Engine Assembly

Getting started

I started off by cleaning, masking, and painting  the case halves. My theory is that red engines make more power. Following the manual I installed the connecting rods onto the crank, and the gear onto the camshaft. I went for the pre-fitted hub option. I've done this type of thing 20 years ago and it was worth it to me to have that very critical step completed.

Fitting the case halves together

The bearings are fitted into the case halves, fitting onto dowel pins in the bores to keep the bearings from turning. It's tricky getting the halves together because of the lifters on the side of the case you're lowering onto the other side holding the crankshaft.  In the first picture below you can see where I have placed sharpie marks on the places where the crank bearings line up with the dowel pins and settle into place in the case half. The cam bearings and cam are installed at this time. Then the case halves are mated and torqued together.

Nikasil cylinders


When I first started trying to fit the first cylinder (jug) assembly, the cylinder wouldn't fit down into the case. First there was interference between a cooling fin and a case nut. I removed enough fin material to clear and it still bound  up halfway in and rocked back and forth, indicating some high spots which I could feel on the base of the cylinder. I decided to smooth down the high spots at the base of the cylinder with a mild file and ended up catching an edge of the plating and chipping it off on the inside of the cylinder bore. Of course this happened on a Saturday morning, so I knew I had a few days before I could talk to Kerry at Sonex. I looked at the other cylinders included in my box and found one other piston with the same rough high spots and two seemed to be much more smoothly finished. There is one picture showing a "good" cylinder in the foreground and a problem one in the back. You can see a line about 1/8 inch from the bottom edge that is not machined on the background cylinder and it appears to be machined all the way to the bottom on the cylinder in the foreground. That cylinder is actually machined all the way to the bottom for about 1/3 of the circumference of the cylinder, and you can see the 1/8 inch strip along the bottom on the other 2/3 but there doesn't seem to be a "step" where the machining stops. In the last photo you can also see a difference in the machining on the inside of the cylinder bores. The foreground cylinder machining stops much higher in the inside bore, slightly above the line of the top of the plating chip on the background cylinder. I'll wait to see what Kerry's advice will be.

Work in progress: 5/9/10

Lonely engine waiting for some cylinders

5/25/10: Received replacement set of pistons and cylinders from Sonex. I used the time to make decisions on other details such as working on the fuel system plumbing design, buying instruments, playing with panel design, as well as some house projects...

7/30/10: Back from Oshkosh with a new burst of enthusiasm. The best thing I came away with was the thought that I should just go ahead with getting the airplane together and flying and then work on the tweaks that I have seen and read about since I started building 3 1/2 years ago. Things like disc brakes, vernier throttle, different instruments, etc.

I spent several hours with emery cloth smoothing down the bases of the new cylinders, getting the nikasil plating off the outside of the bases so they would fit into the case. I used a red sharpie to line the surface of the cylinder base and then when I tried to fit them into the case, it would remove the red marker to show where the interference was. I had to do this to three of them, one fit right in with no work. The next evening I came home prepared to measure deck height on the installed pistons and discovered one of the NEW cylinders I had received has a bunch of tiny pock marks in the cylinder wall plating---crap! I hadn't thought to inspect the bores of each cylinder when I was fitting them to the case. I've got to send Kerry another email about this. I'm afraid to use this cylinder, afraid the nikasil plating will come off inside the cylinder bore. I'm going to ask him to send me the regular pistons instead of these "upgrades". I have kind of lost my faith in whoever this supplier is.

8/3/10: In the pic below I had fitted the first piston/cylinder into the case so I could measure the height of the piston compared to the height of the cylinder. This is the deck height. When I started to do the second deck height measurement was when I noticed the pock-marked cylinder wall. I emailed Kerry that night and he responded the next day. He gave me the choice of sending me a set of regular cylinders or he said he would hand pick another nikasil cylinder and send it out. I responded to him that I wanted to stay with the lightweight nikasils and the next day he had one in the mail to me. I continue to be really pleased with the responses I get from the guys at Sonex.

8/9/10: I received the replacement cylinder and finished measuring the deck height for  all the cylinders. I was able to pick out the needed cylinder shims and install the cylinder/piston assemblies and cylinder heads. When I first assembled the heads onto the tops of the cylinders, a couple of the pushrod tubes  were loose- too short. I had to remove the pushrod tubes and stretch them out so that they would be tight in place when the head was tightened down.

Fitting pushrods and rocker arms:

8/15/10: The cylinder head studs extend far enough to interfere with the installed rocker arm assemblies, so they have to be cut at the ends to allow clearance (3 on each side). At this point in the assembly process, you already have the heads installed. I taped up like crazy to avoid getting any crap in the engine.  8/31/10: In the last pic you can see the rocker shaft assembly bolted down and the shortened studs behind them.

First shot below is after I installed the rear main seal. It's fairly easy to tap it in place with a very light hammer and get it flat. The second shot is after the accessory plate, flywheel, stator, and ignition trigger shaft has all been installed. The flywheel has no mass to speak of. It does hold the ring gear and the magnets for the 20 amp alternator.  You can see the 6 wires from the 2 CD ingition triggers, and the thick insulated lead from the alternator. All the billet aluminum pieces are very nicely done. Last picture: aerovee 2.1 # 578

In the picture below is a front view of the engine, showing some of the block off plates and the oil pump with outlets for the oil cooler.  The opening with the gasket will get a plate with the oil temp sender screwed into it.  Next two shots are after engine was hung on mount for the first time.  The two middle head studs sticking out beside the taped off intake ports need to be shortened to allow clearance for the intake fitting.

Below is a close up of the mount with bushings and washers. Four 1/4 bolts hold the engine on.