Setting Simple Ignition Points
 

I have two 1960's GMC vehicles with V6 engines. A 305E in a pickup and a 351C in a medium duty truck. Both of these have the distributor stuffed in the back of the engine and use what I call "loosen and try again" style ignition points (no distributor window or points adjustment screw). I am having a devil of a time setting them, especially in the truck, with my "try again" often leading to worse results when checked with a dwell meter. My routine is to use a feeler gauge to try to get a point gap close to the specified spacing, then check with a dwell meter to see if the setting is acceptable. But re-adjusting is more like starting over than fine-tuning. IS THERE A METHOD FOR DOING THIS THAT I AM MISSING. There are slots in both the distributor plate and the points that appear to allow using a screwdriver to spread or close the point gap, but I haven't figured out how to make this work. And the clearances at the back of the engines don't give much room for maneuvering with more than a couple of fingers.

I have learned by experience that point settings and function make a big difference in engine performance, so I want to get it right. ANY HELP WILL BE APPRECIATED!

jrmunn

Re: Setting Simple Ignition Points
 

Not sure, but can you replace it with a cap that has the window? Sounds like you are doing the adjustment correctly but without the window, the re-check and fine-tune becomes the issue as you have stated.
Also you can go point-less and use a Pertronix kit or do the HEI upgrade or find a distributor that has the window.
http://www.pertronix.com/prod/ig/ignitor/default.aspx

http://6066gmcclub.com/gmcguy/hei.html

Re: Setting Simple Ignition Points
 

Does Pertonix make a kit for this? Best solution ever!

Re: Setting Simple Ignition Points
 

I know this question seems too obvious to ask, but I still gotta ask it anyway. When you set the point gap, did you check to make sure that the rubbing block was exactly on one of the high points on the cam? If not, turn the engine BY HAND until it is. DO NOT try to do this with the starter.

Ray

Re: Setting Simple Ignition Points
 

Thank you for the replies. All good points (pun intended). The points that fit my current distributor don't come (that I have been able to find) with an adjusting screw, so a cap window would not help. I agree that electronic is the way to go in the future. This is to solve a current problem. Yes, I make sure the rubbing block is at the high point of the cam, but do this using the starter (another try it again to get it right operation). How do you turn the engine by hand?

jrmunn

Re: Setting Simple Ignition Points
 

Put a big socket/ratchet on the center bolt of the lower pulley

Re: Setting Simple Ignition Points
 

Probably the easiest way to set this kind of points is to run the hold-down screw in until snug, but not fully tight. Use a screwdriver which will bridge the two slots and twist it to set the gap where you want it and then tighten the screw the rest of the way. This is easier to do than the description makes it sound like.

Ray

Re: Setting Simple Ignition Points
 

I'm glad I read this since I haven't messed with a set of points in 20 years. Back then it was dual points...

...I finally pick up my truck tomorrow so I will be dealing with this soon. I plan on "setting" my points into the dumpster just as soon as I can get a HEI for it.

Re: Setting Simple Ignition Points
 

A good video

http://www.youtube.com/watch?v=Y9wZvcr3v2c

Re: Setting Simple Ignition Points
 

Good maybe for someone who has already done the job before. However, I was quite surprised when our Australian friend failed to mention that the rubbing block has to be on one of the high points of the cam when setting the gap. A first-timer might not necessarily be aware of this most important detail.

Ray

Re: Setting Simple Ignition Points
 

Of course you are correct Ray. That oversight was mentioned in the video comments as well. Setting the rubbing block to a high point is more implied earlier on in the video but not directly stated.

Re: Setting Simple Ignition Points
 

Thank you all for the suggestions! I will try again. This time turning the engine by hand and using a screwdriver in the slots to move the points spacing. The video is also helpful, but I would not have had a problem in the first place with that much room to work. Working on a distributor at the back of the engine while balancing on a fender and looking around wires and other parts to see the points, plus trying to place and use a screwdriver, adds much to the challenge of getting the setting right. HEI sounds good, but I am not sure it really adds enough to a low rpm engine at a cost of at least $200 plus different wires and coil compared to $7 for points that should last through at least five oil changes. The igniter route sounds like a more economical way to avoid changing points. Maybe next time. Now it is time to get back to the truck and finish this so that I can move on to learning how to adjust the clutch.

jrmunn