Dick,
All my Carter float less carbs had adjustable needle valves.
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Here's a question.
What type and pitch of prop will this monster pull? Ron?
This is fun to watch.
Tim
John
Yes they all have adjustable needles, however the loop had a jet hole drilled into the tower directly across from the adjustable needle. This kept the adjustment in the 1 1/2 turn range. That jet (.0625) hole was the difference in the fuel demand of the looper to the deflecter.
Everyone missed one point here. J-Dub has been in regular contact with Rich Fuchslin. Now maybe I am biased here, but I think Rich has a pretty good handle on making a 6 cylinder run, either the Merc or his big looper.
Joe
Your point is well taken!
However, I don't think anyone who has contributed here would ever discount anything Rich has to say. He can put his record up against anyone and not take a back seat.
We ALL want J-Dub to succeed and he couldn't have a better mentor than Rich Fuchslin!
Conversion of Float-type Carter N carburetor to Floatless Design for use with Methanol Fuel
(Please note: Always use sufficient protective safety glasses while performing machining operations such as described here.)
The process outlined in this document was created to assist the user in converting a float-type Carter N carburetor to a floatless model for improved metering stability in the high engine speed, high vibration environment of a 6-cylinder loop-charged racing motor built by Quincy Welding. It is assumed that one starts with a float-type carb that already is already set up for use with methanol fuel. However, some key carburetor specs are provided to enable verifying that alcohol compatible calibration parameters are correct. The process outlined herein is based on dimensions from two well-known Quincy Loopers.
These motors were selected to hopefully lend credibility to the process. The first step is to remove the float and all float valve parts. On all carburetors studied, the floor of the fuel bowl was spot-faced only enough to clean up a flat area big enough for the standpipe to seat on. The locations of the standpipe must be selected so the standpipe doesn't interfere with the main well of the carburetor and so the spotface doesn't run deeply into the bowl side radius.
Pictures are provided to indicate locations used for standpipes on a 6-cylinder Looper application.
A tap-drill hole the same size as the standpipe ID was bored through the float bowl floor in the center of the spot-faced area. That hole was then tapped (deeply) up through the bowl bottom with a 1/8 NPT that is square with the mounting surface of the bowl. It should be done on a milling machine or drill press chuck (i.e., NOT aligned by hand but hand rotating
the tool chuck is OK) with the bowl held flat, upside-down on the machine bed plate to assure squareness. The depth of the thread is correct when a standard male 1/8 NPT fitting can be screwed almost all the way into the tapped hole. This provides the maximum possible thread length protruding through on the inside of the bowl. Consideration must also be made to have the hose barb oriented properly when the carburetor is on the motor such that a fuel return line can be installed.
The standpipes are made from 5/8 inch aluminum bar stock of a good alloy like 6061 for ease of tapping and for good thread strength. Squareness of the ends with the centerline of the standpipe is essential so this should be done with the part and tap chucked in a lathe. The center bore end is finished with a 0.1 inch radius at the top, probably to minimize any foaming of the "overflow" alcohol as it spills into the standpipe. The center bore is tapped at the bottom with a 1/8 NPT. Again, squareness of this tapped hole with the bottom face of the standpipe is critical for sealing so do it on a milling machine or drill press with the part clamped securely in a pin vise that can hold the part vertically (i.e., one with a V-notch cut vertically in one of the jaw faces or clamp with a separate V-block). The standpipe is held in place in the float bowl by screwing a 1/8 NPT 90 degree male elbow with a 5/16 inch hose barb into the float bowl and then screwing the standpipe down tightly on the pipe threads that are sticking up through the bottom of the float bowl.
A pair of pliers must be used to grasp the outside of the standpipe to tighten it in place. Special care must be taken so as not to crush or distort the inside diameter of the standpipe during this process. All of the elbows found on these carburetors were plated steel but I am sure that brass fittings would prove suitable. Adjusting the tap depth in the standpipe may be necessary to ensure sufficient thread tightness when the standpipe bottoms on the float bowl. I don't know what sealer was used by Quincy Welding but I would recommend use of a product like "Loctite" to achieve a sealed, permanent assembly. Make sure the parts are cleaned before final assembly with the sealer.
Data from Inspection of Wayne Walgrave's 6-Cylinder F-Looper (XF41)
Built in 1971
Float bowl standpipe dimensions" (measurements on two of the three original Carter N carbs were exactly the same... the third original carb was not measured)
Standpipe ID = 0.3598 inch (23/64 drill)
Standpipe height from top to spotface on carb float bowl floor = 0.785 inch
Carburetor specs:
High Speed Nozzle ID = 0.1695 inch (#16 drill)
Orifice size between HS needle valve and main well = 0.1405 inch (#28 drill)
From Inspection of Jerry Waldman's 4-Cylinder C-Looper (FC84)
Float bowl standpipe dimensions" on top carburetor (bowl is also modified for compatibility with Mercury distributor: bottom carb not measured)
Standpipe ID = 0.3598 inch (23/64 drill)
Standpipe height from top to spotface on carb float bowl floor = 0.788 inch
Carburetor specs:
High Speed Nozzle ID = 0.1695 inch (#16 drill)
Orifice size between HS needle valve and main well = 0.1470 inch (#26 drill)
If you have any questions about this process, please contact Mark Suter at (989) 634-8822 or
mhsuter@invisalink.net.
M. Suter/1-25-2012
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I'd like to add a couple notes of my own.
As Frank Volker mentioned in a previous post, the high speed nozzle, aka dump tube, position in the venturi of a carburetor on a Looper with a Carter carb is indeed highly critical. As Chris and I were finishing up the development of the Loopers and moving on to the next generation Z engine, we experimented considerably with the height adjustment of the nozzle on a Carter carburetor on an A Looper. Remembering now what we attempted to do then, was to find the best position that lead to the most usable and balanced range of fuel distribution with an obviously difficult framework to work within, ie in engineering terms, what some consider to be the torturous path that the diametrically opposed internal reed valve of the Mercury design was at times during it's inconsistent performance at high engine speeds. If it were me, I would only attempt those changes on a dyno, never on a race boat out on the water.
A special thanks to Mark Suter and everyone else that has contributed to this thread.
Regards,
Paul
I measured the distance from the center of the float bowl to the center of the overflow standpipe on the two original Carter carburetors that came off the Walgrave 6-cylinder Looper and both were 3/4 inch.
What an honor! And I mean honor! I go to the national meeting in Chicago, come home and have a 28 screws removed from my foot, to finally get a chance to get online to see this UNBELIEVABLE support from all of you racing legends! Wow...Very flattering.
So here is the plan: The path of least resistance as well as past success's is to convert these to floatless carbs. All of these offers to use or copy peoples parts is very much appreciated. However my Dad has a couple floatless carbs to review to build new stems. Also he has been a machinist since he turned the pulleys on the Mayflower and also has built them in the past.
Once we complete this we will get over to Ken's place and piss his neighbors off with the dyno. Then we will run it on Howards 1976 KR Desilva running a 14:15 Komato unit and a 7.5" X 15" four blade, should run about 95mph @ 9000rpm. Then we'll try the hydro.
Thank you all for all your help and support! Now the pressure is on me to get'r done!
J-Dub
All of us are pulling HARD for you!
Glad you've healed enough to make it through security at the airport
Ever since someone posted years ago on how fast a Quincy 6 will go... I remember Gene saying nobody has ever really held one on long enough to find out. With the boats a little more advanced today, I think the 130 MPH mark is not out of the question on a hydro. I would LOVE to find out how fast one goes.
And Gene, as a Mod guy, if you showed up and played your 6 Cyl music, I would tune into it no matter where i was standing. There is no finer song than The Singing Six. Remember, a LOT of the mod guys are old Alky guys... ;)
Hope to see you in Quincy this year if the water comes back.
J Dub, keep up your hard work. I have faith in you that it will run.