A flathead V-8 engine

This manifold will resemble a dual plane type. For those not familiar with this engine terminology I will explain.

When engines only had 4 cylinders to feed the intake manifolds weren't that long so getting the proper mixture to all cylinders wasn't too difficult but as cylinder counts and engine configurations changed some of the cylinders were starved for fuel. It was first hard enough to get the charge out to the enc cylinders but also with the intake cycles of different cylinders the charge would have to travel in one direction then immediately reverse to feed a different cylinder. To alleviate this problem, at leas on V-8 engines the dual plane manifold was designed. With 2 and 4 barrel carburetors one side of the carb feeds only 4 cylinders, 2 close on one bank and 2 out on the ends on the other bank. This made the distribution more even so each cylinder in the engine would run the same as another, or close. There are single plane manifolds for high performance use. This consists of a single plenum (chamber) that all the cylinders feed from This is used for higher rpm's where the velocities could be maintained for adequate fuel distribution.

I started cutting the area around which will eventually form the carb bases. From there the different levels and runners were shaped. Once again a tooling change was required so the vise came off and the angle table went back up.
Actually I do have room on the mill table for both but I don't have room to tighten the hold down nuts on the angle table because they are recessed under the table and I can't get a wrench on them.
The angle was set for the outer ends. This would match the inside port runner. Each side was set up and cut.

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On the front of the flathead manifold there is a projection on the casting to mount the generator. On the back of this bracket is a tapped boss that the generator bracket is bolted to and two angled supporting ribs. Close to this bracket is also the hollow boss that the breather tube goes into. Due to the tight constraints of milling in this area I couldn't get any good pictures. The manifold was set at one angle then another, walls stepped off and radii developed. Once they were all cut close I had to go back and recut each area to the finished dimension.
There's still along way to go but at least it's looking like an intake manifold.
gbritnell

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Gentlemen,
The intake manifold is finished, at least all the shape. All that's left to do is solder the cover plates over the runners when the soldering kit arrives. I finished up all the small machining jobs, the generator bracket, cutting the angle on the carb bases and drilling the carb mounting holes. It was then on to the burrs, stones, files and emery cloth. I will take more pictures when I do the soldering but for now here's where we're at.
gbritnell

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Superb! A masterclass in producing a masterpiece....bow.gifbow.gif

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Bernard

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To finish the manifold machining I needed to make the patch plates to cover the runners. The runners were machined 'to the numbers' when I did them so I took measurements and both cavities were within .001 of each other. The patch plates needed to be .078 thick and having nothing that thickness I cut out a couple of pieces of .25 stock and first cleaned up one side. The pieces were then flipped and the .078 thickness was machined leaving a frame around the edge to support the plate while clamped in the vise.
I made a machining chart and started cutting the required shape, at first opening up the center windows so I wouldn't get any chatter on the side walls. I was using a .125 end mill to do the profiling.

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With the center area finished I did the outer sides of the legs. The piece was then taken to the bandsaw and the frame area was cut away. I measured all the dimensions of the part and found that I was +.003-.004, which was fine as I allowed .002 when I made the cutting chart. Better big than small. The next step was to file the overall dimensions first. This was followed by filing each leg to the proper size.
The inside corners were then squared up and a .125 radius was filed on two of the outer corners. I slowly fitted each leg until the pieces slid snugly into the cavity. With the fitting done I sketched the inner half of the port radius on each leg and burred and filed it to size. One down one to go.
The second piece was practically a carbon copy of the first, file and fit.
All that remains is to lay a bead of solder over the joint areas and then skim mill the bottom flat. I haven't received the aluminum solder kit yet so that will have to wait.
gbritnell

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Gentlemen,
The next part of the build series is the crankshaft. Normally with most builders this is a dreaded project. Over the years I have constructed cranks by many procedures, fabricating, silver soldering, pinning and cutting from solid. I have found that there is a place for each of these practices but for multiple throw cranks I much prefer making from solid. My metal of choice is 1144 stressproof steel. It cuts very easily and the biggest asset is it doesn't warp or should I say the distortion when machining is negligible.
That being said I started with a bar 2.00 dia. and 8.00 inches long. Using a steady rest I center drilled both ends then cleaned up the O.D. to near the finished size. The ends were then turned down leaving enough stock to cut flats that would be used to locate the part in the fixture blocks for offset turning of the crank pins.
gbritnell

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While that blank was having the locating flats cut on the ends I also milled out the excess stock from the main bearing locations. I have found over the years that it's much easier to mill the stock out rather than trying to plunge in with a necking tool on the lathe. I rotated the part while milling to further reduce the amount of stock to be turned. From the mill the part went to the lathe with one end being chucked in the four jaw chuck and indicated true while the outboard end was supported with a live center.
The tool is used for turning the journals is one made from a .500 high speed blank. It took a lot of grinding to make it so I only use it for crankshaft work. The sides are ground lower than the front edge for clearance and the tip is bifurcated as to lessen the loading on the tip while cutting. To get the tool square I set it against the side of a true surface and then run an indicator across the tip, tapping it slightly to get both tips parallel with the lathe axis.

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