Points Trouble shooting. Need help quick.

MarkM · Mar 6, 2004

I'm trying to get my '66 running. It's an all orinigal 283, with points dist. The guy I bought it from said it has been sitting for 15 years.

It hooked a battery to it, and it cranks just fine. But I'm not getting any spark to the plugs. I don't know much of anything about points distributors, they were gone before I arrived,

. So here what I've done:

The cap, rotor and points look brand new. It surprised me, but I'm not sure if this is a good thing.

I put a new coil on it, it looked original.

The + and - on the coil get juice with the key on. But when I put the test light in the coil output plug, it doesn't show juice when I crank it. Should it?

Where do I go from here?

TDW · Mar 6, 2004

Make sure the neg goes to the dist. Good way to check coil output is to hold the coil wire near a ground. Should jump a spark to the ground when the engine is turned over. Test the 12 volt feed to the coil. Make sure it is hot.

MalibuJerry350 · Mar 6, 2004

Originally posted by MarkM:

The + and - on the coil get juice with the key on. But when I put the test light in the coil output plug, it doesn't show juice when I crank it. Should it?

Where do I go from here?

if you are "getting juice" from BOTH the + AND - connectors on the coil, the points are in the open position. Here's a quick test: With someone cranking the engine, place the test light between the - side of the coil and a good ground (coil bracket, intake, etc.). IF the points are opening and closing, the test lamp will flash on and off each time the points open and close. If the lamp remains lit, the points aren't closing. This COULD be due to the gap or dwell angle being misadjusted, or the contact set being rusted in place. AT ANY RATE (yes I'm shouting) DO NOT TEST THE SECONDARY (the center post)WITH A TEST LAMP! The voltage there will exceed the voltage limitations of the lamp and you WILL get quite a shock!

You can, however, remove the coil wire from the distributor end and hold the connector near (about 1/4 inch) a solid ground. Just be sure to hold the wire a couple of inches away from the connector!

Marcus · Mar 6, 2004

This is a simple circuit.
Ign thru resister wire to + coil out - coil to distributer where the points and condenser are in parallel. You may also have a resister bypass. This is a wire from the R term on the starter to the + coil. When you crank the voltage drops from 14 to 9v. This 5 volt drop does not allow enough voltage to power the coil during cranking so the 1.5 olm resister between the key and coil get bypassed making up for the voltage lost.
+ coil should have either ~6-9v or 12v when not cranking. If the points are closed current will be flowing and you will get an ir drop across the resister wire leaving 9v at +coil. If the points are open no current flows therefore no ir drop and you will get the full 12v.
Tap the engine until the points are closed, connected a sparkplug wire directly to the coil and ground the outside of the plug. Open the points with an insulated opject and you should get a spark and see the voltage rise from 9 to 12.
If hot you have a bad condenser from what I could tell so far. I have also bought a set of unipoints and added wires and clips. Disconnect - coil and wire between ground and - coil. Open and close the points and check for spark as mentioned above-simple.

MarkM · Mar 6, 2004

So my next step should be. Put the test light on the - . Crank the engine. If the light goes on and off, it needs a condenser. If it stays on, the points aren't opening and closing. ?

Marcus · Mar 6, 2004

Measure battery voltage 12.6; measure c+ 9.6; measure c+ while cranking should be near bat crank voltage ~10.4; remove dist cap; connect coil spark tester; open points with non conductor pen or some such and check for spark while measureing + voltage. When you go buy points and condenser get another set of unipoints, 30" wire and 2 gator clips. Connect one to unipoint ground and one to regular wire contact. Disconnect - and connect your new points and condensor in a "can" to the - open and close points with thumb (you will get a slight shock) and check for spark.
Email me and i'll send you a pic of the tester.
You should not have to crank to test other than check positive voltage and rotation. Just open the points like the little cam does.

charbilly2001 · Mar 7, 2004

Remove the condenser entirely. Reassemble everthing. If the engine will start then you know that the condenser is bad. If not you need to do additional trouble shooting.

Do not run the engine for long without a condenser in the primary ignition circuit since that will cause your points to prematurely fail.

MarkM · Mar 7, 2004

Well, I replaced the points and condensor. With the key on, I can move the contact points away from each other, and they spark, but when I crank the engine, they won't spark.

I just want the car to run so I can move it around, I'm not going to be driving the car much at all with this engine in it.

I'm about ready to throw the distributor in the trash can and get a junk yard HEI for temporary use.

.

Bad Rat 414 · Mar 7, 2004

I'm wondering if they are moving at all when you crank it. The lobes could be worn out.

JWagner · Mar 7, 2004

Have you set the gap of the points when they are at full lift? Start with .016 inch and see what happens. Have you looked at the distibutor when the engine is cranking and verified that the points are moving? These points systems were pretty basic and you should be able to get it up and running without a lot of trouble.

MarkM · Mar 7, 2004

Well I did a once over, took it back apart and put in together again. Not sure what I did different, but it fired right up. I think it may have been a loose coil connection or something.

Thanks everyone for the advice, it's really appreciated

. I learned a few things about points too, hopefully I won't need to use that knowledge again,

.

MalibuJerry350 · Mar 8, 2004

Now that it's running, hook a dwell meter up and check the dwell angle. If I remember correctly (got rid of the points distributor a while back!), the reading should be between 28 and 32 degrees.

MarkM · Mar 8, 2004

Thanks. I set them at 30. It's running great now. Hard to believe since it's been sitting so long. The tank was almost empty, so I added some new fuel, and once I got the old ran through the fuel line, it fires right up,

.

I'll post some pics in the bench racing section when I get the car cleaned up, should be later this week,

.

Points Trouble shooting. Need help quick.

MarkM

TDW

MalibuJerry350

Marcus

MarkM

Marcus

charbilly2001

MarkM

Bad Rat 414

JWagner

MarkM

MalibuJerry350

MarkM

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