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Using modern technology on older Buicks


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Interesting when you try to adapt new technology to older vehicles.

 

My faithful 20 year old Optilux timing light, dwell meter, tachometer and volt meter decided to fail some time ago (strobe light stopped working) l and I could no longer buy a replacement xenon globe. So I went and bought a nice professional timing light with digital readout and everything ( except it won’t make coffee) .Picture of the culprit below! Used it on a ‘63 Buick Riviera when it arrived and it worked fine. 😀😀😀😀

 

Well I decided to set the timing and dwell on my 1938 Buick Special, hooked it all up to a 12V supply and all I got was 45degrees of dwell regardless of what I adjusted the contacts to. Every reading, 45 degrees. 🤔🤔🤔🤔🤔

 

I hooked it up to my 1963 Buick Riviera and got a reading of 28 degrees which is close to factory setting of 30 degrees. So it’s working, but not on my ‘38.  I had a older style Engine Analyser similar to the photo below at I got at a recent swap for $5.00 and hooked that up and it showed proper readings as I adjusted the dwell (point gap). Got it set to 30 degrees and it starts easily. 😀😀😀😀😀

 

OK, so much for technology!
 

After much frustration, I discovered in the user guide (from another supplier) that the solid copper wire leads I use on the ‘38 give off too much EMF, UHF, ABC or some other frequency that makes the modern unit go to a fail safe mode. You need to substitute number one spark plug lead for a resistor type unit to read the dwell properly.

 

I think I’m going to rely on my $5.00 swapmeet unit for the ‘38 Buick as changing a plug wire on a ‘38 is not a two minute job.

 

A trap for young players and hope it helps others.

Rodney 😀😀😀😀😀😀

 

 

4D02409B-4A41-44AD-8DDA-0077113D9C27.png

43827397-D7A1-41A1-80DE-03439E9E4795.jpeg

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Rodney, 

     Did you connect a ground wire from the car ground (6 volt) to the 12 volt power supply ground that is powering the light.    I had to do that to get my 12 volt diagnostic equipment to read my 6 volt Buick.   Hugh

Edited by Hubert_25-25 (see edit history)
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On 3/5/2020 at 12:55 AM, Hubert_25-25 said:

Rodney, 

     Did you connect a ground wire from the car ground (6 volt) to the 12 volt power supply ground that is powering the light.    I had to do that to get my 12 volt diagnostic equipment to read my 6 volt Buick.   Hugh


Hugh,

I did not think to do that. Next time I use the meter I will give it a try. Really would like to use it, but if it means replacing the original spark plug lead with a resistor type,  it may not happen as it means removing the side cover.  But I will try it and report back.

cheers

Rodney 😀😀😀😀😀😀

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  • 2 weeks later...

Dwell depends on number of cylinders.  Dwell is the amount of time or degrees of the distributor shaft that allows the points to remain closed.  On technical theory, a 4 cylinder engine it would be 90deg.  That is 360 degrees in a circle divided by 4 = 90.  6 cylinder = 60 degrees, and 8 cylinder = 45 degrees.  

 

In a dynamic system with points, the dwell is usually less.  Frequently for most Buick engines, it is about 30 degrees.  These numbers allow for the ramp up and down of the point rub block on the cam on the distributor shaft when the point contacts are not completely closed. 

Edited by Larry Schramm (see edit history)
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On 3/16/2020 at 12:08 PM, Larry Schramm said:

Dwell depends on number of cylinders.  Dwell is the amount of time or degrees of the distributor shaft that allows the points to remain closed.  On technical theory, a 4 cylinder engine it would be 90deg.  That is 360 degrees in a circle divided by 4 = 90.  6 cylinder = 60 degrees, and 8 cylinder = 45 degrees.  

 

In a dynamic system with points, the dwell is usually less.  Frequently for most Buick engines, it is about 30 degrees.  These numbers allow for the ramp up and down of the point rub block on the cam on the distributor shaft when the point contacts are not completely closed. 


Buick and other manuals list 31 degrees. It now seems to start easily and runs smooth set at that. And peace of mind knowing it’s set right!

Rodney 😊😊😊😊😊😊😊😊

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Larry S is on the right track but the actual dwell is about half those numbers when you allow for and subtract for the amount of rotation the points are also open on each lobe. 

Edited by Brian_Heil (see edit history)
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Also, with our older engines that often have worn distributor lobes, the correct point gap does not translate to the correct dwell.  A dwell meter when used correctly will result in the correct dwell. 

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On 3/17/2020 at 10:46 PM, Brian_Heil said:

Also, with our older engines that often have worn distributor lobes, the correct point gap does not translate to the correct dwell.  A dwell meter when used correctly will result in the correct dwell. 


Brian,

totally agree! I know how to use a feeler gauge properly now, but much prefer the accuracy of a dwell meter. I think I got spoilt a long time ago when I had my first Buick V8 with Allen key adjustment and found how easy and accurate it was with the dwell meter.

Rodney 😀😀😀😀😀😀😀😀

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12 hours ago, rodneybeauchamp said:


Brian,

totally agree! I know how to use a feeler gauge properly now, but much prefer the accuracy of a dwell meter. I think I got spoilt a long time ago when I had my first Buick V8 with Allen key adjustment and found how easy and accurate it was with the dwell meter.

Rodney 😀😀😀😀😀😀😀😀

 

Allen key????  I have not found a place to put an Allen key on any of my old Buicks.  To set the dwell on my '15 truck, you take off the distributor cap, remove the rotor, and with a feeler gauge and screw driver adjust the gap.   

 

Since you are there with the rotor off to set the timing, there is a screw in the center of the distributor shaft accessed from the top of the shaft where the rotor is.  Loosen the screw and put the rotor back on and move the rotor to where you think the timing should be. Remove rotor tighten the screw and reassemble the distributor.  Check timing if you want with a light.  If not where you want it, take the distributor cap off, rotor off and re do the process again until you get the timing where you want it.  

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On 3/17/2020 at 5:16 AM, Brian_Heil said:

Also, with our older engines that often have worn distributor lobes, the correct point gap does not translate to the correct dwell.  A dwell meter when used correctly will result in the correct dwell. 

If one is fortunate enough to have a dwell specification, set the points to whatever gap is necessary to achieve the specified dwell.  The proper dwell is what makes the car run right, and specified point gap is the mechanical expression of the  specified dwell when the distributor is NEW.  As Brian Heil said, worn lobes will change the gap needed to achieve the specified dwell.  I learned that in the early 1960s while tuning a newly-acquired 1950 Pontiac 6 with 90+k miles.  When I set the points to spec (seems it was about 0.020), the engine barely ran and the dwell was way off.  I think I had to reduce the point gap to about 0.014 to get the specified dwell, at which point the engine ran well.

 

If your car is old enough that there are no published dwell specs, I suggest setting the points on the smaller end of any specified gap range and see how it runs.  You might need an even narrower gap.

Edited by Grimy
rephrased a bit to be more clear (see edit history)
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Larry S.  just detailed the process I will go through when I set the Starter/Generator unit back in place on my engine.  That will get things close enough to be able to start the engine and then go from there.

 

Terry Wiegand

South Hutchinson, Kansas

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On 3/20/2020 at 9:21 PM, Larry Schramm said:

 

Allen key????  


Not sure when GM patented it but guessing the early 60s?

 

GM points have an Allen adjustment and a little door you flip up on the cap to access it. 
 

With the engine running and the little Allen wrench through the little door in the cap  on the points you fine tune your dwell with a meter.  
 

Here’s a pic with the cap off. 

DA7A5D79-12BA-460A-856D-C009BD3A1000.jpeg

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On 3/22/2020 at 7:52 PM, Brian_Heil said:


Not sure when GM patented it but guessing the early 60s?

 

GM points have an Allen adjustment and a little door you flip up on the cap to access it. 
 

With the engine running and the little Allen wrench through the little door in the cap  on the points you fine tune your dwell with a meter.  
 

Here’s a pic with the cap off. 

DA7A5D79-12BA-460A-856D-C009BD3A1000.jpeg

 

Brian,

I would guess that is about right time for the allen key adjustment.  Remember doing that on my '63 Skylark with the 215 aluminum V-8 engine.   Worked slick.

 

 

Edited by Larry Schramm (see edit history)
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I have another distributor and a late set of points! I might see if they fit, wouldn’t that be a solution to an age old problem.

will get back with the results soon!

Rodney 😊😊😊😊😊😊😊

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