Ran into a small problem today. I assembled the engine, made push rods and gaskets. After I installed the push rods, I set the valve timing. Then I checked the valve timing for cylinder number 2 and discovered the problem. When constructing the cam shaft I cut the second set of lobes 180 degrees out. The second set of lobes are supposed to be 90 degrees different from the first set. I rotated the cam the wrong direction when I made the second set of lobes.
Oh well, a cam is not too hard to make. I will try to start on it next weekend. (Dang rookie machinist!)
Note - 16-Aug-03: The lobes for cylinder number 2 are NOT 90 degrees out. They are zero degrees out. I had a problem getting it straight in my head.
Progress has been really slow lately. I don't seem to have much time for the shop. I have been able to make a set of rocker arms. I first thought that I would have the rocker pivot shaft go through the sides of the rocker box, and held in place by a pair of e-clips. But this seemed like a constant oil leak, so I tried to come up with another way to mount them. What I have here is a snap in pivot shaft. The support block is attached inside the rocker box, the rockers are assembled on the pivot shaft and the shaft is snapped into the support. The valves and the push rods will keep it from falling out. I don't know how well this method will work out. A lot of the support block had to be milled out to allow for the shaft to snap in.
The picture shows the support block with the rockers installed on it.
OK!! It has been a while since the last update. I have been working on a lot of different parts. I work on one part until I have a problem, and then move on to another part. This leaves a lot of unfinished parts. But, they are starting to come together.
Shown here is the latest version of the cylinders and heads. This is more like the style that I want. The heads are giving me lots of trouble. I can't seem to make an accurately sized hole that is 9/16 inch bore. I guess I will have to buy a boring head for small holes. You can also see the rocker box, this is the first one, and it seems to be working out good.
I have also been working on the distributor. I know that a waste fire system will work without a distributor but, I just want to make one.
Here is the latest view of the engine. I have added a front cover. The cylinder heads are some early prototypes that were assembled just for the photograph. I am still working on the cylinder and cylinder head combination. The final cylinders and heads will be made from bar stock.
It looks like this engine will weigh about 6 pounds when complete. I don't think that will be to heavy, all things considered.
Here are the valves. The exhaust is 0.375 dia. the intake is 0.475 dia. The stem dia. is 0.125. The over all length is 1.500 inches. It sure seems like a big waste to turn a half inch dia. bar into a 1/8 th inch stem. The stems have a small notch for the retainer to lock into.
They are made the same way as the valves for my first engine. They are just different sizes.
Here is how I determined the sizes and lift for the valves.
Designing the valves, and cam shaft.
This is the process for making the valves.
The cam shaft is finally done. It came out looking really good. Thanks to Dave Bowes for the timing specs. The flat on the end of the cam shaft drives the oil pump.
I have a preliminary cylinder head and I am almost ready to give the engine a trial run. I plan to assemble it with only one cylinder for this trial run and I will probably use glow ignition also (for the trial run only as the ignition parts are not yet made).
Here is the piston mounted on the rod. I cut down the sides to reduce the weight. There is 2 compression rings and an oil ring that will go on it. The compression rings are already made. The oil rings were made, but I broke them all. They are so fragile that I am going to wait until the engine is complete before I make new ones.
A side note:
I have made a rod for the engine. The second rod that I made was slightly lopsided, (about 0.070") I mis-calculated on an offset some where. The rod is made from 6061-T6 aluminum. When I made the rod, I found out that there was very little clearance in the crankcase where the oil channel goes across. The first rod that I designed would not clear the oil channel. I had to make the rod cap a little smaller and narrower. (I always try to make things as big as possible) I have assembled a step by step guide for the rod.
This is the engine with both cylinders mounted and the back cover on. The back cover covers the oil pump and is a part of the oil pan. the upper part of the cover is mostly empty. I thought about putting a generator coil inside it, but that is in the future... when the engine is complete and running. The oil pump is now inside the cover. The small shaft is to drive the points. I have made the cylinders as shown here, but I don't really like the look of them. I want a more modern look, with more, smaller, closer cooling fins. These are cast alum. I want to find some 2.25 inch aluminum bar to make them from. The back cover made the engine look really big, and I still have to put a front cover on it. The cylinders look really short and small but the head will change the way they look.
|This pic shows the rear of the engine with the oil pump mounted. The long skinny shaft is to extend out of the back cover to drive the points and distributor. Not in the picture is the oil line that connects the top of the oil pump to the engine.|
OK! I finally got a little work done on the oil pan. Shown here is the latest version. I think I'm getting close to having a working part here. The only thing that I forgot on this one is the dip stick hole, and I think I can work something out. Click the picture to see The Evolution of the Oil Pan
Here is a picture of the oil pump disassembled. The gears are some that I found on an old computer printer, they are 3/8 inch across. The tubing is 1/8 inch O. D. There is a regulator in the cover. The pump design is from Strictly I.C. Vol.10 No.56 The pump was made from a piece of 1 inch dia. brass rod.
|Here is a picture of the crankcase showing the oil channels. The main oil channel runs the length of the crankcase and is a piece of 1/8 inch brass tubing that was put in the mold before casting. I Thought long and hard before I figured a way to get that oil channel in there.|
Here are some pics of the crankshaft under construction. The first pic is the steel bar that it is made from. This bar is 12 inches long, 1 1/2 inches wide, and 1/2 inch thick.
The next pic shows the rod journals turned and the markings where the excess steel will be cut out.
|This pic shows a close-up of the rod journals. They are not very well finished. This is supposed to be a preliminary part. The real part will be made later when more of the engine is solidly defined.|
|Shown here is the completed crankshaft|
Here is the crankcase with the bearing caps installed with the bearings. not shown is the left half of the crankcase, which has been cast, machined, and the holes drilled for screwing the two sides together.
OK, it is not much yet, but you have to start some where.
The crankcase has been cast and machined except for the screw holes and the crank shaft bearings. I think that the casting turned out pretty good. This is only one half of the crankcase. The other is yet to be cast. The logo came out looking good too.
I had to cast 3 of these before I got an acceptable one. I don't know how to set the cores into the mold to get the exact placement needed. If they are off just a little bit (1/8 inch) the casting is useless.
I have some small core prints on the pattern, but they are mostly marks and they don't match the cores to well. This is something that I need to fix (on the patterns).
|I have done some drawing and managed to draw a composite drawing of the engine, a view from the front end. Click the image for a full size drawing.|
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