How do I test a distributor?

[bmwillia]

Hey guys,

How can I tell if my distributor is good? Is there a way to test it?

I took one of the plug wires off of the plug and held it close to the plug looking for the spark and didn't see anything. I should shouldn't I?

Is that the best way to test?

Thanks!

[George/Maine]

Hookup like in car set on fender or work bench.
Take wire out of cap and 1/2inch from grd.,power to coil,longer wire to dist.
Set your points and condenser.Turn on power and turn by hand and see if sparks nice snapping sound 1/2 to grd.Now oil and make sure shaft not worn.
If all ok put on engine and should start.

[ford38v8]

Well, if he keeps your beer kegs full without a shakedown and doesn't knock up your Barkeep, I'd let sleeping dogs lie.

[Henry/Kokomo]

Boo-o-o-o-o-o

[Old Henry]

Originally Posted by bmwillia

Hey guys,

How can I tell if my distributor is good? Is there a way to test it?

I took one of the plug wires off of the plug and held it close to the plug looking for the spark and didn't see anything. I should shouldn't I?

Is that the best way to test?

Thanks!

Three things create the spark: coil, condenser, and distributor points, so you need to test each seperately.

COIL
Assuming that you have a coil separate from the distributor, test it first this way:
1. Disconnect wire from distributor side of coil and connect jumper wire to that coil terminal.
2. Unplug high tension wire from coil that goes to distributor and insert a short spark plug wire.
3. Turn the ignition on and check with test light or volt meter at the battery side of the coil to make sure you have proper voltage there.
4. Hold the end of the sparkplug wire near a head bolt while tapping the end of the jumper wire from the distributor side of the coil on a head bolt. That tapping of that jumper wire will duplicate the action of the points in the distributor in turning the coil on and off quickly. Should see a nice strong spark at the end of the spark plug wire coming out of the coil. If so, the coil is good. If not, the coil may be bad. One other test of the coil is to test the resistance of the primary and secondary circuits in the coil. Here's an illustration showing what they should be:



CONDENSER
The condenser can be checked with a multi-meter by either checking the microfarad reading (the better way) which should be at least 24 mfd (most of the stock style made in Argentina), better over 34 (Echlin from NAPA), or, if you don't have a multimeter that tests microfarads you can get a pretty good idea if the condenser is working by using the ohms function of the meter. Connecting the two probes of the meter to the condenser wire and case should show ohms climbing rapidly from 0 to infinity. If you get a good reading on either of those tests the consender is OK.

DISTRIBUTOR
Then test the distributor separately to make sure the points are opening and closing by running a test light from the ungrounded side of the battery to the end of the wire you disconnected from the coil. Leave the key off and crank the engine. Should see the test light go on and off. If so, you know the points are working. If not, the points are bad and need replaced.

Most likely you'll find one of those three components failing and know which to work on or replace.

OTHER
If the coil, condenser, and distributor points check out but you're still not getting spark to the end of the sparkplug wire, the next culprit would be the high tension wire from the coil to the distributor, the rotor in the distributor, the distributor cap, or the spark plug wires themselves. Rotor and distibutor caps are pretty easy cheap fixes to just replace them. In my experience they are rarely the problem. Lastly, the spark plug wires. One easy test of those is to run your engine in a totally dark garage and see if you can see any sparks jumping from the wires to nearby metal. If so, they need replaced as you're losing spark before it gets to the plugs.

This may be a little overkill answer to your question but stuff you might need to know if you don't.

Good luck.

[bmwillia]

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Thanks for the info Henry!

Thank you all for bearing with me... I am just learning most of this stuff.

[Old Henry]

Originally Posted by bmwillia

Thanks for the info Henry!

Thank you all for bearing with me... I am just learning most of this stuff.

You're welcome. No problem.

We are all "just learning most of this stuff."

Good luck.

[bige386]

Brad ... On my 46 I lost all the juice through the distributor. No Spark to any of the plugs. It ended up being the little threaded stud that the condenser bolts up to lost connection on the inside of the distributor. Remove the condenser and then remove the stud that the condenser bolts to. I used a set of needle nose pliers to remove it. Once you get that out clean the end of it and and give it a shot of WD40 the little pin at the bottom is spring loaded and should move in and out. Once you get all of this done put everything back together and try to start your car. Hopefully it will start for ya.

[Bassman/NZ]

We are all "just learning most of this stuff."

Heh heh... aint that the truth!

[bmwillia]

Thanks guys!

I'll check the condenser.

I have another couple of questions....

Is the coil built in to the top of the dist. on the 33? I have the shop manual and that seems to be what it is saying unless I am reading it wrong. I don't have a separate coil like the one Henry showed in his illustration.


Also, I have removed the old wiring harness as it was old and brittle and getting in the way. Are any of those connections needed to provide power to the coil? I currently only have the battery connected to the starter through a solenoid. There are no other wired connections(other than spark plug wires).

Thanks again guys!

[Jay in Mass]

Originally Posted by Old Henry

Three things create the spark: coil, condenser, and distributor points, so you need to test each seperately.

COIL
Assuming that you have a coil separate from the distributor, test it first this way:
1. Disconnect wire from distributor side of coil and connect jumper wire to that coil terminal.
2. Unplug high tension wire from coil that goes to distributor and insert a short spark plug wire.
3. Turn the ignition on and check with test light or volt meter at the battery side of the coil to make sure you have proper voltage there.
4. Hold the end of the sparkplug wire near a head bolt while tapping the end of the jumper wire from the distributor side of the coil on a head bolt. That tapping of that jumper wire will duplicate the action of the points in the distributor in turning the coil on and off quickly. Should see a nice strong spark at the end of the spark plug wire coming out of the coil. If so, the coil is good. If not, the coil may be bad. One other test of the coil is to test the resistance of the primary and secondary circuits in the coil. Here's an illustration showing what they should be:



CONDENSER
The condenser can be checked with a multi-meter by either checking the microfarad reading (the better way) which should be at least 24 mfd (most of the stock style made in Argentina), better over 34 (Echlin from NAPA), or, if you don't have a multimeter that tests microfarads you can get a pretty good idea if the condenser is working by using the ohms function of the meter. Connecting the two probes of the meter to the condenser wire and case should show ohms climbing rapidly from 0 to infinity. If you get a good reading on either of those tests the consender is OK.

DISTRIBUTOR
Then test the distributor separately to make sure the points are opening and closing by running a test light from the ungrounded side of the battery to the end of the wire you disconnected from the coil. Leave the key off and crank the engine. Should see the test light go on and off. If so, you know the points are working. If not, the points are bad and need replaced.

Most likely you'll find one of those three components failing and know which to work on or replace.

OTHER
If the coil, condenser, and distributor points check out but you're still not getting spark to the end of the sparkplug wire, the next culprit would be the high tension wire from the coil to the distributor, the rotor in the distributor, the distributor cap, or the spark plug wires themselves. Rotor and distibutor caps are pretty easy cheap fixes to just replace them. In my experience they are rarely the problem. Lastly, the spark plug wires. One easy test of those is to run your engine in a totally dark garage and see if you can see any sparks jumping from the wires to nearby metal. If so, they need replaced as you're losing spark before it gets to the plugs.

This may be a little overkill answer to your question but stuff you might need to know if you don't.

Good luck.

WOW!!! Prof.Henry.... That was great. I'll have to put it into my "Favotites Folder" Jay in Mass

[G.M.]

Brad the way for you to test the SPARK required to run your engine is. Fully charge the battery before you start, read the battery voltage it should be in the 6.3, 6.4 range. Put a volt meter from the power wire on the coil to a good ground. Turn the ignition switch on and read the voltage. When the points are open it should be close to the battery voltage. bump the starter until the coil voltage drops, this indicates the points are closed. You should have about 4.0 with the points closed. If it is below 3 volts the engine will be hard to start or may not start at all. Some times with boarder line low voltage it will start just as you leave off the starter button or may start with the car being pushed. If the voltage is low with a fully charged battery it indicates a bad battery connection, ground, a wire from the battery to the coil, dirty ignition switch or resistor. You can put a jumper from the NEG on the battery to the coil and get full battery voltage to start it but don't let it sit with this jumper or run for long periods of time. This proves the area of the problem is in the wire,switch, or resistor from battery to the coil. To test the quality of the spark remove one plug wire and jump spark from the wire end to a head nut or base of the plug NOT the terminal on top of the plug. You should get a crisp blue spark that jumps about 1/2". A weak yellow spark indicates low voltage to the coil, bad coil, condenser or points. 99 % of all stock Ford coils used or NOS will have a weak spark the hotter the coil gets. They will all start cold but check the spark when they get good and hot. This makes it hard to start or won't start at all for 20 minutes or more until it cools down. The only REAL way to test and set a Ford front mounted distributor is on a distributor test machine. This sets the timeing and dwell to the original factory settings. The vacumm piston is also tested and set on the machine. Skip does the distrbutor testing and sets them up on the original Ford~Heyer Strobe machine the authorized Ford rebuilders were required to use. Properly set up these distributors run trouble free for years. G.M.

[Henry/Kokomo]

Brad - To answer your specific questions, 1) Yes, the coil is on top of the distributor. 2) You mention removing the wiring harness. It isn't necessary as long as you have a wire from the Neg. battery terminal to the ignition resistor and a wire from the resistor to the coil. I'm not familiar with 33's so I can't tell you where the resistor is located (on firewall or under dash? ). Those wires are necessary for the engine to run. The ignition switch should be between the battery and the resistor. Hope this helps.

[bmwillia]

Thanks Henry!

That may be why I am not getting a spark. At first I thought maybe it used a magneto and didn't need power from the battery. Then when I read in the manual that the coil was in the top of the dist. I figured I needed some wiring.

Good info! Thanks again!

[Henry/Kokomo]

Glad to help. If there is no battery voltage to the coil, there will be no spark - guaranteed. No magneto action of any sort in the stock ignition.

[Mike in AZ]

Brad....ask the questions....i love some of the answers which cover everything...and i'm always learning something new...or just new info to add to my old info.....here are links to MacVP's website, if you haven't been there already, showing the electrical wiring...lots of good info there..good luck and have fun..Mike

http://www.vanpeltsales.com/FH_web/F...1933-34car.jpg

http://www.vanpeltsales.com/FH_web/F...wiring1934.jpg

[bmwillia]

Awesome Mike!

Thanks!

[Mike in AZ]

lots of good stuff on that website....got it in my "favorites"...not just electrical ....have fun....Mike

[bmwillia]

Ok..

I have a very simple set up right now.

Neg battery cable to solenoid. Other side of solenoid to starter. I have a wire connected to the starter side of the solenoid to the resistor then from the resistor to the dist.

When the mechanics button is pushed I am getting 4-6v at the dist., but I have only seen a faint yellow spark from the plug wire to the head cover stud.

Should I have the wire on the battery side of the solenoid?

Shouldn't I see a stronger spark from the plug wire?

Thanks guys!

[Old Henry]

Originally Posted by bmwillia

Should I have the wire on the battery side of the solenoid?
Thanks guys!

Yes. Or, better still, right to the battery clamp/post. Otherwise you will only have current to the coil as long as the starter button is pushed.