Starter pinion gear swap 10 to 9 tooth?

1945 - 196*, Willys CJ series, questions, discussions, regarding anything related to the post war jeep.®
Post Reply
uglyjeep
Sergeant Major of the Gee
Sergeant Major of the Gee
Posts: 457
Joined: Sat Aug 27, 2005 8:56 pm
Location: Mukwonago, Wisconsin

Starter pinion gear swap 10 to 9 tooth?

Post by uglyjeep » Fri Jun 03, 2022 1:20 pm

Hi folks,

Grandpa left my son a CJ-2A project, and we are trying to get it started. It is a collection of different year jeeps, part column shift 2A, part 3A, and some later 2A.

The starter was spinning without engaging the flywheel. After pulling the starter, we discovered that the Jeep has a 124 tooth ring gear on the flywheel and a nice freshly rebuilt, MZ 4113, 10 tooth starter for the CJ2A or MB models. So the jeep needs the 9 tooth starter to work with the 124 tooth ring gear.

The easiest route at the moment appears to just replace the MZ 4113 starter with a 9 tooth MZ 4137 (or MZ 4162 ?), (the aftermarket body has provisions for the manual starter if needed)

Or could I swap the 10 tooth MZ 4113 starter gear for a 9 tooth one and keep the electrical floor switch starter button? I have looked through a few threads here and on the 2A page and more than one person mentions that a 9 tooth gear can be swapped onto the CJ-2A / MB style starters, but is it true?

I am looking for some clarification or help here... Is a 9 tooth gear swap onto the MZ 4113 even possible? The 9 tooth gears that I see for sale are for the MZ 4137 starters with the manual linkage to the starter are a much different set up compared what's on the MZ 4113. Is there a different gear, or perhaps entire bendix assembly, I should be looking for instead?

If I can't figure an easy way out of this I may be in the market for a good used MZ 4137.

Thanks in advance for your time and advice.
Daniel


parker007
G-Colonel
G-Colonel
Posts: 1204
Joined: Fri Oct 18, 2019 4:35 pm
Location: california

Re: Starter pinion gear swap 10 to 9 tooth?

Post by parker007 » Fri Jun 03, 2022 2:34 pm

which bellhousing do you have? one with hole for the starter shaft or the one with a cone on end of starter? from my experience there is 2 styles which flywheel, starter and bellhousing must be swapped together.

uglyjeep
Sergeant Major of the Gee
Sergeant Major of the Gee
Posts: 457
Joined: Sat Aug 27, 2005 8:56 pm
Location: Mukwonago, Wisconsin

Re: Starter pinion gear swap 10 to 9 tooth?

Post by uglyjeep » Fri Jun 03, 2022 3:19 pm

Hi,

This appears to be an early CJ-2A bell housing that has the bronze bushing in the back of the bell housing. The starter from the CJ-2A or our GPW bolts right up to it, and the end of the starter shaft fits nicely in the bell housing bushing. The starter does not have the extended casting to support the end of the shaft.

Thank you,
Daniel
Last edited by uglyjeep on Fri Jun 03, 2022 8:44 pm, edited 1 time in total.

85jeepcj
Sergeant Major of the Gee
Sergeant Major of the Gee
Posts: 455
Joined: Sun Jun 07, 2015 5:58 pm
Location: New Hampshire

Re: Starter pinion gear swap 10 to 9 tooth?

Post by 85jeepcj » Fri Jun 03, 2022 4:13 pm

There are 9 tooth bendix drives available, but they can be difficult to find.

uglyjeep
Sergeant Major of the Gee
Sergeant Major of the Gee
Posts: 457
Joined: Sat Aug 27, 2005 8:56 pm
Location: Mukwonago, Wisconsin

Re: Starter pinion gear swap 10 to 9 tooth?

Post by uglyjeep » Fri Jun 03, 2022 5:43 pm

85jeepcj wrote:
Fri Jun 03, 2022 4:13 pm
There are 9 tooth bendix drives available, but they can be difficult to find.
Thank you, I have heard this mentioned a few times in forum posts, but what application or starter are these 9 tooth bendix drives from? That is what I am trying to find out so I know what to look for.

uglyjeep
Sergeant Major of the Gee
Sergeant Major of the Gee
Posts: 457
Joined: Sat Aug 27, 2005 8:56 pm
Location: Mukwonago, Wisconsin

Re: Starter pinion gear swap 10 to 9 tooth?

Post by uglyjeep » Sat Jun 04, 2022 2:20 pm

I have a little update...but no progress yet.

I found a 9 tooth starter with a GPW marked starter case, but this 9 tooth gear works with the 97 tooth flywheel gear found on the WWII and CJ2A jeeps. Five extra 2A, MB, and GPW starters I own all have 10 teeth. The 9 tooth on the aforementioned GPW starter and the 10 tooth gears all have the same diameter despite different tooth counts

Looking at some sources the 9 tooth gear used in the CJ-3A that works with the 124 tooth ring gear is smaller in diameter than those used on WWII and 2A models.

Thanks again for any help you can provide,
Daniel

User avatar
W. Winget
LTC, U.S. Army
LTC, U.S. Army
Posts: 4438
Joined: Mon Dec 16, 2002 10:37 am
Location: USA, Virginia, Carrollton
Contact:

Re: Starter pinion gear swap 10 to 9 tooth?

Post by W. Winget » Sat Jun 04, 2022 7:03 pm

Search through the generator posts, I recall the starter and bendix of the later L134's used in generators and welder sets like Hobart used different flywheels and hence different Bendix's.
Sounds like you may have a generator flywheel possibly.
V/R W Winget
Looking for 1918 Standard B 'Liberty' truck parts

Steve Webb
G-General
G-General
Posts: 16659
Joined: Fri Jan 17, 2003 3:40 pm
Location: Fort Myers, Florida

Re: Starter pinion gear swap 10 to 9 tooth?

Post by Steve Webb » Sun Jun 05, 2022 1:28 am

What is the diameter of the gear you need?
Stand for the Flag, Kneel for the Cross Psalm 55; 9-11

parker007
G-Colonel
G-Colonel
Posts: 1204
Joined: Fri Oct 18, 2019 4:35 pm
Location: california

Re: Starter pinion gear swap 10 to 9 tooth?

Post by parker007 » Sun Jun 05, 2022 1:48 am

if it was me just split engine and put correct flywheel in. 1/2 days work and you done

uglyjeep
Sergeant Major of the Gee
Sergeant Major of the Gee
Posts: 457
Joined: Sat Aug 27, 2005 8:56 pm
Location: Mukwonago, Wisconsin

Re: Starter pinion gear swap 10 to 9 tooth?

Post by uglyjeep » Wed Jun 08, 2022 3:16 pm

parker007 wrote:
Sun Jun 05, 2022 1:48 am
if it was me just split engine and put correct flywheel in. 1/2 days work and you done
Putting the correct starter back in is less than ten minutes though... :wink:


Post Reply

Return to “CJ Technical Knowledge Base”

Who is online

Users browsing this forum: No registered users and 15 guests