Firewall Forward - Engine

2005-03-13 - Engine tear-down. (8.0 Hrs).

Previously, I had all of the bolts off of the engine, ready to separate the housings, but it was late, so I waited to figure out what else needed to be done before doing the separation. As it turned out, there was nothing more to do than simply pull each housing off of the eccentric shaft. The center housing does require you to jimmy things a little, but it's no big deal. What I did was to remove the two housings and the rotor from the rear, then the two from the front. This left just the center housing and the eccentric shaft, which were easily separated.

This is a messy operation. Oil and water will leak from each part. Just lay down some newspapers. As each housing came off, I thought that things didn't look too bad. The rotor housings looked good, and the steel side housings appeared to have oil marks where the rotor side seals were sitting.

As they say, first looks can be deceiving. After wiping off the oil on the side housings and doing a closer examination, I realized that those were not oil marks, but rather heat discoloration. Then, I discovered a crack, about 1" long on the center housing. Apparently, this engine got pretty hot.

The center housing is toast, but all is not lost. I have another whole set of engine parts, so, I might have a spare. I haven't had a chance to go through all of the other parts--I don't want to get things mixed-up. Not that it matters that much, now, but I decided to do a full clean-up of the disassembled engine before deciding what to do about the rebuild.

I started cleaning each of the housings using gasoline. This is what my dad and I used when I was a kid, so that's what I started with. After spending two hours on Friday night, the garage stunk pretty bad. I was sure that my wife was going to give me whatfor, so I closed the laundary room door to try and hide the smell. On Saturday, I found an industrial degreaser at Walmart, so I thought I would give that a try. It worked as good as the gasoline, without the smell, so I would recommend this instead of gas.

Anyway, I spent 4 hours cleaning the housings on Sunday. Unfortunately, during the process, I discovered another crack in the frount housing. So, it looks like I need two good housings from the second batch of engine parts. Things are not looking too good for my $200 engine, but I am getting a lot of valuable experience.

Now, I am starting to think maybe I should just buy a rebuilt engine, instead of trying to find a used one to rebuild. I mean, there is no way to know if an engine has been trashed when you buy it on Ebay, until you get it and tear it down. On the other hand, there is no guarantee with a rebuilt engine, either. I'm not so sure if I want to fly behind a $2000 engine that I haven't looked at inside.

Anyway, here is more of the tear-down and clean-up.

Here's the rear housing and the rear rotor housing.
Which leaves the rear rotor attached to the E-shaft.
Here's all the pieces. I'm sorry, I couldn't show each part coming off of the engine, but this is kind of a mess. Having to wash your hands after each part is a bit of a pain. Trust me, it was real simple. You just slide each housing off, one-at-a-time. There were no problems, other than the center housing, and even that was easy. I did this with the engine sitting horizonatlly on two 2x2s--no problem.
Here's the big crack in the center housing You can also see the discoloration, where the side seals started to burn. It looks like someone ran this engine without oil, or maybe without water.
There's a lot of carbon on the rotor faces. Also, you may be able to see the burning on the side of the rotor.
This is what I did with that beautiful weather that we had today. I washed parts.
ZEP Industrial Purple, worked great. Gas on the right, not so good.
This is a better picture of the burning on the side of the rotor. The center part of each side seal is completely gone.
The other side of the rotor is not so bad. The bottom and left side seals are ok, but the right side seal is burnt quite a bit.
One rotor housing, all clean. At least something looks useable.