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73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: JohnnyPopper on January 08, 2021, 10:41:19 PM

Title: Manual contact points adjustment using a Dwell Meter
Post by: JohnnyPopper on January 08, 2021, 10:41:19 PM
While I know many have moved on from archaic contact points to HEI, some pry use the 'original' for their own reasons.

I was in comms with a fellow SQBDY enthusiast and remembered something that might be helpful to those purist.

My first auto shop experience was to adjust the points on my first truck, '57 Apache 235 Inline 6, a major PIA!!! Back breaking leaning 3 feet into the engine well with a feeler gauge and a screwdriver. I'm sure many of you too have experienced the pain... >:(

For those who have the famous GM adjustable points, this won't be helpful... just saying.

For some too young to be aware, contact point adjustment was crucial to your ignition and engine performance. "Dwell" as in dwell meter refers to time, measured in degree (out of 360 degrees of distributor rotation) that the points 'dwell' closed, or in contact. This allowed the DC current to go to the coil, building up in the coil. (for the more learned among us KISS) When the points opened, the pent up energy in the coil flies out of the coil to the center of the dist cap, looking for Ground. At that point it travels across the rotating rotor, and at 15,000 volts, it jumps to the lug inside the dist cap where the spark plug wire is attached. "Houston, we have ignition". Just below the speed of light, or 186000 miles per SECOND.

So thinking back to when I used to work out of a truck that had manual points, I remembered a method I developed to get my points adjusted perfectly every time. I can't say that I originated it, but perhaps I had an original thought on my own.

For some reason, I looked at the dwell meter when i turned over the motor with the ignition disabled, cap off, or something. It registered a reading that was constant, though incorrect. The fact that it was constant was the "light" that went off in my head.

If you can trust that constant as stable, you can use it to adjust your points perfectly.

I set my point gap using a feeler gauge and say, it need to be 32 degrees. When I started the engine, the dwell meter said it was 36 degrees. Off by 4 degrees.

I took the dist cap off, rotor, and then turned the motor over, the dwell meter read 20 degrees.

Then, with the point assembly loose enough to adjust, as I turned the motor over and saw 20 degrees, I move the points where it read 16 degrees and locked it down.

Reassembled the ignition system, started the engine and had a perfect 32 degrees.

Side note: if you have your engine dwell set correctly as well as timing, you will never have to adjust your timing. Your dwell setting, if constant, will keep your timing constant.

IMHO, this advice is practical as well spiritual, in that "you are dwelling with them according to knowledge" 1 Peter 3:7
If you have one, give your wife or husband a kiss and tell them you love them based on "knowledge".

 
Title: Re: Manual contact points adjustment using a Dwell Meter
Post by: carmen77 on January 15, 2021, 02:08:35 PM
JP,

Lucky for me I have someone very smart who taught me all about the Dwell device and itís purpose!

Thank you for sharing this with everyone. Great knowledge and great advice...as always!


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Title: Re: Manual contact points adjustment using a Dwell Meter
Post by: JohnnyPopper on January 15, 2021, 02:49:14 PM
Carmen, you are too sweet! After sharing that with you, I thought others might benefit. Thanks!!
Title: Re: Manual contact points adjustment using a Dwell Meter
Post by: carmen77 on January 15, 2021, 02:58:12 PM
Any advice from you is sound advice thatís for sure!

I learn lots from you and appreciate your willingness to share and teach.


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Title: Re: Manual contact points adjustment using a Dwell Meter
Post by: Mike81K10 on January 15, 2021, 04:39:35 PM
Was thinking a few days ago about how many today probably never experienced dealing with changing out the points, Condenser, and Coils in vehicles, since most have only seen HEI distributors. My early years was with vehicles using points. Then again, wheels were wheels, tires were tires, and rims where rims, such as the beauty rims on my rally wheels in the attached pic. Now days, many refers to wheels as rims and have no idea what a rim really is.
Title: Re: Manual contact points adjustment using a Dwell Meter
Post by: carmen77 on January 15, 2021, 04:50:12 PM
So true about the rims.
Kids these days....am I right? Lol


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Title: Re: Manual contact points adjustment using a Dwell Meter
Post by: zieg85 on January 15, 2021, 06:30:53 PM
Neighborhood tune up weekends, what a 8 year old kid interested in cars longed for.  This was in the early 70's.  I still have my dad's Niehoff matching timing light and tach and dwell meter.  Thanks for a trip down memory lane.
Title: Re: Manual contact points adjustment using a Dwell Meter
Post by: JohnnyPopper on January 18, 2021, 04:14:49 PM
Neighborhood tune up weekends, what a 8 year old kid interested in cars longed for.  This was in the early 70's.  I still have my dad's Niehoff matching timing light and tach and dwell meter.  Thanks for a trip down memory lane.

Now THAT sounded like a lot of Fun!

Mike those wheels look great! Do you have any spares?
Title: Re: Manual contact points adjustment using a Dwell Meter
Post by: Mike81K10 on January 18, 2021, 07:23:10 PM
They are used OEM wheels JP that I bought from a person out of TX that my brother knew from swap meets. I can probably give you his info if you need some wheels. He media blasted them and painted them and they came with the beauty rims and centers for $450. My brother brought them to me (in AL) for a visit last week. I have got some Argent Silver Paint and 2K satin clear that I am going to use to repaint them with prior to mounting. Don't feel the paint that is on them is of the quality I like (perhaps I am picky), but they are in great condition (all are 15x8).
Title: Re: Manual contact points adjustment using a Dwell Meter
Post by: zieg85 on January 18, 2021, 08:13:01 PM
Neighborhood tune up weekends, what a 8 year old kid interested in cars longed for.  This was in the early 70's.  I still have my dad's Niehoff matching timing light and tach and dwell meter.  Thanks for a trip down memory lane.

Now THAT sounded like a lot of Fun!

Mike those wheels look great! Do you have any spares?

Oh it was, One neighbor had a 71 GMC Sprint while the other had a 60's Dynamic 88 and my dad a 67 Ford Custom.  All with points/plugs and condenser.  All the other neighborhood kids were playing basketball while I was learning away
Title: Re: Manual contact points adjustment using a Dwell Meter
Post by: Mike81K10 on January 18, 2021, 09:11:29 PM
zieg, wish we could get the youth of today to learn how to work with their hands on vehicles, carpentry, welding, and other things. So many wants to stay indoors playing games and many schools push colleges and universities when there is good money in mechanics, welding, and other hands on jobs, not to mention the job security in those kind of jobs. The local mechanic shops in my area are in desperate need of mechanics.
Title: Re: Manual contact points adjustment using a Dwell Meter
Post by: JohnnyPopper on January 19, 2021, 08:22:10 PM
Sounds like my 13 yo grandson.

I did offer to take him shooting my ancient Crossman 600 semi-auto 22 cal. Pellet pistol. CO2, 10 shots in 3 seconds, still very dangerous.

He perked up...we'll see.  ::)
Title: Re: Manual contact points adjustment using a Dwell Meter
Post by: carmen77 on January 19, 2021, 08:25:43 PM
Johnny,

If you get him to go...he will love it!


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Title: Re: Manual contact points adjustment using a Dwell Meter
Post by: JohnnyPopper on January 19, 2021, 10:59:27 PM
I agree, Guy thing= blowing up stuff. (sexist?  ::) )

I gave up hunting about 35 years ago so we won't be killing anything.

Funny, when I used to work in/on residential systems, I would always ask the Senior Citizens if they had any old airguns laying around. That's where I found "Mr. Blasto" and other unnamed species. The reason he got the moniker is it Scared the crap out of me the first time I turned him loose.  :o
Title: Re: Manual contact points adjustment using a Dwell Meter
Post by: carmen77 on January 19, 2021, 11:04:56 PM
Johnny,

I love blowing stuff up and shooting. So girls can love it too.

I also used to hunt when I lived in Michigan and I also like to go fishing. I admit I donít like to put on the bait or take the fish off so really I just love casting and catching. Lol

It sounds like you have some fun stuff


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Title: Re: Manual contact points adjustment using a Dwell Meter
Post by: JohnnyPopper on January 19, 2021, 11:07:33 PM
For a gal whose friends are all men, I knew you would get me up to speed on your status... ;)
Title: Re: Manual contact points adjustment using a Dwell Meter
Post by: carmen77 on January 19, 2021, 11:13:33 PM
Guys just do more interesting and fun stuff. 

The other square body gals would likely agree that playing with trucks and shooting guns is much more fun than shopping or getting your nails done. at least for this gal it is. lol


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