6066 (1960-1966) GMC Truck Club

6066 (1960-1966) GMC Truck Club (https://6066gmcclub.com/index.php)
-   I-6 Engines (https://6066gmcclub.com/forumdisplay.php?f=17)
-   -   Going to HEI distributor and screwing up (a lot?) (https://6066gmcclub.com/showthread.php?t=50079)

Dano64 July 6th, 2017 02:54 AM

Going to HEI distributor and screwing up (a lot?)
Hi guys.

Got my 64 maybe a month ago and it was running roughly. Not so so bad but high idle needed to not stall. Determined that the timing and/or ignition might be screwy so set out to improve it as this is really the only major issue between the truck being driveway decoration and usable.

Setting aside the idea that I may have been wrong about the entire source of problems - like whether the distributor/timing was an issue at all (sigh) I am committed to the new distributor now. Likely mistake #1. Not really worried if this wasn't the original problem as I'm sure this ultimately will make it a better runner.

OK; here are the main points.

Thought I had an old mechanical distributor with no vacuum advance because that's all I saw from the top and I didn't look closely (mistake #2 if we're keeping count). Turns out it was a Pertronix Ignitor II electronic unit, likely installed in 2011 when motor was rebuilt. No vacuum. Maybe fine. Maybe toast.

Read some posts here from TJ and did some online research; had a hard time finding top dead center and tried replacing the distributor by simply matching the rotor position. Goof #3?

I felt like that was a success then realized I had wired my distributor for CCW instead of CW. #4. (sigh; rewired) and it seemed like maybe the two distributors were not "clocked" the same way so I lost faith in the correctness of the rotor position also.

(stopping the mistake count, too embarrassing)

Realized that where I had the number one wire was a few positions different than where EVERY OTHER distributor seemed to be compared to photos online. Combining this with the loss of faith in the correctness of the rotor position and I moved the wires again, carefully checking the correct firing sequence (and doing it CW!). No Fire.

Unable to feel confident about a TDC check, and compulsively 'doing something' yesterday I trusted the marks on the harmonic and set the timing (manually, not running) to about 4 BTDC by lining up the rotor to #1 plug wire. No fire. Also tried various timing positions after that, spitting gas vapors out of carb and feeling like a genius while my son holds the hose and has safety glasses on nearby. (Not *that* near.)


So it ran better when I got it than it does now. Suggestions on what I imagine is like doing a distributor job on an engine that is not 'known good'? Sigh.

TJ's GMC July 6th, 2017 04:20 PM

Re: Going to HEI distributor and screwing up (a lot?)
As long as the firing order is correct you can place number 1 on the dizzy wherever you want. Can you show some pictures of your setup?
If you'd like I could make a video walking you through setting the timing and checking for spark.

Dano64 July 17th, 2017 12:38 AM

Re: Going to HEI distributor and screwing up (a lot?)
Hi. I made a video of what I'm looking to do. Would you tell me if this makes sense?? Thank you.

Updated the link, I posted one that wasn't shared at first.


Dano64 July 17th, 2017 03:16 AM

Re: Going to HEI distributor and screwing up (a lot?)
Holy crap it worked. The lifter checking method got me to a reliable TDC; from there I found my rotor was inexcusable off and it would have never worked. First try it fired up after that.

Following that... lots of futzing with timing then realized that timing with the vacuum on was all wrong...

Got to a non-vacuum timing of about 4 degrees and smooth (mostly) idle of about 1500 w/o choke.

I think I need to move it to 6-8 but I'm taking a glory-I-got-it-running drive first.

TJ's GMC July 18th, 2017 04:33 AM

Re: Going to HEI distributor and screwing up (a lot?)
Don't be afraid to advance the timing to 10 degrees, I've experienced and so have many others that there can be lost power with so little initial. Try it at 8 and if it has good power then leave it, but if you notice it's sluggish or pulls hills poorly try advancing a little more. Glad it's running! Drive the wheels off it! :thumbsup:

Dano64 July 22nd, 2017 10:08 PM

Re: Going to HEI distributor and screwing up (a lot?)
Ok, thanks! This is just what I'll do. Then... I think... I will try adjusting carb mixture with vacuum gauge. That's just warming up motor and tinkering for max vac, yeah?

TJ's GMC August 4th, 2017 07:39 AM

Re: Going to HEI distributor and screwing up (a lot?)
Max I was able to pull was 16-18 with my 305. Initial at 8 degrees. 4-6 is the spec.

All times are GMT +1. The time now is 01:48 AM.

Powered by vBulletin® Version 3.8.6
Copyright ©2000 - 2022, Jelsoft Enterprises Ltd.