machined notch on distributor

[pippo]

People,

My 1987 sunbird GT (2 door) has a distributor of course, and I always wondered why the factory cut (machined) a quite visible notch in both the distributor base as well as the distributor (outer end). Such that they could be lined up and perhaps take the guess work out of timing. Anyone know why they are there ?

Thanks, as always, People.

 

[melsg5]

not sure if the answer is buried in this thread

Distributor notch mystery

Hi People, First time here!! lets start with a mystery: I have a 87 sunbird, GT non turbo. The distributor has 2 deep engraved notches, one on the outer section (the one you rotate to time the car) and one on the base such that if you rotate the outer you can match up the notches up to meet...

pontiacforum.com

 

[pippo]

Thanks, Mel. I forgot about that thread I started!! I guess from those replies my OBD 1 car can not get "timed" as computer takes over where ever one places the distributor. Thats how I interpret those replies/advice. I still dont understand why factory notched those cars. Am I the only one here that owns such a car?

 

[melsg5]

To typically set timing you would disconnect the computer lead to the distributor, set the initial timing, and then replug the computer lead. A hot rod trick on 82 Corvettes is to follow that procedure but instead of setting the timing to the factory spec of 6 BTDC bump it up to 12 BTDC. That usually requires a shift to a higher octane gasoline such as 89 or 91. Dont have an answer for the notches but you may get more replies.

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[pippo]

Good info, thanks. Any idea where I would find which wire is the computer lead to distributor?

 

[92 Sunbird LE]

There are 4 to the computer from the distributor....

White
Purple/White
Tan/Black
Red/Black

Doug in P.R.

 

[pippo]

There are 4 to the computer from the distributor....

White
Purple/White
Tan/Black
Red/Black

Doug in P.R.

Oh, so is that the combined 4 wire harness connector (to the distributor)?? Wow, I never knew that the connector goes to the ECM. Good to know, Mel and Doug! Thanks.