Ivan's RV-7

Splitting the caseTimer icon3h

January 25, 2023

Finally, split the case!

I started with the removal of the accessory case and everything that is in that area (idler gears shafts, oil pump, that nut behind the camshaft). Removing the nut behind the camshaft was a bit tricky. Even though my cylinder wrench did fit, I was only able to turn it about 5° before it got stuck. After some manipulations, I was able to remove the nut by only grabbing it partially. However, I don't think it will work well for installing the nut, so I will need to figure out a better wrench.

After that, I removed all the fasteners on the case perimeter and moved to the thru-studs. The idea was to remove them first, to simplify the case splitting.

There is a trick to use washers to pull the studs, but it's known that they might leave marks on the case. Well, somebody did use washers on my case. All thru-studs have marks around them.

Marks from the washers.

I quickly fabricated a plate to put over the studs so it can't rotate and also has a large surface area to avoid marking the case. The tool is on the left in the image below, the black plate.

The tools used for the case splitting.

This is how I used it to pull the stud. I put the cylinder nut on the stud and torqued it until the stud moved. Once the nut gets to the shoulder, remove the nut, put some washers on top, and repeat.

Using the plate to pull the stud.

There are recommendations to use a longer nut to protect the thread, but I did not bother since I plan to replace the thru-studs. Also, the torque did not seem excessive to me. Perhaps, less than the final torque required?

The studs are pulled out.

The studs are pulled.

Then I moved to splitting the case. I used the tool on the right from the photo above. The idea is very simple: the plywood part goes against the crankshaft and then the plate pushes on it. Since only the two rear studs plus the sealant keep halves together, not much force is required.

This is how it looked.

Using the tool to split the case.

I only made one tool, so I had to move it between two cylinders to make sure that the crankcase is split evenly. Also, you can see I put two bolts on the bottom of the case. I did it so it splits more on the top because at first, it split more on the bottom.

Finally, the case is split.

The case is split!

The first iteration of the tool, made from a board, split before the case, however! I was kind of hoping it will last enough to separate the halves, but it did not.

The tool split before the case!

The halves of the crankcase.

The right side of the case. The left side of the case.

The next step is to sort the parts between "keep/overhaul" and "discard", clean the "keep" parts, and put them in long-term storage. It was a fun project, but I won't need an engine for a while, so better to keep the parts safe, under a thick layer of LPS-3!