" nut to minimize thread wear). So put some tension on the stud with the high nut and smack it from the other side a few times. If the nut is now loose your making progress, tighten it up again and repeat. The two rear studs are not through studs, they are "mounted" studs and threaded into the opposite case have, so make sure you identify which of the 4 studs are through studs. Once they are removed the case will come apart easily. Never but never drive anything between the case halves to force it apart.
An aluminum or brass drift and hammer will work much better than a dead blow hammer.
Tim
 
Okay, here is my experience. First time case splitter (wide deck IO-360) :rolleyes:

First, I would not use the washers to pull the thru studs. I did not, but somebody did it on my engine. This is the first run engine, so it was probably the builder (unless they took a used case?).

Look for the washer imprint. The engine had a happy 2100 hour run, so seemingly wasn't an issue. Still, though.

IMG_6985.jpeg

Not sure why would one use washers during the build. Substitute for a pressure plate, before installing the cylinders?

For splitting, I used the following high-tech tools I made from whatever scrap aluminum I had.

IMG_6998.jpeg

The plate on the left is my mini-pressure plate for pulling the studs. It goes over two studs so it does not turn (it has a large area so it wouldn't turn even if it wasn't over two studs).

IMG_6992.jpeg

I plan to replace the studs, so I didn't bother with the longer nut. I've never torqued cylinder nuts before (so I don't have a calibrated elbow), but the force I applied did not seem excessive.

Then, after all four studs were removed, I used a piece of plywood to push against the crank, put a plate over it and torqued it slightly. It popped with a very little force. This is also not a 50 year old engine, so YMMV.

I only made one "splitter", so I moved it between the cylinders to make sure case opens evenly. Also, you can see I put two bolts in the bottom of the case -- the case wanted to split on the bottom more than on the top.

IMG_6997.jpeg

Don't recommend using a board as it can split before the case!

IMG_6995.jpeg
 
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