Rebuilding 1912 Heinze Coils

[Darren J Wallace]

While my hand heals from surgery, I’m slowly getting back into doing things. I started out this weekend by doing something small and light, and for myself. I’ve had an unrestored spare set of late 1912 Heinze ignition coils for my [October 1912 build] 1913 Canadian Ford. I decided to rebuild them. Since my car is a very unrestored cosmetically, but very well maintained, and running car, my coils won’t be visually mint condition but mechanically they will be like new. Completely gutted with new primary and secondary windings used for the later Ford model T coils available from Lang’s or Snyder’s, and new correct capacitors. The original contact points have been carefully removed and new ones installed. Now that they have been calibrated on Mike Kossor’s awesome Heinze edition ECCT unit, I will be able to fill them with tar and they’ll be as good as new for the next 100 years!
These coils work very reliably! The set currently in my car has been giving me flawless performance for quite a few seasons with thousands of miles!

My grandfather bought this car from the original owner in July 1956 who purchased it new in November 1912

[Moxie26]

Darren... Keep up the good work !

[Russ T Fender]

Darren what did you use to open the case?

[love2T's]

I love my Heinze coils in my '13. Over 19,000 miles on them and not had to do anything. But...if I ever feel a need to "tune them" maybe I can hire you!

[Mark Gregush]

The primary center core from the later coils is longer, how did you trim the end to fit the Heinze box?

https://www.modeltford.com/item/5007PR.aspx

[Darren J Wallace]

I used the iron rods from the original Heinze core and very carefully packed the new primary coil as tight as possible. That way nothing needed to be modified.
I opened the case by forcing the side panel apart from the inside where the original capacitor is with a screwdriver and hammer like a pry bar. They mostly come apart without issue but if it breaks I just glue it back together and no one will ever know after careful repair.
The brownish potting material Heinze used is similar to the “cement” used inside pre-1900 Swiss cylinder music boxes that I restore. It’s a recipe of rosin, shellac, and pulverized brick. I actually use type two roofing tar to fill them and save that cement for my music box work.
9 times out of 10, the original cement has lost its bond to the inside of the coil box and there’s actually not that much in them because the original secondary’s took up a lot of room.

[Mark Gregush]

Thank you. I used the rods from the later coil testing things out. I will try the original rods but was not sure if I could get them back in the new primary after playing pick-up sticks.

[Darren J Wallace]

No problem! It’s time consuming but you only have to do it for four coils I get them tight enough that you need to lightly tap the last ones in with a brass hammer very carefully, then I tie them up tight with mechanical wire at each end to prevent migrating. You can separate the original core rods with some light persuasion in your bench vise. They’re coated in paraffin wax which helps get them all in their new home. Three original cores is more than enough iron rods for 4 new coil cores.
The set in my car is 6 years old. No issues.