Bosch DU4 - Correct For A Model T?

Discuss all things Model T related.
Forum rules
If you need help logging in, or have question about how something works, use the Support forum located here Support Forum
Complete set of Forum Rules Forum Rules
User avatar

Topic author
Tim Rogers
Posts: 387
Joined: Sun Jan 06, 2019 11:04 am
First Name: Tim
Last Name: Rogers
* REQUIRED* Type and Year of Model Ts owned: 1925 Coupe & 1923 Runabout
Location: South of the Adirondacks
Board Member Since: 2013

Bosch DU4 - Correct For A Model T?

Post by Tim Rogers » Fri Dec 18, 2020 8:26 am

I want to install a Bosch magneto and have acquired the mounting bracket below. Are all Bosch DU4s the same or am I looking for something specific? Any help would be appreciated.

bosch.jpg
bosch.jpg (8.57 KiB) Viewed 3331 times
<o><o><o><o> Tim Rogers - South of the Adirondacks - Forum member since 2013 <o><o><o><o>

User avatar

George House
Posts: 2270
Joined: Sun Jan 06, 2019 5:25 pm
First Name: George
Last Name: House
* REQUIRED* Type and Year of Model Ts owned: ‘10 Maxwell AA, ‘11Hupp Model 20, Two 1914 Ford runabouts, 19 centerdoor, 25 C Cab,26 roadster
Location: Northern Caldwell County TX
MTFCA Number: 115
MTFCA Life Member: YES
Board Member Since: 1999

Re: Bosch DU4 - Correct For A Model T?

Post by George House » Fri Dec 18, 2020 9:18 am

They’re basically the same except the base is cast brass on early DU 4s and cast aluminum on later mags. I think both will fit.
I don’t know why I turned out this way. My parents were decent people 🤪


Jerry VanOoteghem
Posts: 2952
Joined: Sun Jan 06, 2019 4:06 pm
First Name: Jerry
Last Name: Van
Location: S.E. Michigan
MTFCA Number: 24868

Re: Bosch DU4 - Correct For A Model T?

Post by Jerry VanOoteghem » Fri Dec 18, 2020 9:53 am

Do yourself the favor of either buying one that's been rebuilt, or having one rebuilt. Rewound armatures, new condensers and freshly charged magnets make all the difference. Even with one that is original and works great, you still run the risk of throwing off the old armature windings and having the mag seize up.

User avatar

Mark Gregush
Posts: 4956
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, 1920 Dodge touring, 1948 F2 Ford flat head 6 pickup 3 speed
Location: Portland Or
MTFCA Number: 52564
Board Member Since: 1999

Re: Bosch DU4 - Correct For A Model T?

Post by Mark Gregush » Fri Dec 18, 2020 10:10 am

Make sure the rotation is correct. They come in clockwise and counter clockwise rotations. There should be an arrow on the oiler on top of the housing. Looking from the front when mounted, it would be a clockwise rotation, the arrow pointing to the engine, turning the same direction as the crankshaft gear/engine.
I know the voices aren't real but damn they have some good ideas! :shock:

1925 Cut down pickup
1920 Dodge touring
1948 Ford F2 pickup


Dropacent
Posts: 3384
Joined: Sun Jan 06, 2019 11:39 am
First Name: Tim
Last Name: Morsher
* REQUIRED* Type and Year of Model Ts owned: 1925TT, 1926 Martin-Parry bodied wagon, 1927 mercury bodied speedster
Location: Norwalk Ohio

Re: Bosch DU4 - Correct For A Model T?

Post by Dropacent » Fri Dec 18, 2020 10:42 am

You cannot rely on the oiler arrow, as all units are easily changed rotation. The points set is held by a long hex nut, change that , reset the brass gears and rotation is changed.


flatbroke3
Posts: 53
Joined: Sun Jan 06, 2019 11:21 am
First Name: harold
Last Name: musolf
* REQUIRED* Type and Year of Model Ts owned: 1911 touring 1926 touring 1913 touring
Location: seattle
MTFCA Number: 51354
Board Member Since: 2010

Re: Bosch DU4 - Correct For A Model T?

Post by flatbroke3 » Fri Dec 18, 2020 11:02 am

if you do change the rotation of the armature you also have to change the points out with the correct set, for that rotation. they made the points in both c.w. and c.c.w. rotation.
Harold III


flatbroke3
Posts: 53
Joined: Sun Jan 06, 2019 11:21 am
First Name: harold
Last Name: musolf
* REQUIRED* Type and Year of Model Ts owned: 1911 touring 1926 touring 1913 touring
Location: seattle
MTFCA Number: 51354
Board Member Since: 2010

Re: Bosch DU4 - Correct For A Model T?

Post by flatbroke3 » Fri Dec 18, 2020 11:07 am

oops, I guess I should have read the post that Dropacent posted more carefully, it does tell you to change the points. my bad.
Harold III


Dropacent
Posts: 3384
Joined: Sun Jan 06, 2019 11:39 am
First Name: Tim
Last Name: Morsher
* REQUIRED* Type and Year of Model Ts owned: 1925TT, 1926 Martin-Parry bodied wagon, 1927 mercury bodied speedster
Location: Norwalk Ohio

Re: Bosch DU4 - Correct For A Model T?

Post by Dropacent » Fri Dec 18, 2020 8:31 pm

Tim, shown is the right point sets inside the mag. That set is clockwise. Shown on the backside , one is marked “C” for clockwise. The other “A” denoting Anti-clockwise. That is how Bosch referred to them. If you need a copy of the manual, let me know and I can email it to you. It answers everything you need to know to set it up correctly.
From memory, the 3 gear side drive setup uses an Anti-clockwise mag. The side drive like you show, and all the front mag drives use the Clockwise mag. If not correct, hopefully someone will shout out. If you don’t fool with these all the time, the info leaks from my brain. The recent Bosch mag shelf that I made up, I’m not sure of rotation required. Need to map it out someday.
ECFB7259-CB14-45B6-B765-E8016316BC91.jpeg


Dropacent
Posts: 3384
Joined: Sun Jan 06, 2019 11:39 am
First Name: Tim
Last Name: Morsher
* REQUIRED* Type and Year of Model Ts owned: 1925TT, 1926 Martin-Parry bodied wagon, 1927 mercury bodied speedster
Location: Norwalk Ohio

Re: Bosch DU4 - Correct For A Model T?

Post by Dropacent » Fri Dec 18, 2020 8:35 pm

“A” means anti-clockwise , also counterclockwise. “C” means clockwise
89D6562F-8621-4C5D-8447-E414A8ADF87D.jpeg


dmdeaton
Posts: 730
Joined: Mon Oct 21, 2019 9:43 pm
First Name: Danny
Last Name: Deaton
Location: Ohio

Re: Bosch DU4 - Correct For A Model T?

Post by dmdeaton » Fri Dec 18, 2020 8:40 pm

Clockwise from the drive end, correct?

If the crankshaft turns clockwise looking at the front then the camshaft turns opposite which would drive the mag anti clockwise. Referring to Tim’s new mag plate and belt driving it. Correct, maybe??

User avatar

Susanne
Posts: 1045
Joined: Sat Apr 13, 2019 6:06 pm
First Name: Susanne
Last Name: Rohner
* REQUIRED* Type and Year of Model Ts owned: Late '15 touring, "Angel".
Location: Valfabbrica, (central) Italy
MTFCA Number: 464
MTFCA Life Member: YES
Board Member Since: 1999
Contact:

Re: Bosch DU4 - Correct For A Model T?

Post by Susanne » Fri Dec 18, 2020 8:51 pm

The part that always confused me is if it's CW FACING the gear on the front of the mag, or CW as if you were facing the back of the mag (like sitting on top of the mag if you were a gnome)... It's not the first time I've tried to suss this out and yet it still perplexes me... Is it facing the gear, or facing the back of the mag? ARRGHHH!!!! :lol:

On a direct drive (like yours) or one of those cool left-side chain (or belt) drive pedestal mounts, the mag will turn the same direction as the crankshaft (opposite the direction of the cam gear). On (most) crossdrives, it's the opposite.

User avatar

Mark Gregush
Posts: 4956
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, 1920 Dodge touring, 1948 F2 Ford flat head 6 pickup 3 speed
Location: Portland Or
MTFCA Number: 52564
Board Member Since: 1999

Re: Bosch DU4 - Correct For A Model T?

Post by Mark Gregush » Fri Dec 18, 2020 9:18 pm

Crank shaft from the front, clockwise, camshaft counter clockwise, generator or in this case single gear driven mag drive would be clockwise. Direction would be at the gear or driven end, so looking at that end of the magneto.
Thanks for the information on the markings. That makes it easy to swap them over if needed.
I know the voices aren't real but damn they have some good ideas! :shock:

1925 Cut down pickup
1920 Dodge touring
1948 Ford F2 pickup

User avatar

Duey_C
Posts: 1518
Joined: Sun Jan 06, 2019 12:28 pm
First Name: Duane
Last Name: Cooley
* REQUIRED* Type and Year of Model Ts owned: 18 Runabout, 24 Runabout for 20yrs, 25 TT, late Center Door project, open express pickup
Location: central MN
MTFCA Number: 32488
Board Member Since: 2015

Re: Bosch DU4 - Correct For A Model T?

Post by Duey_C » Fri Dec 18, 2020 9:38 pm

Yes, Clockwise or anti-clockwise when looking at the drive end. :)
Tim, those pics are gold for many people! May I steal them for my magneto records? Serious question. I don't know if I've seen that before!
Which manual do you have? Very curious. PM me if you feel it more comfortable.
oldcroak has graciously provided me with many magneto manuals. A God-send.
For impulse coupler users, most times that part's cake as the parts are marked like those "jewel pics" of the points plate.
Just flip the parts (and the spring) around so you see the A or the C/AC as your needs dictate.
Replace the interrupter (points) plate, re-time the gears and set the impulse coupler.
Susanne, I sure get ya there! In the driver's seat verses standing at the front. I've struggled with that also.
Mags are viewed with the mag in your hand or on the bench and the drive end or impulse coupler facing you.
In time, I'll need an anti-clockwise DU-4 for an OT project.
Gosh, I need to read this whole thread again! That's a good thing. :)
I'm more of a ZR-4 kind of guy (they are OK for a T also) and the chance to know a DU-4 is coming.
:)
Since I lost my mind mind, I feel more liberated


Dropacent
Posts: 3384
Joined: Sun Jan 06, 2019 11:39 am
First Name: Tim
Last Name: Morsher
* REQUIRED* Type and Year of Model Ts owned: 1925TT, 1926 Martin-Parry bodied wagon, 1927 mercury bodied speedster
Location: Norwalk Ohio

Re: Bosch DU4 - Correct For A Model T?

Post by Dropacent » Fri Dec 18, 2020 10:38 pm

Danny and Susanne, it’s easy to get too tied up in terminology. Especially when one persons clockwise is anothers counterclockwise. Especially when one persons front of the magneto is another persons backside of the magneto. See where I’m going?
To make it easy, the cross drive front mount OR the side unit Tim Rogers posted pictures of, take clockwise points. Picture shown below, and stamped C on the backside. ( is it called a clockwise magneto ? I DUNNO) The 3 gear side drive unit takes a counter(anti)clockwise points stamped A on the backside. This for DU4 units. These units are great because they are so sturdy, bulletproof, easily changed in rotation , and timed just by moving the brass gear teeth. IGNORE THE ARROWS ON THE OILER LIDS !!
You are on your own if you want to use a Dixie, eismann Apollo, Splitdorf or one of many others. K.I.S.S.
C408E94D-AC0F-4DF7-A585-7B509ADBC631.jpeg


Dropacent
Posts: 3384
Joined: Sun Jan 06, 2019 11:39 am
First Name: Tim
Last Name: Morsher
* REQUIRED* Type and Year of Model Ts owned: 1925TT, 1926 Martin-Parry bodied wagon, 1927 mercury bodied speedster
Location: Norwalk Ohio

Re: Bosch DU4 - Correct For A Model T?

Post by Dropacent » Fri Dec 18, 2020 10:40 pm

I’ll post the manual for the DU4 here, Duey. Feel free to pass any of it on, but please let me know if I’m incorrect.


Dropacent
Posts: 3384
Joined: Sun Jan 06, 2019 11:39 am
First Name: Tim
Last Name: Morsher
* REQUIRED* Type and Year of Model Ts owned: 1925TT, 1926 Martin-Parry bodied wagon, 1927 mercury bodied speedster
Location: Norwalk Ohio

Re: Bosch DU4 - Correct For A Model T?

Post by Dropacent » Fri Dec 18, 2020 10:52 pm

BE5D390F-CE0B-4B2C-BEAC-2AA793FDB91F.jpeg
1C6AA6D9-96A2-4206-8F23-AB0C3AC17185.jpeg
910CC6E9-97C7-4DD0-852F-1FB0C1D82629.jpeg
9077793C-2AAC-4E5F-9066-49C9FBD6F285.jpeg
5E30691B-3F3E-4B6A-B889-C52CC8907A8B.jpeg


Dropacent
Posts: 3384
Joined: Sun Jan 06, 2019 11:39 am
First Name: Tim
Last Name: Morsher
* REQUIRED* Type and Year of Model Ts owned: 1925TT, 1926 Martin-Parry bodied wagon, 1927 mercury bodied speedster
Location: Norwalk Ohio

Re: Bosch DU4 - Correct For A Model T?

Post by Dropacent » Fri Dec 18, 2020 10:53 pm

E7771B14-D965-406C-81AA-47F188489A68.jpeg
F37667FA-C99B-44F0-B1D0-20D77FCB85EA.jpeg
ACB20C46-9557-423D-A711-2E37040D3FAC.jpeg
0D622B7E-5B37-4394-B1FF-E7B50EA75287.jpeg
B80C3671-D33F-49FF-A09C-45C7A242BD71.jpeg


Dropacent
Posts: 3384
Joined: Sun Jan 06, 2019 11:39 am
First Name: Tim
Last Name: Morsher
* REQUIRED* Type and Year of Model Ts owned: 1925TT, 1926 Martin-Parry bodied wagon, 1927 mercury bodied speedster
Location: Norwalk Ohio

Re: Bosch DU4 - Correct For A Model T?

Post by Dropacent » Fri Dec 18, 2020 10:54 pm

D9A70EC5-B979-45A1-A1E5-57AE431ED861.jpeg
B68A1992-1883-4986-ABE6-022128CF978D.jpeg
7A1E884D-1094-445A-AEFC-9C4C4271D7A5.jpeg
C8A3668F-3A51-40C9-A6D5-183D01FC338C.jpeg
6C4B9933-AC32-4A31-A77A-84C2D69C2AF1.jpeg


StanHowe
Posts: 979
Joined: Mon Jan 07, 2019 5:42 pm
First Name: Stan
Last Name: Howe
* REQUIRED* Type and Year of Model Ts owned: 2
Location: Helena, MT
MTFCA Number: 19133
Board Member Since: 1999

Re: Bosch DU4 - Correct For A Model T?

Post by StanHowe » Sat Dec 19, 2020 12:40 am

A mag that runs directly off the camshaft gear -- as most do -- will be clockwise, as the cam gear turns counter clockwise.
A mag that runs off an intermediate gear -- such as the Bosch side drive -- will turn the same direction as the camshaft; counter clockwise.

It is easy to forget that the cam gear is turning in the opposite direction of the crankshaft.


dmdeaton
Posts: 730
Joined: Mon Oct 21, 2019 9:43 pm
First Name: Danny
Last Name: Deaton
Location: Ohio

Re: Bosch DU4 - Correct For A Model T?

Post by dmdeaton » Sat Dec 19, 2020 6:44 am

And if belt driven off the camshaft will need to be counterclockwise

User avatar

Topic author
Tim Rogers
Posts: 387
Joined: Sun Jan 06, 2019 11:04 am
First Name: Tim
Last Name: Rogers
* REQUIRED* Type and Year of Model Ts owned: 1925 Coupe & 1923 Runabout
Location: South of the Adirondacks
Board Member Since: 2013

Re: Bosch DU4 - Correct For A Model T?

Post by Tim Rogers » Sat Dec 19, 2020 7:11 am

I appreciate all the info, thanks! I'm in the market for a restored or fully functional clockwise DU4, let me know what you have...
<o><o><o><o> Tim Rogers - South of the Adirondacks - Forum member since 2013 <o><o><o><o>


Dropacent
Posts: 3384
Joined: Sun Jan 06, 2019 11:39 am
First Name: Tim
Last Name: Morsher
* REQUIRED* Type and Year of Model Ts owned: 1925TT, 1926 Martin-Parry bodied wagon, 1927 mercury bodied speedster
Location: Norwalk Ohio

Re: Bosch DU4 - Correct For A Model T?

Post by Dropacent » Sat Dec 19, 2020 11:40 am

I posted Dixie, splitdorf and New York coil manuals here months ago.


dmdeaton
Posts: 730
Joined: Mon Oct 21, 2019 9:43 pm
First Name: Danny
Last Name: Deaton
Location: Ohio

Re: Bosch DU4 - Correct For A Model T?

Post by dmdeaton » Sat Dec 19, 2020 12:38 pm

Who is the fellow that rebuilds these?

User avatar

Mark Gregush
Posts: 4956
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, 1920 Dodge touring, 1948 F2 Ford flat head 6 pickup 3 speed
Location: Portland Or
MTFCA Number: 52564
Board Member Since: 1999

Re: Bosch DU4 - Correct For A Model T?

Post by Mark Gregush » Sat Dec 19, 2020 12:59 pm

Depending on location here is a list on Smokstack some might be closer then others. While it does contain listings for different repairs, there are magneto repair people listed.
https://www.enginads.com/bizcards.shtml
I know the voices aren't real but damn they have some good ideas! :shock:

1925 Cut down pickup
1920 Dodge touring
1948 Ford F2 pickup


Dropacent
Posts: 3384
Joined: Sun Jan 06, 2019 11:39 am
First Name: Tim
Last Name: Morsher
* REQUIRED* Type and Year of Model Ts owned: 1925TT, 1926 Martin-Parry bodied wagon, 1927 mercury bodied speedster
Location: Norwalk Ohio

Re: Bosch DU4 - Correct For A Model T?

Post by Dropacent » Sat Dec 19, 2020 1:02 pm

Jerry has good advice above. This is what works for me. These Bosch DU4 mags are so plentiful ,that I only buy really nice looking ones. I take them apart, clean very well, especially the hardened old oil. I lubricate them, reassemble , and have never yet had one fail or not perform well. Knock on wood ! Another bonus is you really get to know the mechanics of your choice of ignition. I have them on 4 ts Be prepared to spend $4-600 for getting one rebuilt by a pro. I’ll let someone that has paid to have one rebuilt recommend a rebuilder.


dmdeaton
Posts: 730
Joined: Mon Oct 21, 2019 9:43 pm
First Name: Danny
Last Name: Deaton
Location: Ohio

Re: Bosch DU4 - Correct For A Model T?

Post by dmdeaton » Sat Dec 19, 2020 1:12 pm

My thoughts are recharging the magnets.


BHarper
Posts: 221
Joined: Sun Jan 06, 2019 11:15 am
First Name: Bill
Last Name: Harper
* REQUIRED* Type and Year of Model Ts owned: '14 Touring, '20 TT Farm Truck, '24 TT Depot Hack, '24 Coupe, and a 1914 Metz Model 22 Torpedo Runabout
Location: Keene, New Hampshire
MTFCA Number: 5414
MTFCA Life Member: YES
Board Member Since: 1999

Re: Bosch DU4 - Correct For A Model T?

Post by BHarper » Sun Dec 20, 2020 7:33 pm

I always "sit up straight and pay close attention" whenever Bosch DU4 is mentioned. I want to thank all of you who contributed useful information to this thread, especially Tim Morsher for generously sharing the Bosch DU4 manual.

I will be saving all of this technical information for the time when the magneto on my '14 Metz causes disappointment and head scratching.


197f9f3b-af9f-44e5-98af-7212aeb6b37a.jpg

User avatar

Duey_C
Posts: 1518
Joined: Sun Jan 06, 2019 12:28 pm
First Name: Duane
Last Name: Cooley
* REQUIRED* Type and Year of Model Ts owned: 18 Runabout, 24 Runabout for 20yrs, 25 TT, late Center Door project, open express pickup
Location: central MN
MTFCA Number: 32488
Board Member Since: 2015

Re: Bosch DU4 - Correct For A Model T?

Post by Duey_C » Mon Dec 21, 2020 12:13 am

I like threads like this. :) Bill, I'm glad you find this useful! The mere mention of American Bosch mags perks my ears too!
Barring my own "tries" at sharing information with what little I know about these contraptions, stay clear of the wax smoke if you replace the condenser on the "rear" end of the armature with a capacitor. It smells really, really bad and never use sandpaper on the distributer.
Tim R, let us know when you find your magneto. Ya started a good thing here!
Tim M, that is the exact manual I have, jumbled pages and all! Thank you much!
:)
Danny, is Cross lake Township in Maine close to you for recharging your magnets?
I'll admit I've not done business but thought I'd share about Mainely Magnetos there. There are many others also. Done business with some closer to me.
Funny how the antique automobile and old tractor worlds come together. Here there are 4 AB mags in care and upkeep.
:)
Since I lost my mind mind, I feel more liberated


dmdeaton
Posts: 730
Joined: Mon Oct 21, 2019 9:43 pm
First Name: Danny
Last Name: Deaton
Location: Ohio

Re: Bosch DU4 - Correct For A Model T?

Post by dmdeaton » Mon Dec 21, 2020 10:46 am

Duey
I’m outside of Cincinnati but can ship anywhere. At the local museum hangout a fellow is big time into prewar fire trucks. He passed a phone number to me of a fellow he uses. I’m in no hurry, I have 2 builds I need to get finished before adding anything else.😳

Post Reply Previous topicNext topic