Video on "How to set points and timing on classic GM cars".

[Hazdaz]

 

He uses his 2nd gen Riv to show how to set points and timing.  Might come in handy for some. 

[RivNut]

How does he get a good ground if the radiator hose clamp he connects to is insulated by the rubber hose?

[NTX5467]

The same way that magnetic resonance is transferred from the engine to the heater core on some Park Avenues at a particular rpm, making the heater core huuummmmmmm.  Buick TSB on that!

[NTX5467]

NOT to take away from the video, but the 1957-way was to raise the door, insert an Allen wrench, index it to the nut inside, then turn it CCW until the engine misfires.  Note the position of the wrench's short side.  Turn the wrench CW until the engine misfires, noting the position of the wrench.  Turn the wrench to the 1/2 way point between the misfire points.  Done.  No meters or grounds involved.

 

I read that in a book published back then, well before dwell/tachs were commonly available, when they were still only in the larger shops or at dealership shops.  I thought that was pretty neat!

 

Enjoy!

NTX5467

[rocketraider]

Probably a good thing to learn, because unless you have your own dwell tach/analyzer and timing light, odds are against finding a shop who has them or knows how to use them.

 

I've got to where if I find them at an auction, estate sale or flea market and they look like they've been reasonably well cared for, I'll take a chance if I can get it cheap. Been lucky. They've all worked.

 

Worst thing has been finding the manuals for a couple of them. If you can't find the exact manual you can usually find one maybe one model number off that will work.

 

One of my recent successes has been teaching a 21 year old to set timing on his 1985 Dodge truck. Don't know who got the biggest kick from that, me or the boy!

[Hazdaz]

19 minutes ago, rocketraider said:

 

I've got to where if I find them at an auction, estate sale or flea market and they look like they've been reasonably well cared for, I'll take a chance if I can get it cheap.

 

No idea how well they would work, but doing a quick search on Amazon and it looks like Dwell meters can be had for as little as $25 or so, and apparently some regular multimeters have a dwell setting (but I assume most don't). 

[NTX5467]

Most of the tachs had dwell scales at their bottom scale, usually. But always look.

[rocketraider]

8 hours ago, Hazdaz said:

No idea how well they would work, but doing a quick search on Amazon and it looks like Dwell meters can be had for as little as $25 or so, and apparently some regular multimeters have a dwell setting (but I assume most don't). 

Digital ones will usually measure dwell since they were used to check dwell (!) on electronic QuadraJets.

 

I'm partial to my old analog stuff though. I have a Fluke DVOM but my old Archer analog multimeter and the analog Sears engine analyzers are just comfortable in my hands.

 

I realize some of the video was basically show and tell, but I was taught to always disconnect and plug the distributor vacuum advance source, and to use the manufacturer's idle speed settings so as to not introduce vacuum or unwanted mechanical advance into base timing settings. Most factory CSMs have distributor mechanical advance specs.

 

I'm willing to bet I'm not the only one who ever got zapped setting dwell on a GM window distributor either!⚡😳😬🤯

 

There was a reason for that odd-looking points setting tool...

 I finally broke down and bought one of these off the tool truck. It wasn't cheap but it beat the life out of messing with an Allen wrench or one of those flexible shaft jobs. It would adjust idle mixture screws too. I didn't get shocked or burn my fingers anymore once I had it.

 

[XframeFX]

I borrow from Guys at Car meets. My old school instruments consist of a fussy xenon bulb in my timing light and 20% functional Sears Dwell/Tach meter🆖. I cut the test lest leads off the latter and chucked it last month.

 

I'd really like a dial back timing light with tachometer so I could enter advance values in my XLS to generate a chart. Borrowed instruments work but are also old school analogue.

Only about $150 for this Innova 3568 but can't justify it at the moment😞:

https://www.innova.com/products/digital-timing-light-3568a

 

[RivNut]

Click on the Amazon link. $77 and change. Free shipping if you're an Amazon Prime member.

[1965rivgs]

6 hours ago, rocketraider said:

Digital ones will usually measure dwell since they were used to check dwell (!) on electronic QuadraJets.

 

I'm partial to my old analog stuff though. I have a Fluke DVOM but my old Archer analog multimeter and the analog Sears engine analyzers are just comfortable in my hands.

 

I realize some of the video was basically show and tell, but I was taught to always disconnect and plug the distributor vacuum advance source, and to use the manufacturer's idle speed settings so as to not introduce vacuum or unwanted mechanical advance into base timing settings. Most factory CSMs have distributor mechanical advance specs.

 

I'm willing to bet I'm not the only one who ever got zapped setting dwell on a GM window distributor either!⚡😳😬🤯

 

There was a reason for that odd-looking points setting tool...

 I finally broke down and bought one of these off the tool truck. It wasn't cheap but it beat the life out of messing with an Allen wrench or one of those flexible shaft jobs. It would adjust idle mixture screws too. I didn't get shocked or burn my fingers anymore once I had it.

 

 I'm a retired tech and I have had the same tool for decades and it has come in handy very often....easy to rationalize the cost if using it to make a living!

Tom Mooney

 

[1965rivgs]

4 hours ago, XframeFX said:

I borrow from Guys at Car meets. My old school instruments consist of a fussy xenon bulb in my timing light and 20% functional Sears Dwell/Tach meter🆖. I cut the test lest leads off the latter and chucked it last month.

 

I'd really like a dial back timing light with tachometer so I could enter advance values in my XLS to generate a chart. Borrowed instruments work but are also old school analogue.

Only about $150 for this Innova 3568 but can't justify it at the moment😞:

https://www.innova.com/products/digital-timing-light-3568a

 

  After I bought a dial back timing light I wondered why I hadn't done so sooner. Great tool!

Tom Mooney

[NTX5467]

To me, a dial-back timing light has many uses other than just setting the base timing.  Much better than an old timing tape on the balancer (when that was "high-tech") or making other marks on the balancer and trying to make sure they were accurate.

 

Some claim only the newer, digital dial-back units are accurate, but my old Sears dial-back unit never had any issues.

 

Enjoy!

NTX5467

[gungeey]

To each their own, never looked for a casting or stamped number to find the No1 cylinder. Seems like using a cast number on an intake manifold could lead to trouble. Every V8 I've ever had it was the front piston on the forward cylinder bank. Also, manuals have a chart with the cylinder layout, distributor rotation direction, firing order, idle speed.. right where I'd be verifying point setting, spark plug gap, dwell readings. I do lots of things different than the average bear🐻

[rocketraider]

1 hour ago, NTX5467 said:

Some claim only the newer, digital dial-back units are accurate, but my old Sears dial-back unit never had any issues.

Those are the same people who insist an old car has to have an LS engine swap and 4-wheel disc brakes with ABS to be drivable.

 

My Sears dial-back is dead-nuts accurate. If base timing is, say 10°BTDC, rotating its dial to 10 puts the flash right on 0°.

 

Digital isn't the answer to everything. Especially if the one babbling about how great digital is doesn't know how to interpret or what to do with his digital information.

 

A lot of people never learned to interpret readings on these, either. But the ones who did could work magic! I loved the one my auto-tech school had.

[XframeFX]

2 hours ago, NTX5467 said:

my old Sears dial-back unit never had any issues.

Yes but, having RPM values along with degrees advance helps charting it out. I too did a DIY tape on my harmonic balancer, uh . . . . prefer a digital readout!

[NTX5467]

One advantage, "digital" can't get "parallax", if that matters.  "Analog" means you have to really know how to do something right, in so many cases.

 

As to digital displays, how do you know when that last digit is rounded-up to the next digit?  Is it like .449=.50 or .499=.50?  When a meter scale could allow the user to make that determination.  Not knowing how that is done on a digital read-out, I prefer a meter with a needle.  And a thin needle on a good meter scale.  FWIW

 

Enjoy!

NTX5467

[60FlatTop]

22 hours ago, NTX5467 said:

Turn the wrench CW until the engine misfires, noting the position of the wrench.  Turn the wrench to the 1/2 way point between the misfire points.  Done.  No meters or grounds involved.

That is how they calculated what the dwell and gap should be. Then put it in the specs.

[rodneybeauchamp]

On 10/24/2023 at 1:09 PM, rocketraider said:

 

I realize some of the video was basically show and tell, but I was taught to always disconnect and plug the distributor vacuum advance source, and to use the manufacturer's idle speed settings so as to not introduce vacuum or unwanted mechanical advance into base timing settings. Most factory CSMs have distributor mechanical advance specs.

 

 

 

 

 

Something I also noticed that should always be done is to plug the vacuum leak. I made up a short hose section with a ball bearing in one end to fit over the carburettor vacuum port. And the factory settings are there for a reason.

 

One thing that would have helped explain things much better for newbies would be to have a spare distributor set up in a vice less the cap and showing what the adjustment with the Allen wrench does to the point gap. The narrator seemed to gloss over that part which is critical to understanding what is happening beneath the cap.

 

Also showing and explaining with the dwell meter how closing the point gap INCREASES the dwell setting and opening the point gap REDUCES the dwell setting would also help understanding.
 

Just my thoughts on how it could have been a more informative demonstration.

 

Rodney 😀😀😀😀😀

Edited October 25, 2023 by rodneybeauchamp
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