ignition issue

5

'51 Special

Active Member
I just completed rebuilding the 263 in my '51 Special. It was running just before teardown. I re-installed the original distributor (Delco-Remy 1110815), and a new coil that had only minutes of use before the teardown began (I wanted to make sure it would run before tearing into it, and I had not been getting any spark). Now, again, I cannot get any spark. (Not weak spark, but NO spark.) I tried another coil, still no spark.
The distributor and all of its parts are clean and dry. The points are used but in excellent condition, and correctly gaped. The primary circuit and the points are working right, the rotor and cap look good and worked fine before teardown.
Part 1-49 of the 1951 Buick Shop Manual, in subparagraph b.2., describes this coil test for the secondary circuit: "Apply one test point to the high tension terminal, and the other test point to one of the primary terminals. If the secondary circuit is not open, the lamp will not light but tiny sparks will appear at the test points when they are rubbed over terminals. If secondary circuit is open, no sparks will occur."
When I do this, I get no "tiny sparks." Same with both of the coils I tried. I can't believe that every coil I get my hands on, new or old, has a bad secondary winding, including the one that ran this engine just before I shut it down for the rebuild. I don't have a coil tester.
Anyone have any idea what is really going on here?
 
Coils almost never go bad unless they are seriously abused, so don't worry about a coil tester. Instead, let's check the obvious stuff first.

I know you said the primary circuit is "working right", but please humor me on this. Turn on the ignition switch and turn the engine by hand until the points are open. Now check for power at both the (+) and (-) terminals of the coil. Do you have power at either one? If no, check all the way back to the switch, because you have a break in the wiring somewhere.

If you have power at (+) but not at (-), disconnect the lead going to the distributor. If you have power at (-) now, you have a short to ground somewhere in the distributor or the connecting wire.

If power at both (+) and (-), turn the engine by hand until the points are closed. Now you want to see power at (+), but not at (-). Are you seeing where this is going? After you run those tests, please post back here with what you find.

Lastly, are are you still running on 6 volts or have you converted to 12 volts? Also, are there any other modifications to the car's electrical system which you may not have mentioned?

Ray
 
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Ray-
I followed your directions. The second one led me to a short. I can't be absolutely sure, but it appears to have been in the connection from the coil through the side of the distributor. I disassembled the post, cleaned the theads and post, and had no short when that was done. (Though it is possible the short was through the I just moved a wire inside the distributor when I was doing that.) In any event it now has a hot spark.
Your directions were clear, simple, and easy to follow, and I am greatful for your valuable information and quick response.
Another question. I thought I had read a post on this site identifying a rebuilder of distributors with a good reputation for making modifications apprporpriate for modern gasoline, but I cannot find it. My distributor has likely had nothing but new points/condensors/rotors/caps since it was built. Any recommendations or other suggestions? I currently have access to ethenol-free gas, but that may not last long, and ethanol is hardly the only change made to gas in the last 60 years.
 
My favorite stories are the ones with happy endings. I am very glad to hear that you were able to find the problem and that it wasn't difficult to fix. Thank you for the feedback. It may be of help to the next person who runs into a similar problem.

You are right that these engines can benefit from timing changes to take the best advantage of today's fuels. I run more initial advance than stock, but I don't know exactly how much. The timing mark is almost at the edge of the window and I never get any pinging unless I'm not paying attention to what gear I'm in.

Unfortunately, I can't offer any suggestions for a rebuilder, and there was nothing in the links section. Maybe one of the other members will see this and chime in. If nothing turns up here, you might want to look on message boards for other makes of vintage GM cars, as all the Delco distributors from this time period are pretty much alike except for the Chevy 6.

Ray
 
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So, I'm back to this thread. I started the Buick up yesterday, and ran it for awhile to warm it after a long winter's sleep. After about ten minutes, and me thinking I might want to tune the carb, the engine just died. Like I shut it off. I ran through Ray's tests, and found a low-voltage short to ground seemingly existing within the distributor. That is, when I disconnected the wire to the points at the connection from the coil through the side of the distributor, the short disappeared. When that connection was made (and with the points open) the short appeared. By visual inspection, there is nothing about the points or connecting wire to suggest a short. I checked to see if there is a short through the condenser (is that even possible?) and found none. I'm going to find a new set of points and a condenser. But there is also this- even though I seem to have a short within the distributor, at the same time, the accelerator vacuum switch on the carb seems to have stopped working. The starter won't crank with the ignition on and the accelerator depressed. Because this was a Dynaflow car, and now is a three-speed, I connected the engine compartment wire that formerly ran to the neutral safety switch to the accelerator vacuum switch. This was working fine, but something has gone amiss. My question: is this a coincidence, or should I start by looking for ignition switch and wiring problems? '51 Special
 
Remove the stud that goes through the side of the distributor and inspect its insulating bushing and washer for damage. If those parts look good, reinstall the stud without connecting the points and check to see if the stud is shorted to ground. If no short at the stud, check the points for a short to ground without connecting them to the stud. The condenser CAN develop a short, but this is quite uncommon. If you suspect the condenser is shorted, check it independently, That is, with its lead not connected to anything else.

As for the starting circuit, you troubleshoot it in sequence, just like the ignition system. I will get back to that, first I need to know if the car has its original 6V system or if it has been converted to 12V. If 12V, do you have a generator or an alternator? If an alternator, what did you do with the relay lead which formerly connected to the voltage regulator? Lastly, are your relay terminals numbered 1 through 4 as on the wiring diagram?

Ray
 
Ray-
The "terminal stud" that goes through the side of the distributor, its insulating bushing and washer, all appear to be undamaged. And, as I noted, when I disconnected the wire or "terminal connector lead" within the distributor that runs from the stud to the points, the short disappeared. When I reconnected the lead, the short reappeared. I have new points and condenser on order, and am looking for a replacement for the lead as mine is losing its insulation. The connector lead is actually a tiny cable, made of 7 strands of 9-strand wire, with a (once) flexible rubber insulation covered with cloth, and with appropriate connectors for the stud and points crimped on. By eye, the total uninsulated diameter of the wire is about 14 gauge. I have been unable to find any source for a replacement, and am now looking for similarly flexible wire with which to make up a new lead. I am unsure of just how flexible this lead must be. Obviously, it must be able to tolerate a very large number of small movements generated by the advance mechanism, and not materially affect the speed or extent of the advance. Any ideas?
The starting circuit is as original, except the wire that formerly ran to the neutral safety switch now runs directly to the accelerator vacuum switch. I made that change after reviewing the wiring diagram.
'51 Special
 
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'51 Special said:
Ray-
The stud that goes through the side of the distributor, its insulating bushing and washer, all appear to be undamaged. And, as I noted, when I disconnected the wire (within the distributor) that runs from the stud to the points, the short disappeared. When I reconnected the wire, the short reappeared. I have new points and condenser on order, and am looking for a replacement for the internal distributor wire. (Mine is losing its insullation.)
The starting circuit is as original, except the wire that formerly ran to the neutral safety switch now runs directly to the accelerator vacuum switch. I made that change after reviewing the wiring diagram.
'51 Special
Click to expand...

Ok, so your starting circuit is basically all stock, except that you bypassed the NSS.

Turn on the ignition and check for voltage at both terminals of the carb switch. You want to see voltage on one of them. If no voltage on either, you have a break somewhere between the ignition switch and the carb. Go back to the NSS bypass and check there first.

If you do have voltage at the carb, jump the terminals at the carb switch. If the engine cranks now, that's where your problem is.

If no crank, go to the starter relay and jump terminal #1 to #4. If it cranks now you have a break between the carb and the relay. If still no crank, ground #3 and try again. If it cranks now, you have a break in the lead going from #3 to the voltage regulator.

If still no crank, jump #1 to #2. Use a heavy wire for this one, because it has to carry the solenoid current. If it cranks now, the relay is bad. If still no crank, you have a problem in the solenoid or starter.

Good luck, and please post back with what you find out.

Ray
 
'51 Special said:
The connector lead is actually a tiny cable, made of 7 strands of 9-strand wire, with a (once) flexible rubber insulation covered with cloth, and with appropriate connectors for the stud and points crimped on. By eye, the total uninsulated diameter of the wire is about 14 gauge. I have been unable to find any source for a replacement, and am now looking for similarly flexible wire with which to make up a new lead. I am unsure of just how flexible this lead must be. Obviously, it must be able to tolerate a very large number of small movements generated by the advance mechanism, and not materially affect the speed or extent of the advance. Any ideas?
Click to expand...

I don't have access to a Buick parts catalog, but I did find one for Pontiac online and it shows 1865978 for the wire used 1937-56. Most GM distributors were generally similar in this time period (except Chevy 6), so there is a good chance this would work in a Buick distributor, and it may even be the exact same part.

When I put that number into Google, this came back, so at least you can see if it looks like yours.
http://www.rockauto.com/dbphp/x,car...ic_inch_L6_Distributor_Primary_Lead_Wire.html

Ray
 
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Ray-
The Buick is now running. I'm still unsure of what was causing the short within the distributor, but something I did cured it.
I replaced the points and condenser, and made up a connector lead, using some 27 strand rubber-coated wire I got from an electric motor repair shop. It is still noticeably stiffer than the original, but considerably less stiff than any other wire I could find. (I did find a connector lead in the Bob's Automobilia catalogue, and called out there to learn if it was made of the original wire. Unfortunately, Bob's did not have that information, and I didn't want to make a $25 minimum order just to find out. I will order one from RockAuto.com, as the picture and description look right.) I am curious as to whether anyone has had any timing issues if they used a something other than the original wire as a connector lead.
I don't know if it is related, but after I installed the points/condenser, the engine was significantly out of time, backfiring whenever the throttle was opened quickly. I had so shut down for the night before I got it timed, but will get to that today.
The starting circuit problem was easily resolved, at least temporarily. On the second step of your suggested diagnosis process. ("If you do have voltage at the carb, jump the terminals at the carb switch. If the engine cranks now, that's where your problem is.") The slide on the carb switch was not dropping down onto the operating lever. Apparently it was just stuck from lack of use.
I am going to give the carb a cleaning, and at least some new gaskets.
Thanks so much for all of your help.
'51 Special
 
I'm glad to hear you have both problems fixed, at least for the time being. Don't worry too much about the wrong type of wire affecting the vacuum advance significantly. The vacuum unit can exert quite a bit of force on the breaker plate.

A more important concern is how well the wire will withstand repeated flexing over time. Even the correct wire can be expected to need replacement after a few sets of points. It was never intended to last forever. You may not be aware that the breaker plate has a ground wire which is also subject to the same flexing, so it might be a good idea to check the condition of that one too.

It is entirely normal for the timing to need adjustment after replacing the points. With today's fuel you can usually run more advance than the factory specs. As long as the engine doesn't ping when under load or try to kick back when starting it hot, you should be ok.

Ray
 
Ray-
I had thought of the flexing consideration, as the connector lead wire was frayed near the tab that connected to the points, and broke when I was carrying it around looking for appropriate wire. I had not worried too much about the ground wire (which appears to be made of the same material as the connector lead) as I was looking for a short and its kind of impossible to short a ground wire to ground. The ground wire is not frayed, but has badly deteriorated insulation, and I made certain it would not touch the connector wire. I could easily make up a new ground wire of the same materials I used to make up the replacement connector wire. Would that be wise?
Timing did not go well. The carb is so out of sorts that I could not get the engine to idle under 650-700 RPM, except when it was dying. So that also awaits the overhaul of the carb.
'51 Special
 
Ray-
RockAuto has the connector lead wire, but it seems not to be listed as a part for specific vehicles. However, they do carry it as STANDARD MOTOR PRODUCTS DDL7.
'51 Special
 
Right, DDL7 is an aftermarket supplier's interchange for the GM part no. 1865978 I found online. If you look at the Rockauto page I linked, it interchanges with a bunch of different OE numbers. D1200 was the Delco replacement market number, but I don't believe that part is made by Delco any more. If it is, I couldn't find it with a search.

Delco distributors were also used in non-GM makes like Hudson, Nash, Kaiser, Willys, Studebaker, Packard, etc., so some of those part numbers on the Rockauto page aren't GM. The upper part of Delco distributors didn't change much for different makes of cars. Only the part which went down into the engine was different.

Ray
 
Back again. Timing the ignition has been an issue. Turns out the vacuum advance is not working because the diaphragm in the vacuum control unit is shot. So I start looking for a replacement (Delco-Remy part No. 1116065), and nothing. I look for someone who rebuilds vacuum control units, and nothing. I did, however, find some listings for NOS vacuum control units on EBAY, though none with the correct part number, which appears to fit '49-'52 I-8s (248, 263, and 320), but nothing else. My questions: (1) Does anyone know of a rebuilder; (2) am I being too picky, and could I possibly just look for a unit that fits physically; and (3) Are NOS units likely to be usable, even though perhaps decades old?
 
'51 Special said:
My questions: (1) Does anyone know of a rebuilder; (2) am I being too picky, and could I possibly just look for a unit that fits physically; and (3) Are NOS units likely to be usable, even though perhaps decades old?
Click to expand...
(1) I am not aware of any rebuilder for these things.
(2) Yes, in all likelihood. When I worked in the parts business, most of the replacement advance units we sold were "one size fits all", and no customers ever complained except the ones who didn't need an advance unit in the first place (in other words, they were trying to fix a problem by throwing parts at it in the hope that one of them would stick).
(3) Also yes, in all likelihood. Test to make sure that the plunger moves freely, and of course that it doesn't have a vacuum leak.

Ray
 
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