cjmarzoli

1931 Dual Point Timing- Advice?

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If for some reason the advance unit went to full advance when you were trying to adjust secondary points with the Syn 6 marks lined up the rotor would be past or near past terminal 6 on the cap.  That's probably wishful thinking but possible.  As far as the springs being weak the only real way to test is with a distributor machine.  My experience is if the original springs are taut enough to install over the spring posts on the advance rotor and flyweights with flyweights all the way collapsed in and no slack between spring end and groove in the post that's pretty normal.  They are very weak springs at best because the distributor rotates half engine speed and the advance unit is supposed to start at 10-14 degrees at 800 crank or 400 distributor shaft speed, 19-23 at 1800 crank/900 distributor and is fully advanced at 30-34 degrees at 3000 crank or 1500 distributor speed.  Keep in mind 34 is the total advance including the initial advance you dial in using the flywheel marks with engine stopped.

 

One other thing to try if you are game.  Someone mentioned the fact that if there is a mis match of points to the distributor THAT could affect the geometry and cause the secondary points not to be capable of being synchronized at the Syn 6 mark.  Do you know for sure that the distance from the pin the movable point pivots on to the center of the contact point on the movable point is equal for both primary and secondary movable points, I.E. are the arms the same length?  The point bases should also be symmetrically opposite each other.  If you took both bases off and matched up the bottom plates of the stationary point bases all the adjustment holes should line up perfectly.  If not you have the wrong point base on one of the point sets.  The bases should match perfectly.     

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OK I do not have a chance to look at my 32 but I am going to ask this anyway at the risk of sounding stupid. 

The eccentric screws used to adjust the points. Can they be installed improperly?  Basically 180 degrees off.

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Posted (edited)

I tried posting this once earlier but I did not see it show up. So here I go again.

I do not have my 32 Buick in front of me right now but can the eccentric screws used to adjust the points be installed 180 degrees off. This is the only thing I can think of that can alter the position of the point set.

Sorry for the repost

.

Edited by CTCV
sorry for the repost (see edit history)

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I found my old before and after pics. After rebuilding and setting the gaps it was installed. I only rotated the engine to see if the timing looked correct. It looked right so we cranked it . Had to turn to the most retarded position and it started right up. Maybe the images can help.

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I can't remember.... but it seems to me the eccentric brass screws just turn 360o to take the right position to set the points. If the points aren't synchronized and you can't synchronize them, are the rubbing blocks too far from the pivot? But it started. So does the question still apply?  I am puzzled now.

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I am using the image from cjmarzoli.

I believe the eccentric screws can limit the adjustment if not in the correct orientation to each other. Imho. See image.

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Posted (edited)
10 hours ago, Spinneyhill said:

I can't remember.... but it seems to me the eccentric brass screws just turn 360o to take the right position to set the points. If the points aren't synchronized and you can't synchronize them, are the rubbing blocks too far from the pivot? But it started. So does the question still apply?  I am puzzled now.

I don't think the rubbing blocks to pivot distance is the issue. I think the points set plate needs to move counterclockwise in relationship to the shaft. The rubbing blocks are in the wrong position but only because the plate and pivot are in the wrong position. If I were to suggest that the rubbing block for set 1 is at 12 oclock, the rubbing block for set 2 is at 7 oclock. It needs to move more towards 630. It cannot get there with the eccentric screws binding each other. In the rusty pic of my distributor you can make out what I feel is the correct eccentric screws orientation.  Again just MHO

Edited by CTCV
added info (see edit history)

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I'm going to respectfully disagree that the 2 eccentric screws can bind each other.  The eccentric screws are riveted to the plates allowing them to rotate 360 degrees.  The eccentric screw that adjusts the point clearance on the movable plate (the one you synchronize to #6 cylinder) is riveted to the MOVABLE PLATE.  The other eccentric screw that you use to adjust timing of the movable point to synchronize it to cylinder #6 is riveted to the BASE PLATE beneath the movable plate. 

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Posted (edited)
24 minutes ago, Str8-8-Dave said:

I'm going to respectfully disagree that the 2 eccentric screws can bind each other.  The eccentric screws are riveted to the plates allowing them to rotate 360 degrees.  The eccentric screw that adjusts the point clearance on the movable plate (the one you synchronize to #6 cylinder) is riveted to the MOVABLE PLATE.  The other eccentric screw that you use to adjust timing of the movable point to synchronize it to cylinder #6 is riveted to the BASE PLATE beneath the movable plate. 

In cj's image please note the position of the locking screws compared to the slot they are in. The plate is maxed out with the screws at the end of the travel of the slot. If cj can loosen the locking screws and rotate the base plate (of the point set) to the opposite ends of the slots I would agree with you. My guess he cannot until he lifts the plate, then rotated the eccentric screw closest the pivot 180 degrees and reinstalls the plate.

When I say "plate" I am referring to the points set base plate. Sorry for any confusion.

Edited by CTCV (see edit history)

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Thanks to all who replied.  I have my timing set correctly now thanks to your tips.   The use of a test bulb connected in line is essential to determining the exact point at which points open.   My main issue was I had set the primary points (cyl #1) by eye and it was a bit off, which thru the position of the secondary points off.  Also, not mentioned in the manual- it is essential to adjust the plate for the secondary points all the way counter clockwise before adjustment so there is “room” to adjust them clockwise with the eccentric screw.  Once I did these two things it was relatively easy to get them synchronized.   It is running much better now but starving for gas going up hills or under load so I am presently rebuilding the carburetor.

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3 hours ago, cjmarzoli said:

Thanks to all who replied.  I have my timing set correctly now thanks to your tips.   The use of a test bulb connected in line is essential to determining the exact point at which points open.   My main issue was I had set the primary points (cyl #1) by eye and it was a bit off, which thru the position of the secondary points off.  Also, not mentioned in the manual- it is essential to adjust the plate for the secondary points all the way counter clockwise before adjustment so there is “room” to adjust them clockwise with the eccentric screw.  Once I did these two things it was relatively easy to get them synchronized.   It is running much better now but starving for gas going up hills or under load so I am presently rebuilding the carburetor.

Great to hear of your success. As far as the fuel shortage I have read where owners were installing electric fuel pumps as an assist to the original. They also highly recommend the installation of an inertia switch to shut of the pump in an accident.  They are available in 6 volt. 

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Great to hear of your success and I can second your observation that you would have a hard time setting point clearance or break point by eye.   I also disconnect the condenser and coil wires from the point circuit while setting break point.   I use a Fluke volt/ohm meter to determine the break point which is much easier to see with condenser out of the circuit.

 

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Good stuff,  just for grins I ran a timing light and checked to see how close I was, The light worked great on a seperate 12v source. CTCV I can send a pix of my distrib if that helps.

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After initial setting with a test lamp, i did connect my timing light to it while it was running.  My light is inductive and goes around the spark wires and it seemed to power fine of the 6v battery in the car.    According to the light the marks were very close to where they should be.

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On Thursday, August 08, 2019 at 2:42 AM, Steves Buick said:

Good stuff,  just for grins I ran a timing light and checked to see how close I was, The light worked great on a seperate 12v source. CTCV I can send a pix of my distrib if that helps.

Hi Steve, 

Mine is up and running but in the school and we were off for the summer and I could not go in to look at it. I was going from memory and some pictures I had taken earlier. For some reason I thought I remember having an issue with mine until those eccentric screws were in the proper position. 

I would absolutely welcome a picture ,, I enjoy seeing others work.

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One other issue of note while timing:  Depending on your vantage point, where the timing marks fall on the bell housing change quite a bit.  If you are standing up over the mark and get it lined up and then kneel or lower your vantage point. the line on the flywheel "moves up" visually as you lower your eyes.   Depending on how high or low your head is, this can make quite a difference. Does anyone know the recommended eye position for performing this task?  I ended up doing it by setting my eye level as close to the level of the index mark on the bell housing as possible.  I basically set my chin on the splash apron.

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I suspect if you got your drafting board out and laid out the opening of the housing casting  over the flywheel, then developed the maximum possible parallax by drawing lines from the index mark on the housing tangent to the top and bottom edges of the housing opening closest to the flywheel and intersecting the flywheel then mathematically calculated the possible error in degrees by dividing the distance between the points where the lines of parallax intersect the flywheel into the circumference of the flywheel you would find a possible error of +/- a degree or 2.  You would have to sight the cylinder 1 timing mark at one of the worst possible angles then sight the cylinder #6 timing mark at the opposite worst angle to make that large an error in point synchronization and assuming you viewed both marks from the same position you could only be off on absolute timing by half the possible error you developed mathematically.  If you are really worried about parallax effect on absolute timing why not make a pointer that can be attached to the housing aligned with the index mark on the housing then bent into the opening on the crank centerline so it is within a 1/16" of touching the flywheel?  That would eliminate the parallax issue altogether.  If you take reasonable care to stand so you are looking from the same place each time you line up the marks you will be close enough on point synchronization even if you are a little off on the absolute timing.  There is probably enough lash in the gears, shafts and bearings involved to cause a larger error in absolute timing than the parallax  will cause. 

Edited by Str8-8-Dave
add text (see edit history)

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