Sunday, November 20, 2016

Engine DISassembly (Part 3)

I've been stuck trying to find the right tools for the last week or so, and then trying to find the time, but I finally made some progress. The pictures below show a collar assembly on the front of the motor, behind the prop hub. Apparently this setup is an anomaly - no one I spoke with was able to identify it. There are 4 screws that hold the front collar onto the back collar, which has one screw into each side of the case. Once I got the right size hex key, these came off and the case came apart.

These two collars house an oil seal around the crank shaft where it exits the case. My first inclination is to replace the seal, but I'm not sure what kind of damage I might do removing the prop hub. I'll have to think about it.

Once the case was split, I pulled all the cam followers and labelled them so I could replace them in the same locations. I'll be taking a lot of pictures once I've cleaned things up, but the camshaft looks like it's in great shape, so that and the followers will probably stay.

The inside of the engine wasn't as pretty a machining job as I'd expected, but everything turned nice and smooth when it was all together, so I'm not too worried about it. I haven't found a reason for the fine metal shavings yet, which makes me uneasy. 

This is where I left it. There are only a couple of things left to do on the case before it can be cleaned up and inspected, and I don't expect the crankshaft assembly will be difficult to take apart. After that I can begin blueprinting, clean and inspect, order my parts, and put this thing back together.

Sunday, November 13, 2016

Engine DISassembly (Part 2)

Not much progress today, but I got a little further. I keep running into bolts that I don't have wrenches for, although hopefully that will stop soon. The main thing I accomplished today was setting up a table to work on, covered in plastic, and transferring the engine block from the stand to my new "workbench."

I got the pistons out, which ended up being easy enough... the Teflon buttons really were just floating in there, but I needed something sharp to stab the sides of the buttons to get enough grip to remove them. I forgot to take pictures of them tonight, but when I get into working on the cylinders I'll be spending about a paragraph on how crummy those buttons are.

Removed cylinders yesterday, but they're all laid out in order here. You can see the lower right cylinder has a lot of corrosion on the outside of it - the other three cylinders aren't corroded much at all. I think the corroded cylinder was a quick replacement to avoid a more serious rebuild earlier in this engine's life.

Another disappointing discovery when I removed the accessory case that covers the flywheel - the teeth are chipped pretty bad on about a quarter of the flywheel. Not messing around with that - I'll have to replace it.... unless they sell just the ring gear for it. I'll look into that...

I also removed the valve springs, and while those all seem to be in good shape, I did notice that the same cylinder with lots of corrosion also has mismatching valves.... the valve on the far left below has almost no carbon deposited, not to mention is shaped different. I'll have to make a decision on whether or not that is an issue/will bother me enough to get new valves.

And here's the part where I don't have a big enough wrench - or rather, big enough socket. Not sure a wrench would be really effective, since this is recessed inside the flywheel.

Tomorrow I'll pick up some more specialty sockets, and hopefully make some more progress on tearing this thing apart. My goal is to have a semi-final list of parts to order by the end of the coming weekend, as I suspect some of the parts will take some time to acquire... especially if I wait until the holiday season.

Saturday, November 12, 2016

Engine DISassembly (Part One)

After a bit of a hiatus, I began tearing down the engine I intend to hang on the front of the plane. I'll be using a 2180 Volkswagen engine, originally built for aircraft use by Hapi a number of years ago. When I received the engine, it was mostly assembled, but I wanted to tear it down, blueprint everything, and rebuild it myself so I know it's done right. Besides, it's hard to powder coat an engine block with stuff attached. So today I finally started yanking stuff off.

Engine on the stand, ready for disassembly:

First I pulled the intake manifolds and spark plugs. I'm working on this engine away from home, so I lack most of my tools and all the helpful things like oil drain pans... Therefore, I used an empty lemonade bottle to catch the old oil. Seemed to work.

I pulled the valve covers, then the valve train. Sure looks a lot simpler than any other engine I've taken apart.

Next step was to pull the head, which came off pretty easily, along with one of the cylinders. The other cylinder wasn't much trouble.

The pushrods and pushrod tubes fell right out as well, and I hung onto those for referencing when I reassemble. I'll probably replace them, along with a good deal of other hardware inside.

The left head valve train was shimmed about .122 off of the head.

The right side wasn't any more difficult than the left. Valve train shimmed .088 on the right side.

I'd have liked to do more, but a little research is in order. The pistons are held on by a large pin, and that pin is usually captured by E-clips or similar devices. Whoever assembled this engine most recently used Teflon blocks that ride against the cylinder wall instead. Nice idea in theory, but if they ever wear down, there wouldn't be anything holding the piston pin in place... which would mean a catastrophic failure. I also noticed that one of the Teflon "buttons" had picked up some debris and scored the cylinder wall with it... another thing that wouldn't happen with the right hardware. I'll have to take some measurements and decide whether I want to hone that cylinder or replace it.

This is where I left off today.

You can see the Teflon "buttons" in the picture below - they're the white circles on the sides of the pistons. I have no idea how to remove these, unless they're to be pressed out with the piston pins. Time for research.