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What base timing have you started with?

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Old Mar 3, 2015 | 07:24 PM
  #1  
Mark_ZZ3's Avatar
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From: Alberta, Canada
Car: 1989 Camaro-1LE
Engine: TPI(s)
Transmission: 5 speed (MM5, MK6)
Axle/Gears: 3.45, 3.73
What base timing have you started with?

Curious what base timing people find as a good starting point. The book says 6 degrees.

Is it better to leave the base at 6 and change the settings in the spark table or set base at 10 adjust the spark tables above that?

Thanks for any experience you can share. When the snow clears, I can do some testing. For now, it's still bench racing.

Mark.
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Old Mar 4, 2015 | 07:07 AM
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From: Chasing Electrons
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Re: What base timing have you started with?

The base timing is only used during cranking and limp mode (ECM or code 42). As such set it so that the engine cranks and catches when cold, with a hot-restart not kicking back on the starter.

Note that the physical base timing and the initial SA value in the calibration have to match.

The other item that the base timing affects is the range of 'at crankshaft' spark advance. This has to do with the rotor to cap constraints of a distributor (DIS isn't as constrained).

RBob.
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Old Mar 4, 2015 | 06:15 PM
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Re: What base timing have you started with?

I run 10°.

The reason I run 10° is because my large cap distributor hits the Miniram fuel rail and stops... where it stops is 10°. Makes it very convenient when R&R-ing the distributor... no need for a timing light.
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Old Mar 4, 2015 | 11:46 PM
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Re: What base timing have you started with?

Originally Posted by RBob
with a hot-restart not kicking back on the starter.
RBob.
This would be a result of having the timing advanced to much correct?
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Old Mar 5, 2015 | 07:25 AM
  #5  
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From: Chasing Electrons
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Re: What base timing have you started with?

Originally Posted by IROCThe5.7L
This would be a result of having the timing advanced to much correct?
Yes, too much initial advance on a hot engine will kick back on the starter.

With a cold engine not having enough advance will cause the engine to windmill.

RBob.
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