|
Register or Log In To remove these advertisements. |
|
|
|
|||||||
 |
|
|
Thread Tools | Display Modes |
06-12-2019, 06:23 PM
|
#1 |
|
Senior Member
 
Join Date: Feb 2009
Location: Northern Nevada
Posts: 7,117
|
What am I missing about ignition timing?
I replaced the chain and oil pump on a 402. The marks on timing gears are straight up 12 O-clock, and the harmonic balancer is dead-on zero. I think that means TDC to #1 (ha!). I reinstalled a Delco-Remy HEI. I didn’t mark anything, due to new paint and that, so like starting over I guess.
I turned the slot in the oil pump rod with a screw driver to approx. the #1 cylinder. Then set the distributor forward, marked the distributor where the front LH rotor will face the #1 cylinder, and spun the rotor to the marking. From there I was able to mesh the gears very easily, goes straight in, but here is where I’m lost. After I mesh the gears, and as I lower it further into the gears - or more likely insert the distributor rod into the oil pump rod, the rotor swings clockwise to approx. straight forward. Corrections welcome, but I think its right. Edit: The rotor must land on #1. Assuming it’s right, how come the initial rotor position (near forward) doesn’t screw things up? What am I missing?
__________________
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 of OEM identifications and part numbers, all 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 08:29 PM. |
|
|
|
06-12-2019, 06:55 PM
|
#2 |
|
Registered User
Join Date: Jan 2017
Location: cortland ohio
Posts: 23
|
Re: What am I missing about ignition timing?
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.
|
|
|
|
06-12-2019, 07:19 PM
|
#3 |
|
Registered User
Join Date: May 2016
Location: Henderson NC
Posts: 975
|
Re: What am I missing about ignition timing?
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.
|
|
|
|
|
06-12-2019, 07:34 PM
|
#4 | ||
|
Senior Member
Join Date: Feb 2009
Location: Northern Nevada
Posts: 7,117
|
Re: What am I missing about ignition timing?
Quote:
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:
__________________
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 of OEM identifications and part numbers, all 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. |
||
|
|
|
|
06-12-2019, 08:24 PM
|
#5 | |
|
Registered User
Join Date: May 2016
Location: Henderson NC
Posts: 975
|
Re: What am I missing about ignition timing?
Quote:
|
|
|
|
|
|
| Bookmarks |
| Thread Tools | |
| Display Modes | |
|
|
Linear Mode
