Exact positioning of the GM 4.3 distributor rotor tip

  • 6 CYL
  • 4WD
  • 113,500 MILES
I would like to know the exact positioning of the GM 4.3 distributor rotor tip. The distributor was removed without any timing marks. This is the distributor that has the spark plug wire towers out to the side(horizontal) on the cap. Where I installed it was with the tip of the rotor just about straight on or maybe 2 degrees (before top dead center) from touching the #1 cap tip. This installation is what I am use to with the older distributors with vertical towers. I tried starting the unit and it wanted to start (it was backfiring), but seemed like the timing was off maybe by 1 tooth of the distributor. Are there any pictures of the rotor tip in relations to the # 1 cap tip installation? What is timing on the vehicle(Ex. 10 degrees before t.D.C.)?
Thursday, September 24th, 2009 AT 1:57 PM

1 Reply

  • 6,383 POSTS

If the distributor is not aligned properly, it can trigger no start or poor running engine.
When installing the distributor, align the rotor segment with the number 2 mark on the base of the distributor.
Guide the distributor into place, making sure the locating slot in the distributor base fits Over the dowel pin in the intake manifold. As the distributor is being installed, you will notice the rotor will move in a clockwise direction, 42°.
When the distributor is completely seated, the rotor should be aligned with number 1 mark on the base.

I have attached the complete procedure below.

Please let me know of any questions.
Thank you.
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Friday, December 3rd, 2021 AT 2:57 PM

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