DU4 magneto question

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Topic author
Guardian1fox2
Posts: 157
Joined: Fri Mar 04, 2022 9:55 pm
First Name: Jacob
Last Name: Fox
* REQUIRED* Type and Year of Model Ts owned: 1923 Speedster (in progress)
Location: Lake Charles, LA.
MTFCA Number: 52087

DU4 magneto question

Post by Guardian1fox2 » Fri May 20, 2022 8:21 am

Currently disassembling the Bosch DU4 magneto and came up with some questions.

The instructions all over the internet don’t include this info it seems; but when reassembling, how do you align the gears? I notice there’s an A and C which I assume is clockwise and anti clockwise, and there’s an A and C on the interrupter housing. I’m guessing when the cutout on the interrupter is over the A or C that’s the alignment there, but where do I turn the distributor gear so that they correlate?

Second question is in regards to timing while driving. I notice on the forum there are those with a linkage to adjust timing on the fly like a normal spark control, and those that do not have them (They have the arm on the magneto…but no linkage on the car.). So is it as imperative to adjust spark while driving like original, or is a DU4 more of a set it where it works best and get away with it? With the side drive I’ll most likely use my starter a lot, but I still want to be able to hand crank if necessary.

It’s cleaning up nicely:
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ABE4ED8D-6BED-4740-BC03-38A75D773F32.jpeg
3A897EBF-876E-4F7E-BDB4-543E6102A378.jpeg
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Topic author
Guardian1fox2
Posts: 157
Joined: Fri Mar 04, 2022 9:55 pm
First Name: Jacob
Last Name: Fox
* REQUIRED* Type and Year of Model Ts owned: 1923 Speedster (in progress)
Location: Lake Charles, LA.
MTFCA Number: 52087

Re: DU4 magneto question

Post by Guardian1fox2 » Fri May 20, 2022 8:26 am

054C64AE-9041-48E6-9749-0DC63F047667.jpeg




Also here are some pics of linkages and such I found searching for reference. Also, I’m curious how I will run wires with my headers in building 🤔:
8E089C96-56C2-4ADB-9EEF-9C940F23C54C.jpeg
2D4528A0-9F7F-46A6-8387-43E630D2DC17.jpeg
D8F16C2D-CBA0-4DD4-A1CB-B22BA2E13A32.jpeg

User avatar

John E. Guitar
Posts: 467
Joined: Sun Jan 06, 2019 2:52 pm
First Name: John
Last Name: Guitar
* REQUIRED* Type and Year of Model Ts owned: 1926 Touring, 1924 Tourer
Location: Ulladulla
Board Member Since: 2012

Re: DU4 magneto question

Post by John E. Guitar » Fri May 20, 2022 8:49 am

Page 23 here:

https://oldcroak.com/magneto-service-ma ... osch-1928/

Being able to adjust the advance while you’re driving is a good thing.


Topic author
Guardian1fox2
Posts: 157
Joined: Fri Mar 04, 2022 9:55 pm
First Name: Jacob
Last Name: Fox
* REQUIRED* Type and Year of Model Ts owned: 1923 Speedster (in progress)
Location: Lake Charles, LA.
MTFCA Number: 52087

Re: DU4 magneto question

Post by Guardian1fox2 » Fri May 20, 2022 10:12 am

John E. Guitar wrote:
Fri May 20, 2022 8:49 am
Page 23 here:

https://oldcroak.com/magneto-service-ma ... osch-1928/

Being able to adjust the advance while you’re driving is a good thing.
Man I looked everywhere on that website I can’t believe I missed that! Thank you, that’s going to be very helpful when I reassemble!

Idk how I will get a linkage for the timing advance though, especially with race headers, not mention I may need longer spark plug wires. Perhaps I can reroute throttle to over the block like the adaptor for a model A to use NH, and use the hole in block for the timing somehow.
Last edited by Guardian1fox2 on Fri May 20, 2022 4:20 pm, edited 1 time in total.


Harry Lillo
Posts: 327
Joined: Fri Jan 04, 2019 10:18 pm
First Name: Harry
Last Name: Lillo
* REQUIRED* Type and Year of Model Ts owned: Speedsters, racers, depot hack, coupe
Location: Calgary
MTFCA Number: 13996

Re: DU4 magneto question

Post by Harry Lillo » Fri May 20, 2022 12:21 pm

Jacob,
I believe your timing rod still come around the front of the block, similar to the
conventional Model T timer. There should be no need to re-route that.
Harry


Topic author
Guardian1fox2
Posts: 157
Joined: Fri Mar 04, 2022 9:55 pm
First Name: Jacob
Last Name: Fox
* REQUIRED* Type and Year of Model Ts owned: 1923 Speedster (in progress)
Location: Lake Charles, LA.
MTFCA Number: 52087

Re: DU4 magneto question

Post by Guardian1fox2 » Fri May 20, 2022 4:21 pm

Indeed, I think I can make something relatively easy after looking at a lot of pictures with some bolt on parts! First thing is to get the mag working well lol.

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