|PUTTING IT ALL TOGETHER Three Easy pieces* |
The Manifolds My goal, like the American Indian, was to use as many parts as possible from the buffalo (or in this case the Champion motor) being butchered. This would assure that anyone could do the same thing. Too often in articles in car magazines you will read along saying “I can do that” to yourself until you come up against the brick wall of “now use factory tool J-619712” or “we then went over to Bio-Cryo-Techno-Wiz-Bang Automotive on Labrea in Los Angeles” to have a prototype hyphenization carbueration coagulator installed (for free), at which time you swear and stop reading….NO! I was determined to do this with only a wire feed welder, the stock intake/exhaust manifold, a grinder, a drill and a hacksaw. I first hacked,drilled, chiseled and ground on the intake/exhaust manifold just above the level of the set-screw in the side of the exhaust manifold. The cut was made just below the “floor” of the intake which normally was getting heated by exhaust gases. After getting it off I was able to work on it as two separate systems.
Exhaust/Turbo flange: After grinding the top flat, I bent a _ inch strap in roughly a square shape, grinding parts so that it would slip over the square cross section at the “cut off” point where the two manifolds connect. I then made a flange that would bolt to the exhaust intake of the turbo using studs. I am told that bolts used here should not really be high grade due to the expanding and contracting going on. I made a copper gasket of sheet copper to echo the shape of the flange. I made a plate of 1/8 inch steel to cover the exhaust header flange and remove the heat riser valve, covering that too. These two parts of the exhaust manifold might be used later as an exhaust bypass. The turbo flange needs to be oriented so that the turbo is in the appropriate position for the exhaust and for the induction system. The oil inlet should be high (I made mine directly on top) with the oil outlet low for best drainage (in my case, into the side of the oil pan above the oil level). In my case, the exhaust will be to the bow and the induction will be to the stern. Question: Should I restrict the volume of my exhaust manifold further with a “filler” attached to the cover plate?
The Intake Manifold: To make this, I needed three thick flanges to coincide with the siamese intake ports. I cut the flanges off the old cast iron manifolds and ground them flat. To make room for the turbo to sit roughly where the carb used to be, I had to have runners that came 90 degrees pretty quickly just before they entered into the motor. After a lot of thinking, I settled on fashioning these angles by careful cutting of some square tubing. The flanges weld on the side of the tubing. The runners need to be long enough to rise (when added to the height of the 2 x 4 x 18 inch plenum) above the height of the head studs, allowing the head to be put on the motor and taken off without taking the whole thing apart. I fretted over the plenum. It is big with not especially a streamlined shape. A lot is made of air flow and gas puddling in intake manifolds, but I think that some of it becomes less important when one has a few atmospheres of positive pressure. I did hang a piece of cut angle iron over the middle intake runner to “disperse” the gases slightly (theoretically keeping the center two cylinders from running relatively richer than the others). I welded nuts over two holes I drilled in the manifold (as location for sensors or injectors later). Finally I had both pieces sandblasted then painted them with high temperature (1500 degree) aluminum paint. The whole unit bolted together makes a rather compact package. How much gating is necessary remains to be seen. Quick throttle response is important to me. Quick spool up from the small turbo and short exhaust set up is expected. The long-legged intake manifold may hurt the spool up (I may inject compressed air saved from the waste gate to help this problem, but that’s another story………….).
1)Should I further restrict the volume of the plenum with a filler?
2) Do I really need the “disperser” beneath the carb? I’m told that the disperser is a good idea, and that optimally, I should have made the manifold a rounded cross-section with some length beyond the end runners.
The Carb Used: One probably doesn’t need a huge carb for this. I bought four at $5.00 to $40.00 each and had two original “WE ” Carters, one of which I have re-built. Besides the Carters, I have a Holley 1904 single “economy” carb, a 60’s Carter dual carb, a later 60’s Holley dual carb and a Weber dual carb from a BMW 2002. The intake manifold was built with a removable top plate which will easily allow me to try each carb without major surgery. The carb must be “pressurizable” or must be entirely enclosed in a box (more necessary at higher boosts). To do this requires modifying the carb so that all the “holes” (like at throttle shafts) to the outside or through the float chamber are at a pressure “against” outward egress of fuel/mixture. This is sometimes a non-issue at boost less than 10 lbs and with some carbs. I added air passages to the throttle shaft of a “WE” carb to achieve air bearings/seals with air pressure provided from above the ventures. On both the WE and the Holley I filled the floats with polyurethane foam (and epoxied the holes I drilled shut) to keep them from collapsing under pressure. My first choice will be the 1904 Holley. It is from a 196 cubic inch Scout slant 4 cylinder motor. It is simple and parts should be easy to get. It is a little bigger in capacity than the original carburetor. It was also used on early 60’s Ford six cylinder motors up to about 225 cubic inches. The Holley carburetor was new in the box for $40.00 and useless to anyone else. The WE carburetor is just big enough for my plans but difficult to modify jets. It seems to have a needle arrangement. I need to explore this more. The Carter and Holley dual carbs are possible but need restoration and are overall more complex. The Weber is sexy, but maybe too small – again I need to study it more. Besides filling the Holley float with foam, I replaced the float chamber breather hole with a nipple which could be tubed up to the compressor outlet. I’m told that the single Holley may be marginal and that a better performance choice might be a carb between 350 and 600 cfm. My used Holley two-barrel turns out to be from a 73′ Dodge truck with either a 360″ or 400″ motor. It is called a “6575” and is 330 cfm. I’ll get this ready in reserve, and get running with the single carb Holley for now. The Carb situation Holley 2 barrel 6575 330 cfm Carter 2 barrel
Question:1) Is the float chamber connection necessary or could it just be blocked off? 2) Am I kidding myself in thinking that the Holley 1904 is adequate? See above. Any hints on how to rejet it?
The Fuel pump: My first thought was to use an electric pump, but came across some info in an old book about pressurizing the “other” side of the diaphragm of a mechanical pump with a connection off the compresser outlet. I then saw this mentioned in a recent “Real Safaris”. I have determined that it is feasable with the Stude mechanical pump and fabricated a nipple for the connection at the site of the breather hole. I may need to install an auxiliary pump activated by a pressure switch to provide enough pressure to overcome the boost pressure in the float-bowl. Is there a common pressure switch that I could find? (ie: brake switch?)
Further air “processing”: You may note from the pictures that there is a 3 inch piece of tube just above the carb. This section is in place to give some “wiggle” room should I change carbs, allow a place to inject air or water into the system to decrease lag or prevent detonation. It will initially act as an air “straightener”.
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