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M201 conversion from 24v to 12v


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I want to drop the voltage on my hotchkiss from 24v to 12v.

 

As far as I can see the main stumbling block is the starter motor. I understand the number of dog teeth are different on a 24 volt starter motor, is this correct? If it is how do I get round it?.

 

I intend to go for a 12v alternator and change the distributor.

 

reason for looking at this is to clear the engine bay and make it easier/ cheaper to get parts. Some 24v stuff costs an arm and a leg. Better to change now than wait for big things like the regulator to fail.

 

Anyone done it and have any advice?

 

Doug

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The number of teeth on the M201 starter are the same as MB/GPW. The M38 had a bigger ring gear if i remember correctly.

I just fitted a modern denso starter to my Hotchkiss/Willys salad jeep, it was cheaper than a repro original style and a much better quality, provided your not worried about the original look they are a great alternative. i will be getting another made it a couple of weeks if your interested i could get an extra one done at the same time.

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The number of teeth on the M201 starter are the same as MB/GPW. The M38 had a bigger ring gear if i remember correctly.

I just fitted a modern denso starter to my Hotchkiss/Willys salad jeep, it was cheaper than a repro original style and a much better quality, provided your not worried about the original look they are a great alternative. i will be getting another made it a couple of weeks if your interested i could get an extra one done at the same time.

 

sounds good. I'm interested, how much would it cost for the starter motor?

 

I've got a distributer and 12v coil and saw a guy selling kits for the alternator change if the bracket holding the alternator to the M201 block is the same as for a GPW.

 

 

doug

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You will need to change the bracket if you buy the kit other than that just make your own

it isn't that hard when you buy your alternator pick one that is a popular model i.e. from

a popular car in the scrap yard that way you will have a plentiful supply of cheap replacements

if you are still looking for a 12 volt starter motor I a spare

commander

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You will need to change the bracket if you buy the kit other than that just make your own

it isn't that hard when you buy your alternator pick one that is a popular model i.e. from

a popular car in the scrap yard that way you will have a plentiful supply of cheap replacements

if you are still looking for a 12 volt starter motor I a spare

commander

 

interested in the starter motor. how much do you want for it?

 

Doug

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I am sorry to jump in to this thread, but i have i think 5 of these starters, which i was told are M38 24V starters. Can any of you M38 or M201 24v owners confirm or otherwise?

The tag reads MHJ - 7102 T and they are marked 24V.

If you need one, they are no use to me....

Regards

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Edited by kpu121265
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  • 8 years later...

Robert U'Ren from willysjeepuk has done a couple of proper 12 volt pre engaged starter mods to a willys and a Hotchkiss ,he didnt like the reduction gear retro fit starters available as they sound harsh and noisy, he decided to get a 24volt pre engaged Hotchkiss m201 starter and sent it of to be re wound internally down to 12 volts It was a terific succsess and starts the jeep quietly and sounds very slick in operation, no more grating on the ring gear once you go for pre enguaged and if you can go for direct drive the quietness of the starter is lovely

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I have also  a jaguar e type 12 volt starter and modified it  as they are cheap and plentiful to buy but this is very involved and you need to be a very good engineer to do it, The gear needs to be cut off the bendix and an old 10 tooth willys jeep gear welded in its place, the support for the end of the shaft has to be cut off so the bell housing can support it and the holes have to be drilled closer together , the very end of the shaft ground down slightly so it will fit the bushing etc etc, I nearly gave up but It is possible to do If you are a good welder and have a very good workshop, probably best to spend the money and have a Hotchkiss m201 starter rewound field windings down to 12 volts, job done, the 24 volt solenoid can be retained and works fine , when I did the jag starter I nearly gave up as its huge and only just fits , the casing needs to be ground down in 2 places for clearance for the mounting bolts and I was fortunate to have a spare bell housing and sandwich plate for constant fitting and checking of free movement, the key thing that caught me out was that I didnt measure the distance from the face of the bell housing bush to the clearance of the flywheel teeth, 1.1/4 inch  this is crucial, If the bendix goes to far forward it will wear the back of the bendix against the flywheel and be noisy on cranking but this can be adjusted by fitting a steel collar to restrict how far forward the gear travels

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more pictures of jaguar 12volt heavily modified starter fitted on willys jeep, seriousely though If you can find a hotchkiss m201 24 volt  starter and have it re wound to 12 volts Its a beautiful upgrade sounds so refined in use and protects the ring gear teeth as its a pre engaged  Bendix not a crash bang wallop type like the originals are, see 3rd picture   

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  • 3 weeks later...

further to my last post the 10 tooth cog ended up having to be changed for a longer one with a narrow neck because the welds on the teeth of the first one i did made the starter noisy as they contacted the flywheeel , to make this hotchkiss  longer cog work i also had to shorten the length of the bendix by 1/8th inch and fit the collar to stop the cog going to far forward when cranking , Its far to involved but is possible If your a good  engineer and have a lathe, you can see more on my website willysjeepuk 

If I can find a readily available 12 volt 10 tooth per engaged starter with the solenoid in the right position, this will be very easy to modify and fit ,  I will keep you all informed If I get any luck finding a more suitable base unit, the original 6volt slam bang starters will destroy your jeeps flywheel teeth eventually and  they sound horrible and destructive in use, especially the ones that have been running with a 12 volt battery.

However did we get away with such slow cranking in the war,   I wonder how many soldiers couldn't start their jeeps quick enough and had to abandon them and run for cover 

the second picture shows the 1950s upgrade pre engaged  Hotchkiss m 201 starter , this is a superb upgrade and so refined, It will protect your ring gear , just the sound of its quiet smooth  in action will confirm this , the only one modification you have to do on this Hotchkiss starter is the change of voltage from 24 down to 12 volts , its original 24volt  solenoid will work  fine on 12 but the internal field windings will have to be changed , Robson and Francis motor rewinds were the people i used to get this done 

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and yes the hotchkiss m201 starter will fit the ford gpw and the willys ww2 jeep engines , also the cj2a and the Hotchkiss m201, you can wire it to key start, floor start or press button start , a Massey Ferguson 135      12 volt alternator also makes a very affordable and easily available  charging unit, you just need to rotate the head flange and modify the bottom rear bracket , put what ever pulley you like on  the end to suit the belt or belts you have its easy   

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  • 1 year later...

If anyone can help me with the denso starter model that fits a Hotchkiss or willys mb , I dont mind some slight modification but looking for 12 volt pre engaged direct drive starters to fit these 12 volt converted jeeps, the Hotchkiss pre engaged 24 volt starter is a superb unit but the rewinding of it from 24volts down to 12 volts is  a long wait and is expensive ,  a Hotchkiss with 24 volts or m38 24 volts  could be converted with just the sparking system dropped to 12 volts , that way everything else stays at 24 volts but the current going to the newly fitted externally mounted 12 volt ignition coil runs through a voltage dropper and is reduced from 24 to 12 volts, I also fit a china ballast resistor after the voltage dropper to get the current down 3 more volts, a bit more because on any vehicle when a dynamo or alternator is running the combined voltage is even higher than the 24 volts   so without the china block ballast resistor fitted a running engine can still push a little to much volts through the dropper

 

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If you have a 6 volt jeep with just the one battery box then a proper 12 volt conversion needs a proper 12 volt pre engaged starter not a re badged 6 volt original style starter, this will be to harsh on the ring gear despite what the suppliers may tell you, pre enguaged 12 volt starter is what you want, a simple 12 volt alternator can be easily mounted on the jeep and pulley size changed to suit the belt thickness, split pulleys can be spaced apart with washers so the thick one piece belts can be used , change the bulbs and disconnect the fuel gauge sender at the tank end (they never work anyway) just look in the top of the tank to see what fuel you have 

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