Idle timing

boloboss · Oct 13, 2024

I have a '84 Chevy C10 with a 350 engine. What should idle timing be set at

boloboss · Oct 13, 2024

Also, I swapped OEM distributor to a HEI distributor deleting the pigtail for (ESC)
With that being said, what should the idle timing be set on my 350 engine?

ali_c20 · Oct 13, 2024

12° advance is a good starting point. You want to set your total timing which is around 34-36° without vacuum advance.
Search youtube or google, there are many vids for setting the timing.

https://www.motortrend.com/how-to/how-to-set-initial-timing/

Ricko1966 · Oct 13, 2024

Like @ali_c20 said you are worried about total,not Idle, total will vary depending on heads,and other variables. Set your timing intentionally too low. Disconnect and plug the vacuum advance. Find 2 land marks approximately 100 yards apart.From a dead stop, accelerate from one,past the other,note your speed .Keep bumping the timing 2 degrees at a time until your trap speed levels off and starts to drop. Go back to lowest setting with highest trap speed. Reconnect your vacuum advance.

JD Miller · Oct 13, 2024

Idle timing, with vacuum advance line to distributor disconnected and plugged, should be 6 degrees . not 12

That is factory spec.

75gmck25 · Oct 13, 2024

6 is factory spec, but that was a smog era setting that was very conservative. Most stock engines work better at about 12, or even up to 16 if you have aluminum heads. Still runs fine on 87 octane.

Ricko1966 · Oct 13, 2024

And stock Idle speed timing will change as the engine wears and the timing chain stretches. And dependant on the cam,heads,intake,carbureation and distributor specs,all HEIs are not the same Don't worry about idle,give the engine what it wants.

fast 99 · Oct 13, 2024

Vacuum advance units can vary from about 10 - 30 degrees. Centrifugal weights, and springs can be much different as well. Usually, heavier [higher GVW] the truck lower total advance is.

Although total advance may have been conservative back in the emissions days have to remember octane today is much lower and fuel is not designed for carbureted vehicles. Factory specs are a starting point.

Idle timing

boloboss

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boloboss

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ali_c20

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Ricko1966

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JD Miller

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75gmck25

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fast 99

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