Heinze coil box restoration

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Woody23
Posts: 76
Joined: Thu Jan 07, 2021 1:40 pm
First Name: David
Last Name: Woods
* REQUIRED* Type and Year of Model Ts owned: 1923 Touring
Location: Williamston
Board Member Since: 2016

Heinze coil box restoration

Post by Woody23 » Sun Feb 15, 2026 10:05 am

This Heinze coil box came in for lid repair. There was a chunk of wood missing on one side. I also noticed one of the contact springs was loose, then broke off.

During the spring replacement I noticed a lot of corrosion around split rivets that hold the springs (see photo) and wire that carries power to the coils. Measuring the resistance on each spring contact revealed one contact had very high resistance, it was measuring 68k ohms. This would essentially stop the coil from working since very little current would get into the primary coil. The other contracts measured 1-3 ohms, this resistance will have a negative effect on coil performance.

So although this coil box would have four rebuilt coils they all would perform poorly due to the resistance inline with the primary coils. I believe this is a bigger issue than owners realize. Most coil boxes are still running with the original hardware. So there is over a hundred years of corrosion and since these contacts are out of sight little attention is given to them.

This can easily be checked with an ohm meter, ideally there should be zero resistance. Testing can be do without pulling the box apart but to repair this the bottom panel with the contacts must be removed. It also a great time to clean the switch. The contacts were media blasted and lubricated with conductive grease. I also made the lettering in the switch white again.

The brass latches were disassembled, cleaned and polished. The wood was stripped, lid repaired, stained and sealed. I also nickel plated the box mounts since they were rusty.

With rebuild coils and box the owner will again enjoy a much better running T.
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User avatar

KWTownsend
Posts: 1520
Joined: Mon Jan 07, 2019 6:51 pm
First Name: Keith
Last Name: Townsend
* REQUIRED* Type and Year of Model Ts owned: late 1911 touring, 1915 runabout, 1919 touring, brass speedster
Location: Gresham, Orygun
MTFCA Life Member: YES
Board Member Since: 1999

Re: Heinze coil box restoration

Post by KWTownsend » Sun Feb 15, 2026 11:49 am

Nice work!

User avatar

Mark Gregush
Posts: 5533
Joined: Sat Jan 05, 2019 1:57 pm
First Name: Mark
Last Name: Gregush
* REQUIRED* Type and Year of Model Ts owned: 1925 cutdown PU, 1948 F2 Ford flat head 6 pickup 3 speed
Location: Portland Or
Board Member Since: 1999

Re: Heinze coil box restoration

Post by Mark Gregush » Tue Feb 17, 2026 1:02 pm

Agree! Good job. I have a Heinze that I need to get off my butt and go through. Thanks for the tips.
I know the voices aren't real but damn they have some good ideas! :shock:

1925 Cut down pickup
1948 Ford F2 pickup

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