carbking
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Posts posted by carbking
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Rick - I have driven over 1 and 1/2 million miles with points and condenser ignition. I walked once, when a fiber timing gear broke. With less than 100,000 on electronic ignition units, I have walked 6 times (now I have a cell phone <img src="http://www.aaca.org/ubbthreads/images/graemlins/wink.gif" alt="" />). I will admit to wiring a broken point set together once and limping home at 40 MPH, but at least I didn't walk!
You figure the odds based on the above as to which is the most unreliable!
Jon.
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PackardV8 - will be extremely interested in your report on change in gas mileage. On a different make of car, I removed the factory HEI and replaced it with points and condenser for the same reason, plus the additional reliability of the points and condenser.
Jon.
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The US government publishes an excellent reference on many different alternate fuels, including ethanol. It is not free, and is available from the US government.
As to emissions: if the fuel ratio is held to the "perfect" mixture, ethanol will lower 2 of the 3 CURRENTLY MEASURED EMISSIONS by a scant few percent. However, the MAJOR byproducts of the burning of any alcohol (including ethanol) are aldehydes and acetylaldehydes (remember that nice-smelling frog in 7th grade biology that was pickled in formaldehyde?). We may slightly reduce one problem while introducing another.
As to fuel economy: do the math. Gasoline contains 117600 BTU/gallon. Ethanol contains 67000 BTU/gallon. ANY mixture of gasoline and ethanol will have LESS energy than gasoline. Use the equation 670 E + 1176 (100-E) = effective BTU; where E is the percentage of ethanol. Example: for a 15 percent ethanol mix the equation is [(670 x 15) + (1176 x 85)] = 110,010 BTU or a 6.5 percent decrease in the energy content of the mixture. This is sufficient to require recalibration of carburetors on carbureted engines.
As to reduction of dependance on foreign oil: The latest (that I have seen) government figures show an input of 129,000 BTU to produce ethanol of 100,000 BTU. In other words, give me a dollar and 29 cents; and I will give you back your dollar!!!!!!!!!!!!!!!! Must be the new math, but I fail to understand how using MORE to make LESS reduces our dependance on foreign oil.
It is true that engines may be configured to optimize the increased octane of ethanol TO PRODUCE SOMEWHAT MORE HORSEPOWER than with gasoline by radically increasing both compression and timing; but at the expense of economy. Racers have known this for decades. However, when setting up a carbureted race engine to run on alcohol, we calibrate the carburetor to use 2.2 times the fuel as if the engine were using gasoline.
As to damaging effects on older cars: 15 percent ethanol is not particularly a problem. The older car owner should install a modern paper fuel filter at the carburetor (ethanol tends to "cleanse" gum and varnish from the fuel system); replace any neopreme fuel line with alcohol-resistant fuel line; and in the carburetor replace neopreme accelerator pumps with leather accelerator pumps and polynitrophyll (foam) floats with brass floats. Fuel pumps using diaphragms and carburetors using diaphragms will need the diaphragms replaced more often. If irratic idle and "surging" are experienced, the carburetor will need to be recalibrated. Often, this can be done by raising the fuel level(s) in the bowl(s) by about 1/16 inch above specification. The higher fuel lever in the fuel wells reduces the amount of negative pressure necessary to effect bleedover, thus enrichening the mixture. Try this "redneck" approach before paying a carburetor rebuilder to recalibrate the carburetor.
If possible, avoid the use of ethanol in older vehicles.
Jon.
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Thanks Ron, that does help; however, I believe I will continue to suggest to my customers that, if they plan to have the car judged, consult with the judging authority first.
Jon.
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This issue arises at least weekly, and our standard answer is to contact the judging authority; but, if possible, would like to have an answer posted here.
The issue: die-cast pot metal (zinc alloy) carburetors produced generally in the late 1920's which have deteriorated beyond safe use.
More information: many of the carburetor companies began producing the die-cast carburetors for economy reasons. Often the standard carburetor for the previous year for the same application may have been either brass or brass and cast iron in construction. One of these often is a correct calibration bolt on interchange.
Possible solutions when this issue occurs:
(A) have the original carb recast from aluminum or brass
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substitute an earlier carb for the same engine (see above)© substitute a "period" replacement carb (example - Carter BB-1 series)
(D) substitute a newer, possibly current production replacement carb
The question: from a "points" standpoint, how would a judge deduct points for any or all of the above solutions? Would recasting the original (very expensive) be better than the other solutions (still wrong, because the metal type would be wrong)?
Thanks in advance to any who respond.
Jon.
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A "terrible" idle when cold can be caused by many issues (most of them ignition). Old spark plug wires can accumulate moisture in the insulation and not fire properly until the engine heat dries them; but this is an issue for the electrical gurus.
For the purpose of this post, we will assume the carburetor is the problem.
If the engine runs normally after warming, we can probably assume the idle, off-idle, and main circuits in the carburetor are functioning.
The choke circuit delivers a "richer" mixture to the engine when cold. The choke circuit is one of the most misunderstood in the carburetor, but one of the simpliest circuits. The choke plate closes partially, thus restricting the air and causing a richer mixture to be delivered to the engine.
The choke plate is closed by the choke control coil or spring. This spring can (it seldom does) fatigue, thus not closing the choke plate sufficiently to allow the proper mixture. More likely, a defective choke setting is either a current misadjustment (or a previous one by Dr. Goodpliers - Mr. Goodwrench's evil twin, which damaged the spring). Unless the spring is badly damaged, a fatigued spring can still be made to function until a new one can be acquired. Ignore the factory setting of the "points" on the choke cap and housing. Loosen the screws holding the choke cap. Rotate the throttle to release the choke lockout. Rotate the choke cap until the choke plate is in the open position. Now gently rotate the cap in the proper direction until the choke plate just touches closed. THIS ADJUSTMENT IS TEMPERATURE SENSATIVE! The perfect environment is cold engine, and ambient temperature at 68 degrees F., however doing the adjustment when the ambient is between 65 and 70 degrees F. is close enough.
Now the part that is most misunderstood. The spring does NOT open the choke plate! The choke plate is opened by engine vacuum, as well as pressure on the choke plate by the velocity of inlet air. There is a tiny vacuum passage in the carburetor that winds its way around through the choke housing and behind a vacuum piston attached to the choke shaft inside the choke housing. The engine vacuum will exert a force on the piston which works against the force exerted by the choke spring. Thus when the engine is being cranked by the starter, the choke plate will slightly open, thus allowing sufficient air to start the engine. As the choke spring is heated, it relaxes (bi-metallic spring like the thermostat in your house) the force exerted; thus allowing the engine vacuum to more fully open the choke plate.
The key item here is the vacuum passage. If this passage becomes clogged, THE CHOKE WILL NOT OPERATE PROPERLY causing some to overadjust the cap damaging the spring; others to buy a new cap. If I had a nickel for every choke cap and spring that were needlessly purchased due to a clogged vacuum passage, I would have sufficient funds to purchase the state of Florida and retire!
The function of the choke spring may be tested by removing the choke cap and spring and placing them on your workbench with the spring up. Make a notation on your workbench as to the position of the free end of the spring. Borrow a hair dryer from your wife or girlfriend (not both
) and heat the spring. Make a note of how far the free end of the spring rotates, and compare this distance to the distance necessary to move the choke plate from closed to open.Another item which is a part of the choke circuit is the fast idle cam. This cam has different "steps" which control the idle RPM when the fast idle adjustment screw is in contact with one of the steps. This cam will rotate as the choke plate opens. The rotation changes the height of the steps, and will allow the engine to decrease in RPM as the choke plate opens.
Note that all of the above is accomplished automatically if everything is in correct working order. If the driver "blips" the throttle, the additional air velocity on the choke plate will cause it to open prematurely, thus changing the step of the fast idle cam. When the "blip" ends, the engine will decrease in RPM lower than the temperature will allow, and the idle quality will be poor.
For the system to work correctly, when starting a cold engine; one should push the footfeed to the floor to release the choke lockout AND REMOVE ONE'S FOOT FROM THE FOOTFEED! Starting the engine should then allow the engine to warm and slow to the proper idle.
Jon.
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The "pump discharge check valve" is a small pointed square length of brass located under the pump jet, and has the point down.
The function of this item is to close the opening to the pump nozzles when the footfeed is lifted, allowing fuel to be drawn into the pump well from the bowl. When the foodfeed is depressed, the inlet valve closes, and the pressure from the pump lifts the discharge check valve from its seat, allowing fuel to flow past the valve through the pump jet.
Jon.
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DeSoto Frank - Carter made hundreds of different YF carbs. I posted a listing of those used as replacement for Chevrolet on the Stovebolt forum, if you wish to obtain a listing.
Using a YF for a different application than original could create problems, as the YF was used on engines from the 134 Willys to the 300 Ford. Externally very similiar, internally VERY different. The *&^%$ ethanol IS creating problems for diaphragm type accelerator pumps (as used by the YF) for the owner who only occasionally starts the vehicle.
Far fewer problems are reported by those who drive the vehicle daily.The Rochester B has only 4 screws holding the airhorn onto the bowl (8 would probably have been a good number for the area involved). Warpage of both castings occurs, permitting an internal vacuum leak to the vacuum passage controling the power valve (or economiser valve, depending on ones own scheme of nomenclature) thus allowing this valve to provide fuel enrichment at all times, not just under low vacuum conditions (WOT). In other words, the unit normally runs very rich. For best results, the casting cannot be machined (machining removes the gasket sealing "ridge" and also weakens the casting thus permitting accelerated warpage). To properly rebuild one of these carbs, a special form can be made which will allow pressure to be applied at the warped areas, and the unit then heated in a oven to reverse the warpage (at least for a few years).
The 2 and 4 barrel Rochesters (2G and 4G series) used sufficient screws, and are virtually "bulletproof", VERY reliable carburetors.
And it takes two to argue; since I won't, no fight will be started
Jon.
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Joe - you have mail.
Jon.
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We used the "Master" (we referred to them as "Parker Bros") valves for reliability. Since the Parker Bros valve will maintain a more constant fuel level, fuel economy and performance will be improved, but except in extreme useage, is probably only measurable via instrumentation, not by "seat of the pants".
As to using Stromberg on 1950's GM 6 cylinders:
It is my opinion that Stromberg (the USA company) ALWAYS was in the top 2 or 3 brands of carburetor (these brands would normally change over the years). It would depend on WHICH GM 6 cylinder to which you refer. GM trucks used Zenith carbs (another brand in the top 3 in the 1950's). Pontiac (for the most part) used Carter (the other of the top 3). I would see little benefit in replacing either the Zenith or the Carter (although the more wide-spread use of *&^%$# ethanol is making me have second thoughts about the Carter YF because of the diaphragm accelerator pump!).
However, when replacing ANY original equipment carburetor (by definition, engineering and recommended by the original manufacturer); one must do one's homework in selecting a different carburetor that has the proper airflow and proper fuel curve for the application.
One other thing to consider: the word "best" will have different meanings to different people. My criteria for "street" carburetors, in order, are reliability, performance, and initial cost. For race applications the performance/reliability factors flip-flop. Initial costs (these normally do NOT translate to overall costs) are generally low on my list of considerations. Others may disagree.
But, to maybe answer your question, if I had a 1950's Chevrolet 6 cylinder with a Rochester B, 3 nanoseconds after acquisition of the vehicle, the B would be replaced.
Jon.
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The "Master Float Valve" was produced by a company in Oklahoma called Parker Brothers. It consists of a brass seat with an inverted flare around the orifice, and an aluminum plunger with a flat neopreme washer inserted into a concave aperature in the end of the plunger.
The valve has the following advantances:
(A) the flat washer cannot stick in the orifice
(
since there is no part of the plunger inserted in the orifice, full fuel flow commences immediately when the plunger is off the seat, maintaining a more uniform bowl fuel level© the aluminum plunger does not "magnetize", thus attracting foreign particles
We used thousands of the valves over the years. Unfortunately, the company making the valve is no longer in business. The conventional "needle and seat" fuel valve is what we use today.
Jon.
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While not a desirable situation, it is not uncommon for ANY updraft carburetor with a gravity feed fuel system to leak fuel when the engine is not running. It should NOT leak while the engine is running; and the fuel shut-off valve should be fully open when the engine is running.
If the carburetor leaks while running:
(A) check the fuel delivery system. If an electric pump is used <span style="font-weight: bold">THE PUMP MUST BE A SELF-REGULATED LOW PRESSURE PUMP!</span> The dial type regulators which we have tested are quite useful if one has a strong arm and a rabbit problem in the garden! If a vacuum tank is used, make sure that the vacuum tank is not being pressurized, delivering too much fuel to the carburetor.
(
check the carburetor float. Brass floats may be tested by submersion in hot water. If there are leaks, there will be bubbles.© check the float adjustment
(D) check the carburetor casting for cracks. A cracked brass carburetor is rare, but it does happen. More common with the late '20's zinc alloy carburetors.
(E) If, and only if, all of the above is normal, put a kit including a new fuel valve in the carburetor.
Jon.
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Two other things to consider are the fuel valve and the float in the carburetor itself.
The orifice in the fuel valve is a number 19 drill size (0.166 inch) because of the gravity feed. I have seen some aftermarket fuel valves that would allow the engine to purr at idle but would run the bowl dry at highway speed.
Also consider the float arrangement. Johnson used absolutely the most Rube Goldberg float arrangement I have ever seen in any carburetor, but with the small bowl it seems necessary. Aftermarket single-action floats seem to also run the bowl out of fuel. Due to the original double pin action, the float virtually moves straight up and down. With a single pin, the float will hit the side of the bowl before it can drop sufficiently to allow the fuel needle to drop to the smallest point in the orifice, thus causing a severe fuel restriction.
Jon.
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The YF carburetor was/is one of the very best 1-barrel carburetors ever built. First produced in 1950, it was still around when fuel injection superceded the carburetor due to smog emission concerns. There are hundreds of variations of the YF.
The first step is to determine the identification for this individual YF. Most (but not all) type YF carburetors have the number STAMPED (NOT RAISED) on the center section (bowl). The number will be three or four digits, followed by the letter "S" as in (S)am.
Once the carburetor is specifically identified, specifications may be obtained. Decent overhaul procedures are located in various Motors or Chiltons books. Check the reference section of your library.
Repair kits for all type YF up to and including the 1974 model year are readily available.
Jon.
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There are adapters available, but they change the air-flow, and don't work that well. Unless you have made MAJOR changes to the engine (camshaft, headers, compression, etc.) why not locate an original carb? That way you have the correct calibration AND everything fits.
Jon.
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The 7023054 is for a much smaller engine and SHOULD NOT be interchanged for the 7023051.
This listing from our website may be of interest:
Jon.
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The confusion with the BB Carters begins with Carter. Their literature changes FOR THE SAME CARBURETOR DEPENDING ON WHO WROTE THAT PARTICULAR PIECE OF LITERATURE! Carter referred to both updraft and downdraft carburetors as BB.
Many refer to the updraft as the BB-updraft. This includes units which Carter called BB, BB-1, and BB-2. There are 40 different versions of this updraft carburetor. The early versions had both a cast iron top (throttle body) and a cast iron lower section (bowl). Later versions came with the same cast iron throttle body, but a die-cast (zinc-alloy) bowl. To further muddy the waters, these were sold both as original equipment and aftermarket units. The units used on the Chevrolet DD trucks (C.O.E.) came in 2 throttle body sizes, and at least 3 internal venturi sizes. These units had fixed metering jets.
The downdraft units called BB are actually THREE totally different series. The first is the BBR series (used from 1933 to mid-1950's without looking). This came as a BBR-1, and BBR-2 (the 2 was a larger throttle body). These carbs were used on a number of Chrysler, Studebaker, Federal Truck, I.H.C. truck, etc.
The second BB downdraft series was the BBD two barrel used by Chrysler and DeSoto in the early 1950's. These unit had aluminum water heated throttle bodies, and did not survive well.
The third BB downdraft series were the BBS (single) and BBD (dual or 2 barrel) units produced for Chrysler from the mid-1950's through the end of carbureted engines on Chrysler.
Hopefully, this will clear some of the confusion.
And one question I would pose to the Chrysler specialists: WHY did Chrysler specify that the normal position of the throttle on these units was NOT idle. The pump return spring is so designed on most of these units such that if the throttle return spring on the vehicle were to break, the engine would immediately race to wide open throttle??? Wasn't this ever considered a safety issue???
BL - the late 1950's Chevrolet DD would have used Carter 871s on the 235; and 2075s on the 261. Chevrolet used many other numbers in earlier years.
Jon.
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A little additional information. While it was often true that the 7th digit being odd denoted a manual transmission (primarily Chevrolet and Pontiac); it often meant automatic with air for the other divisions. In this case the non A/C carburetor was a 7023050; the one with A/C 7023051.
You will find MANY anomalies to the guidelines, which are just that - guidelines. ALWAYS best to check a list by tag number for exact application.
Jon.
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The documentation involved to answer this question would be quite extensive, as there are 40 different BB-1 updraft Carter carburetors. There is no single published source with the requested information.
Jon.
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Brian - without doing the research, at first blush, it would seem the 2394s would work, with minor tuning. I would not wish to state this positively without really checking into the calibrations; but it would certainly be a place to start.
We did one 2x4 for the Studebaker for a customer who wanted a very reliable "driver" with excellent "manners". For this, we used a pair of the smaller Carter AFB series carbs part number 9400s (400 CFM) and hooked them up to run as a single unit. These had the electric chokes, but this customer lived in southern Georgia, so the quick turn-off of the choke was not a problem. We fabricated adapters to adapt these to the intake manifold, and as I recall, changed the metering rods to a "Pontiac" profile (Carter never offered the AFB for used on the Packard, so we were "guessing"). The air cleaner we used was a replacement Ford oval air cleaner from the early 1960's with the unpunched base. Customer punched the base after installed the dual quads on the car. We also fabricated some custom fuel lines with the Carter glass bowl filter, and the solid linkage.
This system was not tested on a dyno, or with an exhaust gas analyzer; but the customer WAS delighted, and still buys from us, so I guess we guessed fairly well.
Since you suggested that a link was not too much of a "no-no", I would like to reference one page on our website that will help explain the selection of an aftermarket carburetor or carburetors. One should pay particular attention to the chart of both primary and secondary CFM ratings. For street use, the primary CFM rating is normally MUCH more important that the WOT rating.
Aftermarket carburetor selection
Jon.
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PackardV8 - if you wish to use other than the original carbs (Carter WCFB or Rochester 4GC which were calibrated for the Packard engine), the following almost universally applies:
(A) the air inlet for your air cleaner is smaller than the 5 and 1/8 of modern aftermarket carburetors.
(
about 1961, the intake manifold bore spacing was changed. The center-to-center of the throttle bores from side to side (fender to fender) was increased, probably necessitating the use of an adapter to place a modern carburetor on your original Packard intake.© modern aftermarket carburetors are equiped with an electric choke, which will completely open MUCH quicker than the original. If you live north of the Mason-Dixon line, this can cause engine stalling at the first stop sign with only a slim possibility of restarting until you wait a couple of hours.
(D) All modern aftermarket carburetors of which I am aware are calibrated for a Chevrolet engine (largest demand). When choosing a non-standard carburetor, one needs to consider displacement, operating environment (street or race), and engine style ("torquer" or "screamer"). Your Packard engine is a torquer. Chevrolet engines (at least those for which the aftermarket carbs are calibrated) are screamers. While we do not work on the post 1985 Carter AFB carbs (major redesign), were you to purchase a pre-1985 Carter AFB, FOR BEST RESULTS, you would need to change the main jets, metering rods, vacuum piston springs, secondary airvalve; and re-machine the idle jets, restrictors, and idle airbleeds to recalibrate for the "torquer" fuel requirement curve. Since Carter did not sell a AFB for the Packard, there are no specifications, you are your own engineer. Please note that I said "for best results". Carburetion can be anything from the factory designed carburetor (normally best after about 1950 for non-modified engines) to hiring a 15 year old to stand on the running board (older vehicles) and pour gas into the engine out of a boot! Both will work, but one works better than the other.
Now, having pointed out the major issues; the AFB and/or especially the Rochester Q-Jet and Carter Thermoquad are superior in design to either the WCFB and 4-GC. If one wishes to fabricate an intake for the Q-Jet or TQ, and spend a lot of time (and money) with recalibration; it should be possible to gain both power and economy on the Packard engine (but at what cost?). This would be a labor of love for a retired machinest.
I wouldn't even consider the post-1985 AFB's with the redesign.
As to your comment on the signature line, some would object, and I prefer not to alienate those who allow all of us the use of these forums.
Jon.
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PackardV8 - both the Rochesters and Carters (IF CORRECT ORIGINAL UNITS) will perform at a high level of excellence! In fact, far better than ANY out-of-the-box aftermarket unit!
The Carter carburetors enjoy a better reputation (WITH THOSE WHO MODIFY ENGINES); as Carter was THE high performance carburetor company during the 1950's, and actively sought the hot rod market. Carter offered many tuning parts (different profile rods, different tension springs, a plethora of jets, etc.; as well as technical support). Rochester offered pretty much only jets and power valves; but NO technical support. Most casual rebuilders of Rochester carbs are unaware of the various power valves which were offered.
If you place the original carb (either Carter or Rochester) on an original engine; you probably couldn't tell the difference in power, driveability, fuel economy, or reliability. The Carter would get the nod if one frequently drives from low altitude to high altitude, as one could acquire high altitude metering rods, which are easily changed. Calibration of the Rochester for altitude is somewhat more tricky. Either unit, if properly restored, should give thousands of miles of trouble-free use (assuming the owner changes the filters at recommended intervals, and whereever possible, avoids ethanol fuel).
As to the repair kits: this is not a commercial forum, and I try not to abuse the unwritten (or written) ethics for posting. Please make that type of request by other means. One great feature of these forums are the poster's "profile".
Jon.
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Rear
substitute an earlier carb for the same engine (see above)
1912 Buick Carburetor
in Technical
Posted
Joe - does your reference material state which model of Schebler (D or L) that may have been used; or do you have pictures? We have information that the 1911 used the model D; and the 1913 used the model L. We do not show which was used on the 1912.
Jon.