37DodgeSedan

No spark, condenser?

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My 37 Dodge will not start. I drove to a store and when I came out it would not start. I suspect the condenser since an ohms test shows 1 and does not go toward 0 when connected - are all condensers interchangeable if the wire is the correct length? Does it matter if a condenser is listed for a 12 volt car rather than a 6 volt? I am having trouble locating a condenser that says it fits my 37 Dodge but I think it should be pretty universal.

I also check the points gap, ran a wire directly from the battery to the battery side of the coil, and did an ohms test on the non-condenser wire inside the distributor cap.

If you have other ideas on why it will not get any spark please feel free to post. Thanks...Kurt

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I have quality U.S.A. made Points, Condensers, Rotors & Caps (& Spark Plugs) for the 1935 - 1938 Mopar Application.... All Brand New, of course,

But I don't work on cars -- so can't actually help you on the diagnosis...

 

If you need or want Brand New --- always best to simply call me --

Craig -- 516 - 485 - 1935....

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To test your condenser remove from the distributor . Use a jumper wire and ground the end to the ground battery post. Then scratch the other end of the condenser  to the other battery post a few times. That will charge the condenser . Then try to discharge the condenser by touching the "the other end" to the positive post . There should be a fairly large spark if the condenser is good. If spark is feeble, discard. Use any condenser from a 12 volt system, it will work.  If the condenser is defective the ignition points will quickly burn out. You may mount the condenser any where on the car it makes no difference in operation. There are lots of condensers  mounted outside the distributor cap . Checks for wires inside the distributor plate  for  proper grounding. Yes, the plate must  be grounded to the distributor body .  To test  the coil remove from car. hook up a wire from battery post side of the coil to the battery , plug a high tension wire in the tower. attach a wire at the other terminal of the coil and quickly  spark the other  battery terminal . If the coil is good the spark at the end of the high tension will be hot and blue, with a loud click. You will need a third hand.  

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Most multimeters have a capacitance feature, it should read somewhere between 0.20 to 0.30 (edited) microfarad.

Edited by maok
corrected info (see edit history)

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My multimeter is digital and shows 1 when separate and 0 when the leads are touched together. I had the ohm setting for 20000k which internet searching yielded comments to choose the highest setting. I thought I could energize the condenser from the multimeter by black lead to condenser body and red lead to the detached power lead from the coil. this should have caused a change in ohms over a 15-20 sec interval and then reverse leads to discharge. However, no change occurred at all. I will try the method stated by Trini tomorrow and provide an update.

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3 hours ago, 37DodgeSedan said:

My multimeter is digital and shows 1 when separate and 0 when the leads are touched together. I had the ohm setting for 20000k which internet searching yielded comments to choose the highest setting. I thought I could energize the condenser from the multimeter by black lead to condenser body and red lead to the detached power lead from the coil. this should have caused a change in ohms over a 15-20 sec interval and then reverse leads to discharge. However, no change occurred at all. I will try the method stated by Trini tomorrow and provide an update.

 

Or perhaps just spend a buck or two on a new condenser (20 - 30 uf)  and hook it up as Trini says anywhere on the distributor, so long as it's in the primary circuit to the points.  Saves messing around with the multi meter. 

,

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You can also check the ignition coil attached to the car. Remove the "IN" wire and use a jumper directly from the battery. Remove the "out" from the coil and hook up a jumper wire. Remove the coil high  voltage wire from the cap and keep the tip  about 1/8 to a 1/4  inch from the block and momentarily touch coil secondary wire to  the battery  ON and Off. That way you are mimicking the contact points . If the capacitor is a dud the ignition points will be discoloured with heat marks. I know this  happened to me The fine braided wire from  outside the distributor insulated terminal connected to the points was broken inside the cap, still inside the tiny silk insulator. Tug at it. Ignition coils can get hot  too and inoperable. Keep you contacts open by installing a piece  of  paper  between them and use the good old test light to check for grounds or continuity.

Good luck.

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First I would check the distributor shaft is turning.

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The condenser does not care 6 volt 12 volt.  You can be off on the uf's and it would be ok 50% more or less think of it as a storage unit for current. 

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12 hours ago, hchris said:

Or perhaps just spend a buck or two on a new condenser (20 - 30 uf)

 

No condenser used for points even approaches those values. I don't expect that will work well. I can't remember offhand what is typical, but I could believe the 0.2 - 0.3uf mentioned earlier in this thread.

 

4 hours ago, Mikefit said:

You can be off on the uf's and it would be ok 50% more or less think of it as a storage unit for current. 

 

You CAN be off, and it will run, but if you are the points will burn up right away with contact damage that looks like a mountain. Metal transfers from one point to another. You can tell whether the capacitance (uf) is too high or too low by which point has the mountain on it. Old service manuals like Motor or Chilton have pictures of this. RPM affects it, so driving habits play a part. If a car runs ok, and there is no metal transfer on the old points, I don't change the condenser.

 

a173207.jpg

 

Edited by Bloo (see edit history)

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One more thing, testing with a capacitance (uf) meter will not necessarily tell you if a condenser is bad. Condensers (AKA capacitors) for ignition traditionally used paper for insulation between the foil plates inside. Like the "paper" capacitors in an antique radio, they have to deal with hundreds of volts without insulation breakdown. Failures often don't show up at the low voltages a modern capacitance meter uses for testing.

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New question - is the cam lube just dielectric grease or do I need to buy SL-2 Lubricam, no one local seems to have it though I can get it on-line.

 

The car is now running. I took hchris advice and went to an old former Carquest car parts store that has been around for years and he actually had the condenser that his parts book called for so I asked for points and got them too - wow. The parts seemed difficult for my big hands to install without dropping/losing a screw so I decided to just pull the distributor out and make sure everything was in and set correctly. Cell phone pictures before pulling it out helped make sure it went back in.

 

Thanks everyone for your help!

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Now to really throw a wrench in the works, If one was running pertronix now you have no condenser correct ?   Being no points to burn no condenser?

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I carry a spare condenser in each of my cars, with a 2-ft piece of wire with alligator clips on the ends.  You can attach a spare condenser on the side of the road, bypassing the one in the distributor, without removing the distributor cap.  Just attach the new condenser's pigtail to the coil's low tension post which leads to the distributor, and use the wire to ground the new condenser's case/mounting clamp.

 

Beware of NOS odd-size condensers from the 1920s.  These used waxed paper as the insulating medium, and that will soon break down under heat and vibration if it hasn't done so on the shelf.

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4 minutes ago, Grimy said:

I carry a spare condenser in each of my cars, with a 2-ft piece of wire with alligator clips on the ends.  You can attach a spare condenser on the side of the road, bypassing the one in the distributor, without removing the distributor cap.  Just attach the new condenser's pigtail to the coil's low tension post which leads to the distributor, and use the wire to ground the new condenser's case/mounting clamp.

 

Beware of NOS odd-size condensers from the 1920s.  These used waxed paper as the insulating medium, and that will soon break down under heat and vibration if it hasn't done so on the shelf.

Now that is one heck of an idea I never thought of considering the crap chink condensers we are getting.  I need to remember this for my Franklin. I do keep spare points and condenser but not the wire. (I have been warned if I install pertronix in a Franklin I will be banished to Corsica)  My 46 Dodge did an odd thing to me yesterday where it just shut off.  Coasted to the side of the road where it then started up again fine.  Drove home fine after that. Was thinking condenser.  Might just try this to see if it is the condenser before i swap it out.

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2 hours ago, Brooklyn Beer said:

Now to really throw a wrench in the works, If one was running pertronix now you have no condenser correct ?   Being no points to burn no condenser?

 

It is probably in the module.

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4 hours ago, 37DodgeSedan said:

New question - is the cam lube just dielectric grease or do I need to buy SL-2 Lubricam, no one local seems to have it though I can get it on-line.

 

I doubt distributor cam lube is dielectric grease. Maybe it would be OK. Points should usually come with a little capsule of some grease, but I don't think it is anything special.

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10 hours ago, Bloo said:

 

No condenser used for points even approaches those values. I don't expect that will work well. I can't remember offhand what is typical, but I could believe the 0.2 - 0.3uf mentioned earlier in this thread.

 

 

You CAN be off, and it will run, but if you are the points will burn up right away with contact damage that looks like a mountain. Metal transfers from one point to another. You can tell whether the capacitance (uf) is too high or too low by which point has the mountain on it. Old service manuals like Motor or Chilton have pictures of this. RPM affects it, so driving habits play a part. If a car runs ok, and there is no metal transfer on the old points, I don't change the condenser.

 

a173207.jpg

 

 

Yep you got me there, but my point really was just try another condenser,  save messing with the multi meter. 

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47 minutes ago, hchris said:

 

Yep you got me there, but my point really was just try another condenser,  save messing with the multi meter. 

 

I agree completely.

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