I have just finished hours of burring, filing and sanding on the last two remaining pieces, the bellhousing and the timing cover. I was told by a friend of mine that it would be a shame to remove all the tool marks from the bellhousing for the fact that it showed all the machining steps to finish it but although he had a point it just wouldn't fit the rest of the engine. The hardest part was finishing the inside. I probably should have made the steps about half the increments that they were. Nevertheless we a lot of filing I got it smooth.
I wasn't until I viewed the pictures that I saw the layout bluing in a couple of the mounting hole counterbores.
It's been so long since I posted and I have completed so many more parts that I really don't know where to start. I apologize for not doing regular updates but as you all know there is only so much time.
We last finished off with the hand work on some of the major components, so I'll try to pick up from there.
The internal parts, rods, pistons, valves and lifter were made and fitted. The rods are made from steel with bronze split inserts. The pistons are aluminum and will have 3 rings, 2 compression and 1 oil control.
To make the bearing inserts I took a different approach than in my previous engines. For them I made up 2 pieces of stock and soft soldered them together. This was then mounted in a 4 jaw chuck and each insert was bored and turned. The inserts were then melted apart.
For this engine I turned the bearings in one piece and split them with a .010 slitting saw. This will leave a slight gap but not enough to affect the performance of the engine. The only other way would be to make a die and form some type of soft material.
For splitting the inserts I made up a fixture that was turned to a little less than the bore on the bushing. The fixture has a small clamp that holds the bearing in place for splitting. To put the oil and pin locating holes into the inserts I rotated the fixture and clamped an extra piece of bearing insert to it. This was indicated flat. The usable inserts were then held tightly against the shoulder on the fixture and against the other bearing surface for drilling.
The valves are made from stainless steel. The lifters are made from drill rod and hardened. On a flathead engine the lifters and springs are down in the cavity in the center of the block. The lifters have an adjusting screw that is locked in place with a set screw. Once assembled the set screw can't be accesses to each mating valve and liter was adjusted to the proper clearance before assembly. Each assembly would need to be compressed so that the tiny E clips could be snapped onto the tips of the valves so a valve spring compressing tool needed to be made.
The water pumps, one on each side of the block, are castings on the full sized engine. They take water in from the bottom and it passes through the body of the pump up to the impeller and into the block. To make the pumps for this engine I had to make them in two pieces, much like the heads. This was to get the water passage inside. The pump bodies are aluminum and a bronze impeller is pressed onto a stainless shaft which rides on 2 sealed ball bearings. At the water side of the shaft is a small O ring which will seal the shaft from leakage.
The carburetors are made to somewhat resemble a Stromberg 97. They will be of the air bleed type but outwardly will have the proper appearance. When I sat at the drawing board (computer) and drew up the engine I didn't have many hard dimensions to go by so a lot of the parts and pieces were scaled by eye and drawn accordingly. Such was the case with the carbs. The original carbs looked good on paper but when I set them on top of the engine they just looked a little too small so I revised the drawings and whittled out another pair. Although these look a tad too big they are closer than the first set. To top off the carbs I had the option of several different types of air inlets or air cleaners. I opted for the polished helmet style found on many hot rods. Along with the new carb dimensions I had to modify the flange on the intake manifold to accept the new size. To accomplish this I made an adapter plate that went over the one machined onto the manifold. This is held in place by some 2-56 screws.
The fan was was made from sheet aluminum. I cut a pattern from the drawing as a rough guide for sawing and then cleaned up the edges of the blades by milling and filing. A fixture was made to press the stiffening rib into the center. The fixture is a male and female with a groove cut in one side to accept a piece of drill rod. The other side had a larger groove milled with a ball mill to give clearance for the drill rod plus the thickness of the material. Once the beading was pressed into the blades then were twisted to the proper angle. The pulley is machined for ball bearings and rides on the end of the fan bracket seen in a previous picture of the generator.
The exhaust manifolds are made from .375 O.D. stainless tubing. It is grade 316L and has a wall thickness of .035. I had made a specific tubing bender when I was building the V-twin so I used this as a base for the flathead. I needed a tighter bend, from 1.3 radius to .90. A new forming die and follower shoe had to be made. I bought a 3 feet long piece figuring that would be enough for practice and completion. I had some other .375 stainless tubing but with a .050 wall. I tried the bender out on this first and to my surprise it formed quite nicely. With the experiments out of the way I started making the mounting flanges. A piece of 303 was squared up and 8 flanges were cut off. A stop was put on the vise so the holes would all repeat on each piece.
With these finished it was time to bend the first pipe. I left a little extra on both ends for safety sake. It came out well. I then clamped it in the vise between 2 small V-blocks, rotated it to the proper angle and then using a slitting saw cut the angle that meets the flange. Three other short pipes were also cut.
To assemble the tubes I needed a holding and locating fixture. I started with a bar of CRS and tapped 4 holes representing the port spacing. Into these threaded holes I screwed 4 studs with a large flange on the tops. The whole fixture was then put in the mill and everything was skimmed off flush. The mounting holes corresponding to the top of the block were then drilled and tapped.
I then mounted a flange on each post and tightened them with 2-56 socket head screws. The main runner was clamped into the locating fixture and twisted and slid until it was lined up with the number 1 flange. Everything was tightened down. The other 3 curved pipes were then hand fitted to the runner and flanges. This would require a half round on one end to fit the main runner and an angle on the other end to match up to the flange. Once I had them all fitted I drew a line around them with a fine permanent marker. Each pipe was removed and another line was drawn inside the first. This would be the guide for cutting the port hole in the main runner. Once finished all the pipes and flanges were assembled and fluxed in preparation for silver soldering. Using my oxy-cetylene torch with a small tip and 56% silver solder I brazed the whole thing together. When I disassembled it I found that it had warped just the smallest amount so on the second pipe I did the main runner first and when it cooled I added the other three. That seemed to work much better.
The final shots of the exhaust manifold build show the silver solder, flux and my 'Little Torch' which I used for touching up a few places I missed with the big torch.
And finally the pipe cleaned up, polished and mounted to the block.
I now have both exhaust manifolds finished. Along with them I finished the replica fuel pump along with a glass sediment bowl cut from the bottom of a test tube. As much as I like chopping away at metal I just couldn't force myself to replicate the fuel pump from one piece so it's all made from individual pieces and screwed together.
I'm getting down to the last remaining parts on the engine.
Once I found the one-way bearing as a starting device I have put it on all my engines. The small engines I use a .375 diameter and the bigger engines I use a .500 diameter bearing. Rather than just mount a disc to the flywheel and to go along with all the other, "it looks like starter, or generator", I opted to make what looks like a clutch pressure plate. It's made in two pieces, the outer housing and the disc with the boss for the starter bearing. The outer housing pinches the disc against the flywheel by .002 but just to be sure it doesn't spin under load I used three 5-40 bolts that are positioned like the trunnion bolts on the full sized clutch.
The second set of pictures are of the dipstick flange, tube and stick. I'm always saving bits and pieces for possible use in my model work and I happened to have some stainless steel strips that go down the side of a windshield wiper blade. They are kind of like a spring steel but can be machined to the needed width. I cut a strip .104 wide, rolled the top and then machined a cap to go onto the top of the tube. The cap was drilled .106 diameter and then counter bored .156 diameter to go over the tube. The outside diameter has a small step at the top which I slotted with a slitting saw. This allowed the strip to slide through. I then positioned it and silver soldered it in place.
Just a quick update on the engine progress. Piston rings were made and installed. Engine was assembled with oil in the pan and run by means of the lathe to loosen things up and check for oil pressure. Everything seems to work as it should.
I have two large pieces yet to complete, the base and radiator. There are also a handful of small components remaining, carb parts, throttle linkages, brackets, wire looms etc.
Having started on this project last August I am now over the one year mark with a couple of months left to completion. Not counting the hours of design and drawing I will be in the area of 1600-1800 hours.
It's been awhile but I have been making progress. Since my last posting I have made quite a few bits and pieces. These were mostly cosmetic parts, starter, generator etc. as the internals are complete. The original intent, like my 302 V-8, was to create a running engine that cosmetically would replicate the full sized engine. These parts add to that look but are non functional, well the generator tightens the belt to operate the water pump. I also finished up the carb linkage and a miniature Moon racing type gas pedal.