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A flathead V-8 engine

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gbritnell

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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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gbritnell

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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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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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Dranreb

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

thanx.gif

Bernard

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gbritnell

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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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gbritnell

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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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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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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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gbritnell

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With the main journals rough turned, I left .008 for the inevitable, the blank went back to the mill to rough out the crankpin areas. This was done in three steps, the deepest cut and then the two side cuts leaving a somewhat square area to be turned.

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jumps4

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what a great build, thanks for posting
Steve
 

gbritnell

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Two fixture blocks were machined from aluminum. The one for the chuck end has a large diameter to accommodate the flywheel flange and the one for the tailstock has a smaller bored hole to fit over the front diameter on the shaft. The tailstock fixture also has a center drilled hole to locate the live center Both blocks are drilled and tapped for set screws that are used to locate on the flats milled on the ends of the crank. The set screws (grub screws) are ground flat to more accurately locate on the flats.
The headstock end was mounted in the four jaw chuck and indicated to get the proper offset for turning the crankpins. (1.125) The blank was then inserted and tightened, rocking back and forth as the screw was tightened to centrally locate the stock. The tailstock fixture was then slid on and tightened in the same manner. The live center was then inserted and tightened just enough to hole the blank in place.

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gbritnell

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The crank was then mounted between centers and the remaining stock was cut from the main journals. The front diameters were finished as was the flywheel flange. For most of my engines I have used a key and set screw to hold the flywheels in place but for this engine I thought a bolt flange would present less loosening problems while running

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Eddyde

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Wow what an amazing build!!! Do you have any use planned for it or just display?
 

gbritnell

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Hi Eddy,
I have no particular use in mind. Every year I come up with a project to get me through the winter. This year it's this flathead engine. I enjoy machining and building things whether engines or other mechanical items.
I have a 302 V-8 along with a T-5 transmission and 9" Ford differential. The plan was to build a complete chassis but that's been put aside for the time being.
gbritnell
 

gbritnell

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Ok, we left off with the turning complete on the crank so the next step was to start cutting the extra stock away from the counterweights. For this a fixture would be needed. I already had a flat fixture plate that had been used for machining the block so I made up 5 pedestals to hold the crank. These were milled to size, tapped and drilled then they got a .751 hole bored in them to fit the main journals, after which they were just split open on the bandsaw.
The fixture plate was clamped to the mill table and indicated parallel with the X axis. The crank was then clamped in place. To simplify setup for each throw I set up an adjustable parallel to go under the horizontal throw journals. This put the other throw in the vertical position to cut the counterweight.
After all the the counterweights were cut I tilted the mill head on 15 degrees to cut the extra stock from the top of each throw at the crank pin.

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gbritnell

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This is what the crank looks like up to now. I am copying a full sized crank so that's why the counterweights look like they do.

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gbritnell

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The next operation was to drill all the oil holes from the throws to the main journals. These are .062 diameter and a standard jobbers length drill will just make it through by holding about .25o of the shank.
I set up my angle table for this operation and indicated it true both for parallel and angularity. The fixture plate was then mounted, indicated and clamped.
The crank was clamped in place and I used the same procedure for aligning the throws as I did when I machined the counterweights. I then found the center of the crank with an edge finder and picked up the scribed layout line for the hole center.
The hole were first drilled with a #2 center drill which gave me a .062 pilot hole. I then proceeded to peck drill with the drill going down about .125 at a time and pulling it out to clear the chips. No need to have something nasty happen at this point.
When I saw bits of aluminum come out of the hole I knew I was through. All in all it wasn't as bad as I thought it was going to be. I used a brand new drill just to be sure.
gbritnell

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gbritnell

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Here are the finished holes. All that's left to do is chamfer the edges.
gbritnell

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gbritnell

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Now the easy but tedious part, radiusing all the corners and edges, filing and polishing.
 

gbritnell

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Gentlemen,
The crank is finished. I spent the better part of today, burring, filing and polishing but it was completed without incident, oh yes and tweezing little slivers of steel out of my fingers. I set it up on blocks on my photo shooting stand and took picss of it rotated in different positions. On to the connecting rods.
gbritnell

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FOMOGO

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I put together quite a few full size engines and I'm wondering if there is a procedure for balancing the rotating assembly, or does the size of this make it pretty much a non issue? Very nice work, and I would think it's got to be much easier on the back than lugging around the Ford FE cranks and blocks I'm ussually working with. Mike
 

gbritnell

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Hi Mike,
On some of my cranks I have no counterweights, on others I have full counterweights on each throw. The last two engines I built I replicated the shape of the full sized crank. I think with this scale it's pretty much of a non entity. They could be static balanced but although I know how a full sized crank is dynamically balanced it would be hard to replicate in this small scale.
Thanks for watching,
gbritnell
 

gbritnell

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With all the major parts machined it's time to start picking away at all the small bits and pieces.
I turned up all the main bearing inserts from bearing bronze rod. They were split and fitted to the crank and block. The caps were drilled for stop pins to keep the inserts from spinning. The inserts were drilled to match the oil passage in the block.
I turned the flywheel from 12L14 steel (4.25 dia.) and drilled and reamed the mounting holes to match the crankshaft.
I turned the blanks for the timing gears, steel for the cam and brass for the crank. The cam gear will be pressed on with no actual way to align it for timing so the crank gear will have 4-.062 key slots, one lined up with a tooth, one lined up between two teeth, one a 1/4 between the root and tip and the last tooth 1/4 on the other side of the root. This will allow me to set the cam timing within 3 crank degrees which will be close enough.
The gears are 32 D.P. and I just happen to have a set of involute cutters that fit the number of teeth I needed.
The teeth were cut on the cam gear and then it was set up on the rotary table to have some slots milled into it.
gbritnell

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gbritnell

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Gentlemen,
Well I'm back from Cabin Fever so it's time to get back to work. The first thing I wanted to do was finish the block. I need to do this so that I can fit the lifters, valves and such so that I can move on to the other parts.

I had the liners machined prior to Cabin Fever so the first think I did was to wash the block with hot soapy water to remove any oil and swarf that might be in the water jacket area. I made up a drift plug that slipped inside the liners so that I could tap them in place. I only went for a .0015 press fit both at the top and bottom. This was augmented with Loctite. The block was warmed with a heat gun and the liners were tapped in place until the shoulder on the sleeve bottomed out. I left the sleeves about .015 long so they could be trimmed flush with the head deck afterwards.

I turned up the valve guides from bronze here again trying to maintain a .0015 press fit. The valve stem diameter is .09375. A specially formed tool was made to fit over the tapered end of the guide so that they could be tapped in place. Once I had all the guides inserted I made and pressed in the valve seats. These were made from 1144 steel.

I had a seat cutting tool in my drawer full of specialty cutters but the one with the .094 guide was just a little bit small so I had to make another from drill rod.
Once the tool was made the seats were all cut by lightly turning the tool by hand and just shaving off the metal.

The angle table was then set up on the mill and the block mounted to the original fixture plate. The angle was set for 45 degrees and the table and fixture plate were adjusted until I got a -0- reading in both X and Y directions. The tops of the liners were then trimmed flush with the head deck.

The next step was to get out all the burrs, mounted stones and files to clean up all the machining marks. I spent about a day doing this. The final process was to hone all the bores to get them true and to size. I had mentioned earlier that I had to make my own hone due to the fact that the bore is an odd size (.832 dia.) This is really a messy job and once finished the block had to be washed with solvent and then hot soapy water again.

I can now say that the block is finished.

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