Thread: distributor/ coil questions

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I have an old car (57 chey)that I am trying to revieve from the grave (sitting about 10 years). I know just enough about cars and motors to be dangerous. But what better way to learn then to do some hands on work.

With that said, I got the car to turn but it wont start. I pulled the spark plug wire and there is no spark. the distributor is one that has points. I noticed that there is a capistor like thing on the side of the coil that is not connected. Where does that wire connect?

I assume that is my problem. Thanks in advance for any help.

sanpedro

Does it look like the attached photo? If it is, it's a ballast resistor. The wire coming into it is from the ignition. The output connects to the + (or BAT) side of the coil. It would definitely keep your car from starting.

However, if you haven't started this car in 10 years, there are other things you should do - like change the oil, get rid of as much of the old gas as possible, put in new gas, change the fuel filter, shoot a small amount of WD-40 in the spark plug holes, check to see if there is any junk (like mice) in the carb throat that can be sucked into the engine.

Also, read this thread:

http://www.clubhotrod.com/forums/sho...+an+old+engine

no it does not look like the photo. It is attached to the side of the coil and it is round and cylinder shaped.

I have a wire coming in from the dash to the positve connection on the coil and then the neg connection goes to the distributor.

I have disconnected the fuel line and I am just pouring aliitle gas in the carb. I did change the oil, but I did not spary wd40 in the spark plugs.

any other advice would be great. thanks for the response.

so why do ya'll think I am not getting any spark? bad coil? how can I check that?

sanpedro

You need a capacitor (or condenser) in the circuit across the points to form a resonant circuit against the inductance of the coil primary. Sort of how a shock absorber works against the cars springs.

Usually it's mounted on the points plate under the rotor but sometimes was moved to the outside of the distributor on dual point units.

The car may start without the capacitor, but will chew points up at a ferocious rate. Without the capacitor when the points open a good portion of the stored energy in the coil will try to jump the point gap, lessening the energy left for the plugs.

That said grab a multi-meter that has at least an OHMs and VOLTs range. With the ignition off measure the ballast resistor - it should read 0.5 - 1.2 Ohms. This sets your running current to the coil primary.

Check the points visually, do they open and close? With the wire lifted between the coil and the distributor measure the resistance between the post on the distributor and the block. Open and close the points with a screwdriver tip or by rotating the distributor housing. The readings should alternate between zero and infinity (a bunch).

Connect the wires back up. Change to the volts range on the meter (be sure otherwise you'll let the magic smoke out of the meter). Turn the ignition switch to the RUN position. You should be able to measure +12V or so at one end of the ballast resistor, and maybe +3V at the other when the points are closed. Open the points and the voltages should both be +12V.

There should be a wire that bypasses the ballast resistor during starting. This allows more current to flow into the coil primary when starting, a time when the battery voltage drops down to +7V or so. If this is suspect then you can add a small wire across the ballast resistor, just don't leave the ignition switch on for very long in this condition or you'll kill the ignition coil.

Pull the high tension wire off the distributor (center) which comes from the coil. Slip a single plug into the wire end and lay it against the block. Have someone crank the engine while you watch for spark.

If you have spark then move to the distributor cap, rotor, plugs, and plug wires. All have been replaced I assume?

Has the distributor been pulled since it last ran, was it re-installed correctly?

Regards, Mark

thanks guys for the info. let me do some testing and I will gett back with more info/questions

thanks for your help

sanpedro

looks like I am not getting any power to the coil? SOme fuses are missing, I am trynig to find out what size (amp) fuses go in the box. Also, it looks like the wires are disconnected on the steering column that keep the car from stating while it is in gear(auto) Am i headed in the right direction?

sanpedro

Run a jumper wire from the positive battery terminal to the + side of the coil---pull a plug, lay it on the manifold so its grounded, (with plug wire attached) crank motor over---you should have spark unless you have bad points or coil. ---make sure the car is in park or neutral.---if car starts, ya gotta yank that wire to shut it off----don't walk away and leave that wire hooked up---thats same as leaving key on, and could start a fire.

That 57 is a nice score,,,,and if i were you i'd go down to my local parts store and pic up a new 'Points set' Cap and Rotor,,,,they are the most basic of all the chevy parts,,,easy to find,,,,maybee swap out the Coil from another engine you know to be working.
Get yourself a Chiltons or Haynes book from the library and do the job right the first time.
And the wire under the steering column could be the neutral safety switch like you say,,if it's automatic transmision.
Like the other guy's said,,,Make damn sure you got that car in neutral or park,,,and maybee put some wheel blocks in front and behind the tires,,,,you dont want it jumping into gear unexpectedly.

Originally posted by sanpedro
looks like I am not getting any power to the coil? SOme fuses are missing, I am trynig to find out what size (amp) fuses go in the box. Also, it looks like the wires are disconnected on the steering column that keep the car from stating while it is in gear(auto) Am i headed in the right direction?

sanpedro

That 57 is a nice score,,,,and if i were you i'd go down to my local parts store and pic up a new 'Points set' Cap and Rotor,,,,they are the most basic of all the chevy parts,,,easy to find,,,,maybee swap out the Coil from another engine you know to be working.
Get yourself a Chiltons or Haynes book from the library and do the job right the first time.
The problem with the fuses wont have anything to do with starting the car.
And the wire under the steering column could be the neutral safety switch like you say,,if it's automatic transmision.
Like the other guy's said,,,Make damn sure you got that car in neutral or park,,,and maybee put some wheel blocks in front and behind the tires,,,,you dont want it jumping into gear unexpectedly.

Originally posted by sanpedro
looks like I am not getting any power to the coil? SOme fuses are missing, I am trynig to find out what size (amp) fuses go in the box. Also, it looks like the wires are disconnected on the steering column that keep the car from stating while it is in gear(auto) Am i headed in the right direction?

sanpedro

Sanpedro, did you find if the IGN fuse was one of the missing fuses? I'd have to guess it would require a 15-25 Amp rating if not marked on the fuseholder.

Mark, heres the way I remember it. If the condensor was mounted on the coil, it was for radio noise. Being mounted on the coil to the + side cannot work with the points, because the condensor has to interfere with the ground side of the points itself. Or, the voltage would just pass through the points to ground. (actually, because the points move, they would want to weld together). The single point distributors had the condensor inside the distributor. The ones mounted on the outside of the Distributor, was for dual points, and were almost double that of a single set of points, because it worked with 2 sets of points. And, the first thing he should do, is see if there is any juice even going to the + side of the coil

Denny, If the capacitor was mounted on the coil (+) it would be there to take care of interference (EMI/RFI) from the generator brushes or the coil as you suggest. It can be placed on the coil (-) which would be the same as if across the points on or inside the distributor. Sanpedro didn't mention where it was located so I made the assumption it would be between the coil (-) and ground.

The capacitor (or condensor, depending on our age) serves several purposes. One is to quench the arc that forms across the point(s) when they open. This increases point life by reducing pitting. The second function is to limit the rate of rise (dv/dt) in the coil secondary voltage and develop what is refered to as a ringwave. This particular waveshape is better at generating an ignition spark. The capacitor value is tuned against the inductance of the coil just like the tuning circuits in older radio's.

As has been suggested earlier, the best bet is to go down to your local Autozone or Kragen and replace the points, cap, rotor, condensor, plugs and plug wires. Blow the better part of $50.00 and eliminate as many future problems as possible. Things that have to handle 20,000V need to be kept clean and dry.

The first item though is to get +12V onto the coil (+) terminal when cranking, and a missing fuse sounds like the best place to start.

Regards, Mark

I have not been able to tell what fuses are for what yet. I am trying to locate a good guide on my 57 so I can figure things out on it. Also , any good newbie guide on small block chevys? any suggestions would be apprecaited. Maybe with those guides I wont bother you guys with so many questions.


thanks

sanpedro

You might try Danchuk Industries, they're one of the largest suppliers of 55-57 Chevy parts. Here's the link to their documents section.

http://www.danchuk.com/manuals.html

Regards, Mark

thanks I will try there!