oilyduke
Newbie
Posts: 6
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« on: February 02, 2009, 01:42:17 PM » |
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What is the normal source of ignition coil failure. I have gone through 3 coils now in 5000 miles and am wondering if I have another problem. Is it something other than engine heat? Could it be fouled spark plugs? I have replaced my ignition wires with new ones, and have cleaned the plugs periodically. Thank you for your help if you have experienced this problem. This is a '65 TR4A.
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jforrester
Newbie
Posts: 7
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« Reply #1 on: February 02, 2009, 05:46:05 PM » |
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In my experience coil failures are almost always due to over heating. Are you sure you are using a true 12 volt coil. Most universal replacement coils are designed to use a ballast resistor which a TR-4 does not have. They will run on 12 volts but not for long. You can add a ballast resistor in series with the either lead going to the coil to make them work. Another good way to cook the coil is to leave the ignition on without starting the engine. Are you sure you are hooking the coil up correctly? With a positive ground car like the TR-4 be sure the positive post on the coil goes to the points lead from the distributor. Another clue of having too much current to the coil is the points will also burn up in a short time. I have never heard of a coil failing due to bad spark plugs. An open spark plug wire can cause failure as it will let the output voltaage rise to a level above the insulation rating of the coil eventually causing it to breakdown.
Hope this is of some help and good luck!
John Forrester
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Mark Richlen
Newbie
Posts: 5
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« Reply #2 on: February 03, 2009, 10:15:51 PM » |
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John is on the right track here. I have never had a coil fail on my TR4 in the 40 years I have owned it. These old coil, points, condenser systems are very reliable. The only coil meltdown that I can remember was in 1966. I was making out with a gal in my 57 Ford, I left the key in the on position instead of accessory so we could listen to the radio. The coil cooked itself, I had to hike into town and "liberate" one from a used car lot. "Liberating" auto parts can get one in trouble; I do not advise it.
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Mark Richlen
Billings, Montana
1963 TR4 Surrey
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oilyduke
Newbie
Posts: 6
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« Reply #3 on: February 10, 2009, 02:14:49 PM » |
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Thank you John Forester and Mark Richlen for replying to my coil failure problem. I think what I may have done is burned up the last one by playing my radio without the engine running. I had the radio on in the car while I was working under the hood, but did not have the car running so that hopefully I can avoid in the future. My car is converted to a negative ground, so I have the positive side of the coil run from the ignition and the negative side to the distributor. Do you think a 2 ohm resistor is enough to put in line, and I am guessing that it would go on the positive side, is that correct? Thank you again for your help.
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Mark Richlen
Newbie
Posts: 5
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« Reply #4 on: February 11, 2009, 10:27:57 AM » |
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Sounds like the coil is wired properly, I run a neg. ground also. I am using a Lucas Sport coil but no resistor. I admit I am not an expert on ignition systems. There is a good article about this on the VTR website. Go to Resources tab on the Home page and click on the Maintenance Manual.
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Mark Richlen
Billings, Montana
1963 TR4 Surrey
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oilyduke
Newbie
Posts: 6
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« Reply #5 on: February 15, 2009, 07:31:15 PM » |
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Mark,
Thank you again. I am Duke Jones and I live in Socorro, NM. I have spent a lot of time in Billings, because I am an oil exploration geologist and have lived in Denver and Casper. My car was probably originally negative ground according to one person I have talked to, and it makes things a lot cheaper with regard to radios etc. as you probably know. I just put in a new radio last year and did not use the accessories function on the switch like I should have while testing and playing the radio. Hopefully this will solve my problems. In the meantime, I tested the original (at least the one on the car when I purchased it) Lucas coil and it tests fine, so I will carry it with me as a spare from now on.
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gusc
Newbie
Posts: 17
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« Reply #6 on: April 27, 2009, 11:43:31 PM » |
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Duke,
I have no idea when As were changed to Neg ground?
If your TR was originally Pos ground and you have the original coil your coil primary side is hooked up in reverse. The way you have it connected now is the original way for a pos ground setup.
However, if it was originally Neg ground it is correct.
You can buy 12v coils with built in ballast resistors at any auto supply store, cheap and simple.
Gus Causbie
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Gus Causbie
'63 TR4, s/n CT10059L
Ash Flat, AR
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gusc
Newbie
Posts: 17
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« Reply #7 on: April 28, 2009, 10:40:45 PM » |
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Whoops, sorry about that!
I'm new on the board and didn't notice how old the post previous to mine was!
At this late date my post certainly won't be of much use!!
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Gus Causbie
'63 TR4, s/n CT10059L
Ash Flat, AR
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Maintenance Issues
