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Old 06-12-2019, 07:34 PM   #4
71CHEVYSHORTBED402
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Join Date: Feb 2009
Location: Northern Nevada
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Re: What am I missing about ignition timing?

Quote:
Originally Posted by garyd1961 View Post
Set your distributor in the hole but don't engage the gears. Turn the rotor to the correct spot. Carefully lift the distributor back out not moving the rotor. Lay the distributor straight back and look at the position of the slot. Turn the oil pump shaft to match the distributor. Back the rotor back enough so so that it rotates to the correct spot when all the way down. Usually takes me a couple tries to get It right.
I think I see what you mean, and I did most of that. I believe you're saying turn the rotor to counter-clockwise a spot, so when it engages it lands toward the #1 cylinder. I'll give it a go.

Gave it a shot, I think it's right now (image). I started it with the rotor facing #1, spun the rotor counter clockwise some, dropped the rest and she appears correct now. On a side, I'm hiring out the first start on this, so they have to pull the distributor and prime anyway. But I like to know how things work.

OT: Both my 402 have HEI. The bolt that secures the brake booster bracket to the intake was removed from both trucks, because the bolt head doesn't clear one of the distributor cap hooks. 5/16-18 button heads are the ticket, you can buy them in black oxide.

Quote:
Originally Posted by truck-kid View Post
Sounds like you are engaged 1 tooth off as Rotor must point to #1 when fully engaged.Remove distributor and turn oil pump driveshaft counter clockwise slightly untill you can drop distributor in and it points towards #1 on the cap. You can verify correct position when your done by with #1 plug out turn engine over by having someone bump starter or turn over by hand untill #1 just starts to build compression then continue turning by hand till tdc marks align on balancer and timing tab.The rotor should point to #1 on the cap.
Thanks for the info.
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Tony
71 Custom Deluxe, SWB, 2WD, 402, A/C. I developed an assm. guide "kit" for restoring it from ground up. With assys, the guide accts for 1000s details such as OEM identifications& part numbers, written in short order. 700+ images include assm, illust., charts, and points of interest. Much of the info. applies to all 67-72 GM trucks, and to a lessor degree all 67-72 GM vehicles. My build thread, and more on the guide https://67-72chevytrucks.com/vboard/...d.php?t=730025

Last edited by 71CHEVYSHORTBED402; 06-12-2019 at 08:28 PM.
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