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#1 |
Senior Member
![]() Join Date: Jan 2025
Location: Clarkdale, Arizona in a van down by the river
Posts: 247
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Timing settings help
I set my timing yesterday at 16 degrees btdc for 3500 ft elevation where I live and unplugged the vacuum advance and plugged the port.
It runs great and I am getting a reading of 35 degrees at 3000 rpm with the vacuum advance unplugged. With the vacuum on the dist. plugged in at 3000 rpm I am getting a reading of 55 degrees advance. Is this an issue, am I misreading something or doing it wrong. This is with a harbor freight timing light with the advance dial on it. The truck runs good now like a streak of **** and will turn over the rear tires. It also stays cool on highway or in town or just idling. Last edited by IT Cowboy; Today at 04:19 PM. |
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#2 |
Senior Member
![]() Join Date: Sep 2014
Location: Wenatchee, Wa
Posts: 969
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Re: Timing settings help
Your vacuum advance is adding 20 deg of timing in a no load situation..
With 15 initial connect the vac advance and you should see 35 deg on the timing light. Sounds like it is working correctly. |
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#3 |
Registered User
Join Date: Aug 2012
Location: Oklahoma City, OK
Posts: 2,655
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Re: Timing settings help
2nd the thought it is working properly. 50~55 is the normal expected total light throttle advance.
The higher initial timing normally does cool the idle temps a bit as it is using less fuel to keep running. Don't worry about exact numbers. There is some variation between balancer timing marks, the mass produced timing cover, the mass produced timing indicator that is spot welded to the timing cover. Yours may be +/- a few degrees compared to the next one. |
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#4 |
Registered User
Join Date: Jun 2019
Location: Chehalis, WA
Posts: 133
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Re: Timing settings help
Those numbers are all within workable ranges. The initial is somewhat high, but you're at altitude.
As long as you're not getting any detonation under acceleration, you're good. |
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#5 |
Senior Member
![]() Join Date: Jan 2025
Location: Clarkdale, Arizona in a van down by the river
Posts: 247
|
Re: Timing settings help
Ok, thank you all and I thought I was ok since it seems happy and runs well. The difference at 3000 rpm when plugged into the vacuum (55) vs when not plugged into it (35) is what made me question it as ChatGPT acted like the 55 advance number was way too high.
It does seem just a little harder to start when it is warm but I guess that is normal and it still snaps right off but maybe just a second or so more to crank.
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'72 C10 / 402 ___________________________________________ Freedom isn't safe, it requires you to take responsibility for your own life, your own safety, and your own success. It carries with it the possibility of failure and the understanding that you're working without out a safety net. If you give the state the responsibility for any of these you also give up the freedom that accompanies the responsibility. |
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