Installing and correctly setting a vortec distributor

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

BeXtreme

I'm Awesome
Joined
Jan 13, 2020
Messages
363
Reaction score
359
Location
Salem, OR
Same for me on an iphone. It downloads as a file, which you can then open... but also no pictures in that file.
 

Piratehunter

I'm Awesome
Joined
Nov 3, 2019
Messages
302
Reaction score
562
Location
Colorado
This link
xc_hide_links_from_guests_guests_error_hide_media
is a clip I made prior to pulling my distributor to help me with alignment of my new one after rebuilding my 454 vortec. I brought the engine to TDC for #1 and made note of where the rotor was pointing and a reference point for a distributor cap screw.

I checked the fitment and alignment of my new distributor while the engine was still on the engine stand. Noted the slot position of the oil pump shaft and how much the starting engagement of distributor gear had to be offset to mate up when installed. It dropped right in and was only off -6* when I had it checked with a scanner.

hope this helps.
 

BeXtreme

I'm Awesome
Joined
Jan 13, 2020
Messages
363
Reaction score
359
Location
Salem, OR
This link
xc_hide_links_from_guests_guests_error_hide_media
is a clip I made prior to pulling my distributor to help me with alignment of my new one after rebuilding my 454 vortec. I brought the engine to TDC for #1 and made note of where the rotor was pointing and a reference point for a distributor cap screw.

I checked the fitment and alignment of my new distributor while the engine was still on the engine stand. Noted the slot position of the oil pump shaft and how much the starting engagement of distributor gear had to be offset to mate up when installed. It dropped right in and was only off -6* when I had it checked with a scanner.

hope this helps.
Thanks, that's helpful. I found a few videos on youtube, but they all reference a mark on the inside of the cap(which doesn't exist on my distributor for some reason) or a mark on the shaft(which also doesn't exist on mine). I was able to do a general visual ID from one of the videos and it appears to mostly line up with what you are showing in your video. I don't have a rotor on mine because I went 24x and CNP. Hopefully I can get it the rest of the way together and the wiring harness reworked this week so I can start getting it swapped into the old squarebody. I'll have to wait for all of that before I can crank it over to check the CMP offset.
 

RCFallis

Newbie
Joined
Jun 23, 2023
Messages
11
Reaction score
3
Location
Muskogee
you can NOT run timing advance at the distributor on a computer controlled L31 engine, like you could in older engines. the timing advance is completely computer controlled. you need to set the distributor at 0* +- 2* for proper operation, you can change the timing in the PCM with a tune if you have the hardware/software to do so...

also I highly doubt that any phone app will be able to read the CMP offset, its a very specialized GM only sensor that was only used for a few years, there are only a few scanners/loggers that I know of that can read it, the usual run of the mill live data code reader usually doesn't support it. if you have the app and it does allow logging of the CMP offset, let us know, that would be very helpful.
Harbor Freight has a Bluetooth for android that reads CAM. $65 with lifetime updates. It reads way more than CAM.
 

Attachments

  • IMG_6786.jpeg
    IMG_6786.jpeg
    194.7 KB · Views: 8
  • IMG_6762.png
    IMG_6762.png
    855.4 KB · Views: 9
  • IMG_6765.png
    IMG_6765.png
    490.2 KB · Views: 6
  • IMG_6764.png
    IMG_6764.png
    654.2 KB · Views: 9

A97obs

I'm Awesome
Joined
Jun 29, 2022
Messages
261
Reaction score
177
Location
USA
Yup doing my vortec distributor was a nightmare only because I never made the “Important and necessary “ marks prior to yanking it out.
It’s definitely super tedious to drop in without the marks and hope the rotor aligns with cyl#1 . A lot times you got to take a flat head and drop it down in and adjust the oil pump drive shaft in order to align the with distributor notch based on the way your distributor drops in.
 

BeXtreme

I'm Awesome
Joined
Jan 13, 2020
Messages
363
Reaction score
359
Location
Salem, OR
Yup doing my vortec distributor was a nightmare only because I never made the “Important and necessary “ marks prior to yanking it out.
It’s definitely super tedious to drop in without the marks and hope the rotor aligns with cyl#1 . A lot times you got to take a flat head and drop it down in and adjust the oil pump drive shaft in order to align the with distributor notch based on the way your distributor drops in.
Technically you never need to align an oil pump drive shaft. You can drop the distributor in at the correct spot, then snug the hold down clamp on just enough to keep the distributor from jumping up and out of the gear. Then just bump the engine over until it drops down onto the oil pump drive. You won't slip or change the distributor/cam interface by doing that, it just spins them both together until it lines up with the oil pump drive... usually 1/4-1/2 a turn of the engine is enough.
 

A97obs

I'm Awesome
Joined
Jun 29, 2022
Messages
261
Reaction score
177
Location
USA
Technically you never need to align an oil pump drive shaft. You can drop the distributor in at the correct spot, then snug the hold down clamp on just enough to keep the distributor from jumping up and out of the gear. Then just bump the engine over until it drops down onto the oil pump drive. You won't slip or change the distributor/cam interface by doing that, it just spins them both together until it lines up with the oil pump drive... usually 1/4-1/2 a turn of the engine is enough.
Actually maybe not technically There are many written instances where people explain the need if the process isn’t going correctly. And especially if you pull it out with the marks not marked If your trying to drop it in and end up with rotor pointing at #1 cyl and the oil
Shaft notch is jarred a hair to the 11 or 1pm position the notch on the dist won’t align and it won’t seat on the manifold and so on and so forth. I heard about bumping the engine, but I found it as easy to do long flat ahead, and just correct the position on oil pump, shaft manually.
We’re talking about rare cases or someone who’s trying to figure it out after thy fd up and pulled a distributor without being on tdc and without making any alignment marks on the dist cap or rotor etc … every time I drop mine in the rotor twisted it was about an inch past the number one cylinder.
I’d have to be back in the moment again to know what I did , but I knew what I was doing wrong at the time and I just took a little bit of time to correct being a tooth off timing
 
Last edited:

A97obs

I'm Awesome
Joined
Jun 29, 2022
Messages
261
Reaction score
177
Location
USA
Technically you never need to align an oil pump drive shaft. You can drop the distributor in at the correct spot, then snug the hold down clamp on just enough to keep the distributor from jumping up and out of the gear. Then just bump the engine over until it drops down onto the oil pump drive. You won't slip or change the distributor/cam interface by doing that, it just spins them both together until it lines up with the oil pump drive... usually 1/4-1/2 a turn of the engine is enough.
that’s useful info I’ll remember thar part about bumping the engine a hair with pressure on the hold down clamp . But I really learned my lesson on that repair . I marked everything ahead for next time if there is one after I got it done
 
Top