How to rebuild automotive carburetors
From Crankshaft Coalition Wiki
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==Introduction== | ==Introduction== | ||
Sooner or later, every hotrodder runs into the steps of making induction and carburetion choices while building a performance engine. | Sooner or later, every hotrodder runs into the steps of making induction and carburetion choices while building a performance engine. | ||
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The difference between the correct and too rich/lean jet sizes may only be 0.002”-0.004”. There are no readily available drill bits that are that close in size to one another. So at best, the changes made to jets by hand drilling are going to be in steps decided by the availability of drill bits. Because drill bits are often available in 1/64” increments (the small numbered bits- which have a finer increment between bits- are too small for drilling the average carb metering jet), this will be on the order of a 0.0156” change between drill bits- which is HUGE (~40%) change in metering area when in the 0.070” jet orifice range. | The difference between the correct and too rich/lean jet sizes may only be 0.002”-0.004”. There are no readily available drill bits that are that close in size to one another. So at best, the changes made to jets by hand drilling are going to be in steps decided by the availability of drill bits. Because drill bits are often available in 1/64” increments (the small numbered bits- which have a finer increment between bits- are too small for drilling the average carb metering jet), this will be on the order of a 0.0156” change between drill bits- which is HUGE (~40%) change in metering area when in the 0.070” jet orifice range. | ||
| − | + | There is no practical way for a person to casually drill an orifice and know what the change in flow will be. Drilling orifices by hand is mostly an anachronism. Nowadays, better options are almost always readily available. Only rare and/or extreme circumstances dictates such practices. | |
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| + | Highly educated engineers work with mathematical formulas to design correct sized orifices. During the formative years of our contemporary automotive racing environments, carburetors were not always made with a full range of ready made fuel and air bleed orifice replacements so carburetor tuning 'magic' was done with a drill. Because of the difficulty in obtaining precision, for those reasons listed above, a general recommendation to purchase an assortment of pre-calculated metering orifices (fuel or air bleeds) is emphasized. Nevertheless, carburetors exist that do not have readily available interchangeable orifices, and these warnings are made to caution the ambitious tuner. | ||
===Quadrajet Tuning and Repair Parts=== | ===Quadrajet Tuning and Repair Parts=== | ||
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==Carter carb== | ==Carter carb== | ||
| − | [http://www.mymopar.com/downloads/carterafbtuning.pdf Carter AFB Selection and Tuning Guidelines] from Federal Mogul | + | ===AFB=== |
| + | *[http://www.mymopar.com/downloads/carterafbtuning.pdf Carter AFB Selection and Tuning Guidelines] from Federal Mogul | ||
| + | *[[Media:Afb rebuild guide.pdf|How to Overhaul and Tune your Carter AFB or Edelbrock EPS Four Barrel Carburetor]] | ||
| + | *[[Media:Carterafbtuning.pdf|Carter AFB Selection and Tuning Guidelines]] | ||
| + | ===Thremoquad=== | ||
[[Image:Thermoquad.jpg]] | [[Image:Thermoquad.jpg]] | ||
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[[Category:Carburetors]] | [[Category:Carburetors]] | ||
[[Category:Engine]] | [[Category:Engine]] | ||
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