By Bob Donalds
| When your original distributor fails, or if you just
want to get the latest and greatest, you reach for the fully centrifugal
009 distributor or one of its cousins. When the 009 is used with the 30-PICT-3
or any 34 PICT carburetor, problems begin to happen faster than you can
turn the adjustment screws. Where do you time the new distributor? Do
you use the old timing mark? What does the old timing mark mean?
Why won't my engine idle?
First, most original distributors in the dual port were designed to run with an idle timing of 5 degrees AtdC (After Top Dead Center). The 009 should be timed at 10 degrees BtdC (Before Top Dead Center). Setting the 009 at a timing mark of 5 AtdC would give you an inadequate advance of about 17 degrees total.
Now your engine may idle nicely but you risk melting a piston. The air cooled type 1, pre 72 type 2, and type 3 VW engine needs a total advance of 32 degrees BtdC up at the fan belt where it lifts off the pulley. When the 009 is set at 10 degrees, this timing change of 15 degrees raises the idle so high you need to lower it by turning the idle speed adjusting almost all the way. Naturally this shuts down the idle circuit. The engine is now getting so little fuel; it barely idles. If it does idle, it won't transition to the next carburetor circuit without massive hesitation even with a good accelerator pump. Also, the throttle plate if not closed at warm idle, will create the same effect.
On the dual port crank pulley there is a dent on the opposite side of the original timing mark and slightly to the right. I take the middle of this dent as 0 degrees. Take the points of an open-end 15 mm wrench and lay the left side of the wrench in the middle of the dent and the right side will fall at approximately 10 degrees BtdC. File a new notch at that spot, I then mark it with red touchup paint. The next step to a proper idle is to install a pop rivet in the hole of the throttle plate. Trust me, it works. This is the brass plate at the base of the carburetor that opens when you press the gas pedal. Now all the air the engine draws in at a idle must come through the idle circuit. You can now back out the idle speed adjusting screw, restoring the idle by allowing enough air into the carburetor idle circuits thereby picking up the fuel needed to obtain an idle. You can now set the timing at 10 BtdC with your 009 distributor and have the fuel needed for a stable idle and smooth transition to the high-speed circuits.
When rebuilding engines, I lower my compression ratio to prevent pre-ignition and overheating with a semi-hemi cut in the combustion chamber. This allows me to run 2 to 4 degrees more timing without the engine getting too hot. The carburetor might also need a larger main jet. Does the engine run out of power just past the idle at 1500 rpm or so and putting the pedal to floor isn't much help? I find larger, main jets commonly needed to help with this midrange hesitation and additionally can increase top end. My best guess for main jet size on a otherwise stock engine is # 135 the carb comes stock with a # 127.5 unless it's a 71 type 2 then it's a #125. Gene Berg Enterprises is a good source for main jets. Changing the main jet to a larger size can improve gas mileage because less gas pedal is needed to get up to speed. Rejetting is common when running a non-stock exhaust. These exhaust lower the back pressure and tend to lean the motor out. Of course before rejetting, be sure you have reviewed the basic tune-up, having a proper pre-heater for the carburetor below 50 degrees. Check your valve adjustment and make sure you have enough compression for the motor to idle. Any cylinder with under 100 pounds compression will not fire at an idle. Tuning for performance is done one change at a time with a fully warmed up engine, and the test drive is the measure of success. The original timing set up with the idle settings at 5 degrees BtdC was to reduce hydrocarbons for the now standard tail pipe emission test. Be clear that the 009 distributor will increase tail pipe hydrocarbons when timed . Depending on the emission laws where you live, this can make the difference when trying to pass the tail pipe sniff test.