Technical horizontal mounted coil

Ok over on another forum Ive got in a discussion about coil mounting. the other guy claims a horizontally mounted oil filled coil will overheat. My contention is lots of engines like FE fords came from the factory with horizontally mounted oil filled coils. And they never failed because of how they where mounted. I think the coil don't know or care how its mounted?

 

Seems to me Ford has been known to mount them that way for years without any problems. HRP

 

On a Horizontal mounting of the coil, If you mount it so the terminals are horizontal they are fine. If you mount it so the terminals are vertical they will then overheat as the upper terminal, inside, won't be fully immersed in oil.

Hope that makes sense.

 

There are other forums???

 

The Chrysler 300 engines had a very special bracket welded to the left side valve cover as there was no room for the coil due to the 2x4 intake. 300 engine valve covers are specific due to that fact. There is a left and a right.
Other Chryslers had covers that would be lefties righties whatever. How the coils mounted on those "common" type engines I an not sure. I do know that the 300 hemi had the coil mounted horizontally.
Would Ma Mopar mount a coil on a special engine like that one in my garage improperly?

 

If you rotate yours so the terminals are horizontal instead of Vertical it will run cooler and last longer. As someone who works for a coil manufacturer, I can tell you it's just a good practice. The way it is now, depending on how full they got it with oil, the upper bobbin could be partially out of the oil, creating heat. A no cost change that is like cheap insurance.

 

So what's the scoop on vertical mounting?...is there any potential problem thereDon?..and on the coil subject why are some common size round coils marked " electronic ign. Only"? Do they have a higher amperage draw and toast points quicker?

 

- yep, even if came from factory otherwise

 

My thinking is that the coil is not completely full on purpose. That makes room for expansion. When warm the oil expands and will almost 100% fill the coil. so the mounting position don't really matter. I once left the ignition switch on . It was on a tractor. And the coil did overheat and explode. Apparently the oil expanded beyond 100% of capacity?It blew oily wax all over the side of a vehicle parked next to it. A question is the oil in the coils the bad type of transformer oil like they put on the streets at Dioxion City? Ive taken apart coils and poured the oil in my trucks gas tank.

 

If the upper bobbin is partially out of the oil, with the coil in the horizontal position, that says that the coil isn't 100% full. So, if the same coil is then turned to the vertical position, wouldn't both bobbins be almost out of the oil ?

 

I agree with your assessment. Until the coil warmed up and the oil expanded both connections likely would be above the oil level.

 

old chevys have the coil mounted upside down. I've never seen them leak.

 

When we first got my Son Dans rpu running we had an issue where he could go a few miles and it would start to cut out. We kept blaming it on fuel issues. If it sat for a little while it would fire up and go a few more miles without issues, but then quit again.

One day, when he was having the problem, we touched the coil (mounted horizontally) and it was red hot. I ran to the shop and got a fresh coil and he got home. Then we remounted the coil vertically, and it has never had the same problem, and the coil stays moderately cool.

Since that time we have mounted every coil on every build vertically and have had no more overheated coils at all.

Don

 

That is a great looking engine !

 

And its just possible that the original horizontally mounted coil simply was defective? Now if you had mounted the fresh coil horizontally and had the same problems. Or Did you remount the original coil in a vertical position and the trouble went away? Was it the exact same coil that became trouble free after you changed the mounting position. and did you add a resistor? or install a coil with a internal resistor? Then there would be some merit to your assessment? Your story just isn't logical too my experience I could be wrong? The horizontal mounted coil on my 66 ford F 600 never failed in 160,000 miles if driving. My dad had a 66 ford car he bought new. 428 FE horizontally mounted coil. We ran that engine 325,000 miles never a bit of coil problems. I still have the engine and that same original coil is still mounted on it. there are some coils that have a internal resistor. And most coils require a external resistor or a resistance wire. Those with the resistor usually have a boost of full current when the starter is spinning.

 

There was guy named Verlin. He drove 235 six cyl chevy pickups. And he always mounted the coils pointing straight down. He claimed that helped to keep them from drownding out when they got wet? Every time he painted his house. He bought a few extra gallons and with a brush painted his trucks with the house paint! He was the first guy I seen with the frantz toilet paper oil cleaners on his vehicles. I dismissed them as just something nutty folks used. I bought one at auction and just because tried it. And It actually does what the manufacturer claims?

 

I do remember the partsbook having different coils for applications and mounting differences and notes in there saying not for horizontal mounting , but we als0 had ones that could mount any position and most it seemed were Fords/mopars , they were not universal unless you bought the epoxy filled units or a E style coil . also some cheaper coils would be short filled , one company I remember in particular sold some 1/2 price coils that were aluminum wired and short filled and them suckers would come back occasionally bloated or the cap blown off , specially if they forgot the resistor we used to call them shorys as they would melt the windings and short out .

OLd wolf PCBS were discontinued in the mid 1970's so the waxy stuff more than likely was PCB , in liquid form its safe as long as you do not burn it ( most dangerous way of injesting it ) or eat it . also the stuff (PCB) doesn't expand like newer transformer oils which is a napatha based dewaxed oil , when we hauled this stuff ( transformer oil ) we heated it in transit and it would expand 15% BY volume , so we would load up 5000 gallons and by the time we delivered it was close to 6000 gallons

 

Chevy did mount their 6 cylinder coils upside down, perhaps to keep water away from coil wire to coil connection.
BUT, the problem with the upside down coil was also discovered by Chevrolet.
The coil wire had a tendency to wiggle its way out of the coil, when left the customer with a "no run" condition.

 

So there are rare instances when certain coils if mounted in other than a vertical position that's they would possibly fail? I suppose im lucky in that in over 50 years and as much stuff as I have experience with Ive never run across one? I have run across a bad condenser a few times. There was a town just west of St Louis. Times Beach I think. They poured transformer oil on the streets to keep dust down. And They claimed Dioxin was causing cancer. The government bought the houses. dug up the streets and put the material in sealed containment. I think you can see part of it from I44.

 

Funny old things, them coils.
Mounted up wrong, it boils.
And if you're so calloused
to forfeit the ballast
The bastard will puke out its oils.

 

Don,
Do you mount them on the bottom or the top. Does it make any difference?

@Old wolf actually some GMs came with them mounted horizontally as well.

 

I have been mounting the Delco GM 12 volt coils that where originally mounted vertical in a horizontal position on my tractors for at least 5 decades. The first picture I posted is a 12 volt Delco Coil that has been on that 1944 M farmall for at least 50 years. I have a wire I attach to bypass the resistor when starting it. I have numerious times forgot to unhook it and then remembered and the coil was hot to the touch.. But it still works ok . I havealso mounted a Delco coil sticking out from the firewall on my 55 chevy. buzz it to six grand and it never gives problems.

 

It has more to do with the internal design of the coil. Most modern electronic ignitions have 'dwell control' which means that the coil is 'turned on' for a specific amount of time for each firing, regardless of RPM. This is done electronically in the control circuit. Point ignitions don't do this; dwell time increases as RPM drops (the points stay closed longer). These type coils are optimized for a relatively short 'on time' (like at max RPM if using points) and without the dwell control will overheat and burn out at slower speeds.

 

I have owned more then one old chevy truck with the coil mounted sideways on the intake. Never had a problem and changed the coil to after market on a few.

 

Horizontal or vertical, I don't know. Old Wolf has a lot of anecdotal evidence that it makes no difference, other people have had other experiences, but no one can say for sure that any failure was due to the coil being mounted horizontal. In any case, when mounted horizontal, I don't see that it matters which position the terminals are in. Inside the coil is an iron core in the center, around that is a secondary coil and around that is a primary coil. The primary coil is connected to the terminals, it is a round coil of wire going around the inside of the coil housing, only the wires connecting it to the 2 terminals are exposed out of the oil. And the main purpose of the oil is insulation, any cooling is a secondary benefit and it only cools by transferring heat from the coils to the walls of the coil where it dissipates to the atmosphere. I'd say there's not usually a lot of heat generated in a properly operating coil.

 

There is paper between the primary and secondary coils that insulate them from each other. Even when mounted horizontal the oil level should be sufficient to be wicked up by the insulating paper and provide the insulation needed. On some coils, maybe the oil level is low, or it leaks out when horizontal, leading to a loss of insulation and then a short circuit. If the short occurs between the primary and secondary coils that's the end of that Jack.

 

I suspect that some coils are simply made to run on their sides and some are not. To answer Old Wolfs question, yes, we did try a new coil on it's side and it too got really hot. At that point, all we knew was that the coil was getting hot and we suspected that was because it was mounted directly to the side of the motor and sucking up heat.

I called Accel and talked to the tech there, and he said he really did not care for their chrome coils, he much preferred that ugly big yellow boxy one, but there was no way we were going to use one of those on a hoodless car. The chrome one that has been on there for 5 or 6 years is still going strong, since mounting it vertically. I have been running a chrome one on my 27 for over 25 years (not the same one, I did change it out when the chrome got funky) and it is mounted vertically too. (The tech at Accel said to mount the chrome one vertically too)

So, maybe my original thought is correct, some coils are ok on their sides and some need to go vertically. Personally, I am not taking any chances and, although I have had cars from the factory with horizontal ones, my chrome coils will go vertically.

Don

 

Figured I'd add on to an existing thread rather than starting a new one.
I'm curious, would coil mounting position matter on a coil with an internal resistor?

 

My dad had a 65 Chevelle with a factory 327 350hp in it , the factory coil mounting bracket laid the coil horizontal . He sold the car in the 70's ,kept the aluminum intake and coil bracket and still runs them on his 55 chevy to this day , never had a problem