Technical Tips

123 Tune Distributor | Measure Cylinder Head | Fix Spica Run-On | Injection Pump Timing

Spark Plug Reading

Send me a picture of your spark plugs, This a normal looking set of
plugs where all four plugs look about the same with brownish deposits on the porcelain cones.

The height, angle and lighting allows reading of the plugs.

123 Tune Distributor

The 123 Tune Plus distributor is a very popular engine upgrade.

Here is the recommended timing advance: RPM/Degrees.
1000=13 2000=28 3000= 33to 34 4000=36/37 8000=36/37. Rev limit 6000/6500.

Individual throttles (Weber Carbs and Spica Injection) do not use vacuum advance. There’s a lot of confusion; the 123 instructions do not mention this and we do not recommend installing a vacuum hose between the port on the distributor and the port on the idle tower of the Spica engines. We are currently testing this feature on our personal Alfas. Send me a message with your phone number if you want to use this feature. I will call you back.

How To Measure the Cylinder Head Thickness

Tools needed: 6 inch Caliper, metal straight edge.

Measuring head thickness: place straight edge under stud
hole and insert the stem of the caliper through the hole until it
reaches the straight edge. 
This picture (example) shows the head head thickness : 4.40 inches. The factory standard head thickness for the 1600, 1750 and 2L heads is 4.410. This head has been milled .010 inches.

Take several measurements and email the results. We  need this information before ordering pistons.

Permanent Cure for SPICA Starter Run-On

On Spica Alfas, the factory 12 AWG BLACK wire runs from the ignition switch to the starter solenoid spade terminal. A jumper wire branches from this spade to the Spica Cold Start Solenoid (CSS).

As solenoids age, internal electrical shorts can form. Releasing the key back-feeds voltage from the lower starter field post into the ignition /CSS circuit. This electrical loop mechanically latches the solenoid, forcing the starter motor to “run-on” requiring pulling the wire off the CSS to stop the “run-on”.

THE SOLUTION: The lower Post Bypass.

Bypassing the starter solenoid spade terminal completely breaks this feedback loop. By routing the 12 AWG CSS wire directly to the lower starter post, the ignition switch and CSS are isolated from the starter solenoid.

MATERIALS NEEDED

  • 1x 5/16” (M8) Ring Terminal (12-10 AVG size, heavy duty tinned copper)
  • Marine-grade heat shrink tubing or high quality electrical tape
  • Wire strippers and a heavy-duty crimping tool

STEP- BY- STEP PROCEDURE

  1. DISCONNECT THE NEGATIVE BATTERY TERMINAL.
  2. PULL THICK 12 AVG FACTORY BLACK WIRE OFF STARTER SOLENOID SPADE TERMINAL.
  3. CUT THE CSS WIRE FROM THE FACTORY TERMINAL JUNCTION. INSULATE THE “WOUNDED” WIRE BARE SPOT LEFT AT THE JUNCTION USING HEAT SHRINK OR ELECTRICAL TAPE.
  4. STRIP THE INSULATION BACK 1/4 “ AT THE CUT-END OF THE CSS WIRE. CRIMP ON THE 5/16’ RING TERMINAL AND SEAL WITH HEAT SHRINK. PULL HARD ON THE NEW RING TERMINAL TOO ENSURE IT IS FIRMLY STAKED.
  5. REMOVE THE NUT FROM THE LOWER STARTER POST (THE POST FEEDING THE INTERNAL FIELD WINDINGS). ATTACH THE RING TERMINAL AND TORQUE THE NUT SECURELY.
  6. YOU CAN REMOVE ANY FACTORY DIODES OR RELAYS ON THE 77-79 SPIDERS.
  7. RECONNECT THE BATTERY. YOUR SPICA CSS RECEIVES AN IMPROVED SIGNAL DIRECTLY FROM THE LOWER STARTER POST AND RUN-ON IS ELIMINATED.

Simplified Injection Pump Timing

All of our rebuilt pumps since 2012 include our “Red Dot Pulley”.

This new pulley allows setting the injection pump timing the same as setting the ignition at the Top Dead Center (TDC) mark for cylinder # 1 compression stroke, valves closed.

  1. Rotate the engine to TDC, cylinder # 1, valves closed, distributor rotor pointing to the # 1 plug wire terminal.
  2. Rotate the injection pump pulley with the “Red Dot” aligned with the timing mark on the injection pump face.
  3. Install the pump belt. (WD 40 helps).

How to convert an original pump pulley with a new Red Dot timing mark:

  1. Locate the original pump pulley mark on the rim of the pulley.
  2. Count 14 teeth to the right, (clockwise)
  3. Drill a shallow hole in the rim of the pulley with a 3/16 drill.
  4. Fill the hole with a dab of red paint.

The original factory timing method is very confusing for many mechanics and owners. It is no longer necessary to find the “I” mark on the engine pulley or to set the pump timing different than the ignition timing or cam timing.

If for some reason you want to verify that the original pump timing mark is set correctly:
After following the new pump timing procedure (above), rotate the engine clockwise to the “I” mark. The old pump timing mark on the pump pulley will now be in alignment with the timing mark on the pump body. If you remove the # 1 spark plug you will find the exhaust valve to be open and visible through the plug hole.

Click here to download a PDF of these instructions

Engine Restoration Specialists