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Chevy man
Chevy man, Chevy Technician
Category: Chevy
Satisfied Customers: 4942
Experience:  ASE Certified as an L1 Master Technician with extensive experience in Chevy products
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Trying to set ignition timing for a chevy 4.

Customer Question

trying to set ignition timing for a chevy 4.3 v6 when bringing number 4 piston to tdc would the distributor rotor point at number 1or number 4
Submitted: 7 years ago.
Category: Chevy
Expert:  Chevy man replied 7 years ago.
What year is your truck?
Customer: replied 7 years ago.
Reply to Chevy man's Post: 1989 chevy astro van 4.3 v6
Expert:  Chevy man replied 7 years ago.

REMOVAL & INSTALLATION

See Figures 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 and 13

Click image to see an enlarged view
Fig. 1: Connector identification for distributor-2.5L engine


Click image to see an enlarged view
Fig. 2: The HVS distributor mounts only one way. Do not try to rotate the distributor to change the timing


Click image to see an enlarged view
Fig. 3: Align the indent hole on the drive gear with the cast-in arrow before installation on the HVS distributor


Click image to see an enlarged view
Fig. 4: With the indent hole and cast-in arrow aligned, the rotor should point in this direction


Click image to see an enlarged view
Fig. 5: Connector locations on the HVS distributor


Click image to see an enlarged view
Fig. 6: With the HVS distributor properly aligned and installed, the rotor should point to the mark


Click image to see an enlarged view
Fig. 7: Tag all the ignition wires before removing them from the cap or the spark plugs


Click image to see an enlarged view
Fig. 8: Disconnect the harnesses from the module


Click image to see an enlarged view
Fig. 9: Mark the alignment of the rotor before removing the distributor


Click image to see an enlarged view
Fig. 10: Mark the distributor base-to-block alignment before removing the distributor


Click image to see an enlarged view
Fig. 11: The distributor hold-down bolt must be removed to be able to draw out the distributor


Click image to see an enlarged view
Fig. 12: Depending on the hold-down's shape, there may be a correct orientation, so note how it is mounted


Click image to see an enlarged view
Fig. 13: Draw the distributor body straight up and out



Engine Not Rotated

This procedure applies if the engine has not been rotated with the distributor removed.

  1. Disconnect the negative battery terminal from the battery and remove the console cover.

  2. Tag and disconnect the electrical connector(s) from the distributor.

  3. Remove the distributor cap (DO NOT remove the spark plug wires) from the distributor and move it aside.

  4. Using a crayon or chalk, make locating marks (for installation purposes) on the rotor, the ignition module, the distributor housing and the engine block.

  5. Loosen and remove the distributor clamp bolt and clamp, then lift the distributor from the engine.

Noting the relative position of the rotor and the module alignment marks, make a second mark on the rotor to align it with the one mark on the module.

To install:

  1. Install a new O-ring on the distributor housing.

  2. Align the second mark on the rotor with the mark on the module, then install the distributor, taking care to align the mark on the housing with the one on the engine.

It may be necessary to lift the distributor and turn the rotor slightly to align the gears and the oil pump driveshaft. The crankshaft may have to moved very slightly to engage the oil pump driveshaft with the distributor. Do NOT force the distributor into the engine with the distributor clamp.

  1. With the respective marks aligned, install the clamp and bolt finger tight.

  2. Install and secure the distributor cap.

  3. Connect the electrical connector(s) to the distributor.

  4. Connect a timing light to the engine (following the manufacturer's instructions). Start the engine, then check and/or adjust the timing.

  5. Turn the engine OFF, tighten the distributor clamp bolt and remove the timing light.

Engine Rotated

This procedure applies when the engine has been rotated with the distributor removed.

  1. Disconnect the negative battery terminal from the battery and remove the console cover.

  2. Tag and disconnect the electrical connector(s) from the distributor.

  3. Remove the distributor cap (DO NOT remove the ignition wires) from the distributor and move it aside.

  4. Using a crayon or chalk, make locating marks (for installation purposes) on the rotor, the ignition module, the distributor housing and the engine.

  5. Loosen and remove the distributor clamp bolt and clamp, then lift the distributor from the engine.

Noting the relative position of the rotor and the module alignment marks, make a second mark on the rotor to align it with the one mark on the module.

To install:

  1. Install a new O-ring on the distributor housing.

  2. Rotate the crankshaft to position the No. 1 cylinder on the TDC of compression stroke. This may be determined by inserting a rag into the No. 1 spark plug hole and slowly turning the engine crankshaft. When the timing mark on the crankshaft pulley aligns with the 0 mark on the timing scale and the rag is blown out by the compression, the No. 1 piston is at top-dead-center (TDC).

  3. Turn the rotor so that it will point to the No. 1 terminal of the distributor cap.

  4. Install the distributor into the engine block. It may be necessary to turn the rotor, a little in either direction, in order to engage the gears.

  5. Tap the starter a few times to ensure that the oil pump shaft is mated to the distributor shaft.

  6. Bring the engine to No. 1 TDC again and check to see that the rotor is indeed pointing toward the No. 1 terminal of the cap.

  7. With the respective marks aligned, install the clamp and bolt finger tight.

  8. Install and secure the distributor cap.

  9. Connect the electrical connector(s) to the distributor.

  10. Connect a timing light to the engine (following the manufacturer's instructions). Start the engine, then check and/or adjust the timing.

  11. Turn the engine OFF, tighten the distributor clamp bolt and remove the timing light.

 

Customer: replied 7 years ago.
Reply to Chevy man's Post: the answer is not helping me sr all it is on a totally differant subject
Expert:  Chevy man replied 7 years ago.

Those were the instruction to remove and install a distributor. Your question was how to align the distributor rotor.

Once your distributor is in the right position, then you can use a timing light t set the timing as follows

 

NOTE: Timing specifications are listed on the Vehicle Emissions Control Information label under the hood. Always follow the Vehicle Emissions Control Information label procedures first before using the following procedure.

PROCEDURE:

Set timing under the following conditions:



Normal operating temperature.
Air cleaner installed.
A/C "OFF".
Transmission in neutral.
Disconnect SET TIMING connector (tan/black wire) located in harness close to distributor. DO NOT disconnect 4 wire connector at distributor.
Connect timing light and adjust as necessary by loosening hold down bolt and rotating distributor. For specification, refer to SPECIFICATIONS/ELECTRICAL AND ELECTRONIC SPECIFICATIONS/TIMING SPECIFICATIONS. Tighten hold down and recheck the timing. Stop the engine and connect SET TIMING connector. Clear ECM trouble code by disconnecting ECM power source.

NOTE: Dual timing scribes are on the 4.3L engine balancers. They line up with the timing indicators at one o'clock and four o'clock positions. Use the one o'clock position.






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