How hot is a coil supposed to get?

[Bee1971]

"Wouldn't ET slips of the results of testing different coils under the same conditions that show results, be more worthwhile?
BOB RENTON"

Let us know when your done , and your results

Thanx Scott

 

[4406bbl]

So here is some info on what I’m running

Mopar ECU P4120505
No name Electronic Distb

And have these 2 coils

MSD High Vibration Coil 0.7ohms
Calls for a 0.8 BR when using points ignition

Petronius Flame Thrower 1.5ohms coil calls for no BR.

With that ECU, what combo of coil and BR should

Been messing around with coils in my car, got a MSD high vibration (can be mounted horizontal) and this thing gets smoking hot after 5 min of idling. Engine starts spurting and then does. The. Takes a quite a few cranks to fire back up. Is this normal? I did jump the ballast resistor.

67 cornet
440/727
Mopar orange box with no name electronic distb
Just required the engine and upgraded the volt reg and alternator too.

View attachment 1336841

As others have said unstrap the ballast, measure the ballast as you want .5 ohm not .25 ohm. That coil and the accel coils wants a .7-.8 ohm ballast but I have run them with
.5 ohm for years no issues. If you go too high like 1.5 they like to miss at high rpm, weaker spark.

 

[ka0mek]

Been messing around with coils in my car, got a MSD high vibration (can be mounted horizontal) and this thing gets smoking hot after 5 min of idling. Engine starts spurting and then does. The. Takes a quite a few cranks to fire back up. Is this normal? I did jump the ballast resistor.

67 cornet
440/727
Mopar orange box with no name electronic distb
Just required the engine and upgraded the volt reg and alternator too.

View attachment 1336841

mount the coil to te fenderwell

 

[4406bbl]

Dug out some original and NOS mopar brand dual ballast resistors, the original 71-74 3656199 ballast with the part number moulded in measures
1/2 ohm on the coil ballast and 5 on the the compensating side, new or used measure the same. The 75-78 ballast 3874767 measures 1.2 ohms on the coil ballast, and 5 ohm on the compensating side, new or old. It also appears the later resistor superceded the old one for the early cars. I can say for sure that I have used a stock mopar box, with the 3874767, and the accel chrome coil for decades and over 100,000 miles on my 4x4 with no failures, not even the ballast. I cannot guarantee that it would rev past 5500 but there is no need on this. In the 70s and 80s, with the chrome box we would use a 1/4 ohm ballast at the track, then add another 1/4 ohm in series to drive around with, this chrome coil is that old. It will go out now for sure. I need to dig out some service manuals and see if the coil resistance changed in the later years, or if they were trying to keep the control units from burning up. Anyway with ballasts you had better measure them to be sure.

 

[RJRENTON]

Can you read ?

Explains plenty of what if

On the dyno

"It is an E-core design. I did try an MSD E-core with the MP boxes and about 4500 rpm it started popping and missing.
I am not quite done testing coils and boxes,but someday soon I will have to move on to other things."

Same thing I experienced if you read my posts

OTHERS MAY VARY

I can read extremely well and interpret what I read.....in a factful way.....perhaps the demonstration is meant to sell MSD equipment. Do you know the significance of an "E" core coil?......and it just not the shape of the laminations.....
BOB RENTON
....

 

[67 Coronet Conv]

update, unplugged the jumper on the BR and took it out for a quick 5 min drive. Came home and pulled in the garage to check and top off the tranny fluid while the car was idiling in N then it dies and won’t fire back up.

Took some readings with the key on
Battery-12.26v
BR is at 11.26 & 6.8
Coil is at +6.75 -2.14
Check my ign switch and was getting 12.25 there.
BR is at 0.8ohm

Swapped the coil, nothing. swapped the ECU, nothing.

Any ideas why it won’t fire up? When it sits for like 5min it will fire up for 1 sec then die and won’t fire again. Car is getting fuel and spark. Checked it with a inline spark plug tester.

 

[Geoff 2]

It might be flooding; leaving it sit for awhile allows the excess fuel to evaporate, but could still be hard to start. Do you have another carb you could try?

 

[67 Coronet Conv]

It might be flooding; leaving it sit for awhile allows the excess fuel to evaporate, but could still be hard to start. Do you have another carb you could try?

Only have the carb that’s on it.

 

[Ranger16]

update, unplugged the jumper on the BR and took it out for a quick 5 min drive. Came home and pulled in the garage to check and top off the tranny fluid while the car was idiling in N then it dies and won’t fire back up.

This comment struck me, as I just recently experienced the same thing. Long story short, the reluctor gap was a bit too large. Readjusting it to .008 made a big difference. Probably not your problem, but since I did not see it mentioned previously, I thought it might be worth an honorable mention. Can't hurt to check it. Just be sure to use a brass feeler gauge.

 

[67 Coronet Conv]

This comment struck me, as I just recently experienced the same thing. Long story short, the reluctor gap was a bit too large. Readjusting it to .008 made a big difference. Probably not your problem, but since I did not see it mentioned previously, I thought it might be worth an honorable mention. Can't hurt to check it. Just be sure to use a brass feeler gauge.

Thanks, I adjusted it about 50 miles ago. I’ll re check it. Think this could be failing when it gets hot and may need to replace it

 

[Carcinogen]

I was having ignition problems with stock type ECU and Ballast resistors along with factory wiring that was corroding internally (found corrosion after replacing it). Got fed up chasing my tail replacing components and ended up using HEI module mounted on firewall with remote ignition coil designed for HEI . New wiring using solenoid for full battery voltage. (using stock electronic Distributor)

Problem now is it does not sound like a Dodge starting up. With the mini starter, give it a pump of gas wait a moment hit the key and HEI fires right up, no more starter gear noise while it cranks while trying to fire.

Had considered MSD box but quality seems to have gone downhill lately and HEI modules are easy to find and not too expensive. If you are worried about looking stock the module can be hidden.

 

[Geoff 2]

Yep, hard to beat the GM HEI for price, simplicity & ign performance.