1966 Plymouth Barracuda Help!

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classicRookie66

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Bought the Cuda from my brother as a first car. it Has a 318 v8 in it. I need help or any sort of advice to fix 2 major problems with it. First i was wondering why my ignition coil wont get any spark. it was before and now i recently replaced with a new coil and now i have no spark. i Can provide how i have my coil wiring hooked up if needed.
Secondly when it was running before it had an overheating problem. So i went out and got a new thermostat and had my radiator flushed. Replaced my water pump gasket. Seemed like it wouldn't overheat to bad at idle but as soon as i put it in gear(Automatic) and drive or put any power to the motor it'd overheat ending with the water in my radiator boiling hot. ANY ADVICE OR HELP MUCH APPRECIATED. I've ran out of options and im stumped.
 
Welcome to FABO!

What kind of ignition system do you have on it? Points? Electronic? Aftermarket?

Do you have a service manual for your car?

Go to this site and download a free 66 Plymouth service manual. It's the 'bible' reference to fix your car. You can download any others that interest you while you are there..

http://www.mymopar.com/index.php?pid=109


The wiring diagrams are in the back of chapter 8. Look up the proper ones for your car and use them to help troubleshoot your wiring. Verify you are getting voltage to the ballast resistor with the key in the "run/on" position, then check it at the coil to make sure that you are getting power to the coil.

Our resident electronic expert can help you with that (Del/67Dart273). Put up a post in the electronic section if he doesn't find you here.


As for your overheating problem:

What temp thermostat are you running?

Did you put it in a pot of boiling water to make sure that it opens properly before installing it?

Do you have a good radiator and fan shroud?

Where is your ignition timing set? If not properly set, it may run hot. Small blocks like to run at 34-36° advance at 2000-25000 RPM. Too much advance can make it run hot...

One way to help when it starts to overheat is to run the heater on high to pull more heat out of the cooling system, and also if possible when it gets real hot, run a garden hose through the radiator. Water can take away more heat than air and can help keep it from overheating in emergency. You may not have enough capacity in the radiator to keep the engine cool. Could your radiator need a recore, or is it in good shape?

A good fan shroud will also help pull the air through the radiator. If you don't have one, you may want to find one for your car.

What kind of fan are you running?

Standard or clutch? Mechanical or electric? How many blades?


Maybe take some pictures of the engine compartment from a few different angles and zooms and post them so we can see what you have and be able to give some more advice....

Welcome to the madness....
 
First off, welcome to FABO!! Secondly, congrats on procuring yourself a sweet little car!!

Now, what was the car doing before that you needed to change the coil? It may be that there is something up the line a little that is keeping you from getting spark! Like Karl mentioned, a service manual is a must, and Del will tell you the same! It's easy to follow along with Adele advise if you have at least a wiring schematic. These cars are really easy to trace wiring issues, there's not much to the wiring!

As for the overheating, it sounds to me like a blockage of some sort! As Karl mentioned, a check of the thermostats opening temp will tell you if and when it's opening! A shroud is always a good idea, and a flush of the system never hurts! It could be that the impeller on the water pump is broken and not turning, or the votes in the radiator are plugged! A bottle of Water Wetter could help some, it lowers the friction level of water and can help cool by some 20 degrees or more! Just thinking out loud here, but the fun of owning these cars is sometimes in working on them, and the satisfaction that you can actually "do it yourself",'a craft sadly lost on most new cars!! Be sure to report back on your progress!! Geof
 
there is a difference in having the the rad tanked or rodded out. the tanking may not solve the problem. a GOOD rad shop can easily remove the tank and rod it out, and a good shop will be able to tell you if it needs THAT!
I am assuming you have a correct oem rad you are dealing with?????
 
So i have a Mallory Comp 9000 Distributor running to a 12v Coil that i had just picked up from my local Auto parts Store. The previous Coil was a Mallory and i had tossed it cause the top had a crack in it. I cant remember what temp thermostats in it. I had just put another in because Prior to me putting that in it was ran without one. I had the Radiator taken to a local shop and they said they had cleaned it out and rodded it out. I also just picked up a fan shroud hoping it'd help a little bit. When i replaced the water pump gasket it appeared that the water pump was turning and it is fairly new. I will take pics ASAP
 
Also i Have 11-12v going to the coil but when i read the end of the Coil wire going to the distributor it gives me 4-5v. Also tried getting Spark from using a plug wire but still nothing. I have the wire running from the distributor going to the negative. and the wire coming out of the firewall to the positive. I also ran a wire from the positive to the battery but that didnt seem to help.
 
How many blades are on the fan?? Looks to be a 4 blade unit, of which there are direct replacement 6 and even 7 bladed fans! Start by changing to more blades for increased airflow, and make sure the correct side of the fan is facing out!
 
Looks like the coil wire isnt hooked up to the distributor cap. I think I would invest in some new plug wires also as it looks like the leads are pulled too far out of the boots.
 
blu340dart said:
Looks like the coil wire isnt hooked up to the distributor cap. I think I would invest in some new plug wires also as it looks like the leads are pulled too far out of the boots.
Click to expand...


You can scoot the boots down with some care and maybe a shot of penetrating oil.

I pull them too far back, then install them on the cap, then snug the boot over the terminal...
 
It has a 6 bladed Fan. and i pulled the distributor wire to check for spark. I used volt tester and i get 12v from both the positive and negative on the coil but when i test the end of the coil wire that goes the distributor it gives me 4-5volts. Just curious if i have the right wires leading to my coil?
 
Could that be a reason it wouldn't be getting any spark? I'm sure the boots go down further it was probably from when i was messing with it.
 
Your distributor wire should go to the negative post of the coil. As for the overheating issue I would suspect that you have a blown head gasket since you have pretty much done everythin else to prevent overheating. Have you checked the oil after running hot? Is there water in the oil? One other thing to check would be the heat riser on the exhaust manifold. With the motor warmed up check the radiator hoses and make sure they are not colapsing on you, if they are soft and overly pliable put new ones on. Run the car and turn on the heater to warm air you may have an air blockage, while doing this run with out the radiator cap. Good Luck
 
I don't think its a blown head gasket. The exhaust fumes are pretty clear when she gets warmed up. Ive checked the oil and water when running and they look to be alright. It sat for awhile before.. could there be something in the block thats clogging water flow?
 
When i was messing around with wiring. The tempature raised to hot before the car was even started... could it be possible theres a heat sensor that makes the motor think its running to hot? it has went all the way high before and killed itself.
 
If the voltage limiter on the factory gauges is starting to go, sometimes you will get a surge and the gauges will read a few notches high, then it will go back down when the surge ends....

Could this be happening to you?
 
I had a 360 with 308 heads and one head developed a crack near the exhaust valve seat. Must be a water jacket there cause it would eventually over heat but no water would leak. I'm thinking exhaust gas got in through the crack heated the water and over pressurized it.
 
First off, it looks like you are trying to use socket type plug wires on a HEI style cap. This won't work well if at all. What is the voltage at the coil?

As for the overheating, it also appears to have a "flex fan". These are notorious for maximum noise with minimum cooling. But so long as you are going over 35 MPH or so, the fan really doesn't matter.

Get it running and set the timing to something reasonable (10-12 BTDC) and then troubleshoot the cooling system.
 
ill have to take a look at my heads and see if they're cracked. The Positive and Negative both read 11-12v on the coil but read 5-6v at the end of the Coil wire that plugs into the distributor. Ill try messing with the timing. As for the Gauges a lot of them don't work. The temp "does" and the spedo works but nothing else. When the temp goes hot it stays hot until i release the pressure at the radiator and let it cool down.
 
Alot of work done to the motor was done at an autoshop. but that was in 2007. plug wires was a thing replaced. could they be wrong on the plug wires?
 
You shouldn't have to pull the heads just do as mentioned above, have a radiator shop test coolant for combustion gasses.
 
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