How to rebuild automotive carburetors
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[edit] Introduction
Sooner or later, every hotrodder runs into the steps of making induction and carburetion choices while building a performance engine.
For some, it's a tough choice whether to buy a brand-new carburetor, or to find an old dirty one and rebuild it. While buying a new carburetor may be convenient, at $200 and up, the cost can be prohibitive for the budget-minded hotrodder.
On the other hand, a brand-name carburetor rebuild kit may cost as little as $15, and the rebuilt carb, (if rebuilt correctly), will last many years to come.
[edit] Where to start
Things to consider when choosing your first rebuild victim...
- CFM, and how much do I need? (Cubic feet per minute of air/fuel mixture)
Link to a handy CFM Calculator, http://www.4secondsflat.com/Carb_CFM_Calculator.html
- Spreadbore vs. squarebore -- which one is required?
- Parts and rebuild kit availability
[edit] Holley Carb specifics
The Standard Holley 4 barrel carburetor. Along with some other carbs,Its design has changed very little over the years, and the design and tuning method still works on most of the newer ones. Easy to rebuild, easy to tune, and having LOTS of aftermarket hop-up parts, the 4bbl Holley may be the best choice for you!
[edit] Rochester Carb specifics
The Q-JET,quadrajunk,quadrapuke,whatever you won't to call it,if properly tuned,is probably one of the best carburetors available on the market.It does have it's restrictions though.If you are running a fairly healthy cam profile,that has a tendency to limit your vacuum level,the q-jet has a difficult time in the power piston area.Several companies do make different springs for this,but I can tell you from experience,if the cam is to big,it will give you problems.With it's centrally located fuel bowl and the affore mentioned power piston,the quadrajet is a great all-round carb for street machines and if your doing a restoration on a 60's or 70's muscle car,the carb just can't be beat.Once tuned,it stays that way,with very little need for upgrades or maintenance.It's true,that it is a little more difficult to rebuild because of it's varied tuning characteristics,but that is the beauty of the beast,you can make it work on just about any engine design.With it's small primaries,you can cruise and get reasonable fuel mileage,or you can kick in those monster secondaries,forget about fuel mileage,and fly.Most rebuild kits come complete with instructions and application charts for whatever engine your working with,and you can always do what I do,hold on to the parts you didn't use before,and use them on your next rebuild or experiment.Several companies,namely Edelbrock,have started making everything you need to change whatever you want to change,to make the carb fit your needs,or you can buy one of their new ones,and I do mean new,not reman,and not worry about spending all of your time in the shop.JetPerformance also makes a great Q-jet.Their unit is a true bolt on and go product.I have used 3 of their carbs,which by the way come in stages to meet your application,and I never had to tune one of them.I bolted to the intake,and took for a test drive,and never had to tune from that moment forward.Again,if your running a nice little street engine with a little thump,you can't find a better carb,but if your getting into that monster pro=street stuff,than you need to look at carburetors that can handle the changes in vacuum circuits and the need for fuel.
[edit] Carter Carb specifics
[edit] Stromberg Carb specifics
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