Rebuilding a 24v starter so it is 12v??? Possible or Not.

[dconn22]

I'm new to this so easy on me...
Not sure if it is true, but I read the other day that it was not difficult to convert a 24v starter to 12v [the actual starter]. I have searched and not found any info to support this. Anyone know if it is possible and if so an economical alternative if one is going 100% 12 volt [which I am seriously considering]. Also, if it is possible can it be done on both GR & DD starters? Thanks.

 

[msgjd]

There are a couple possible scenarios involving your question:

If you want to convert your whole vehicle to 12V, you will be money ahead to put a civilian 12V starter on it instead of trying to convert the 24V starter to 12V. That's IF there is even one that fits that engine. I don't have off-hand knowledge of that parts availability.

If you have no choice but to use your 24V starter casing for whatever reason, a good shop can replace the field coils, and might have to also replace the armature (rotating center). That's IF there are commercially-available 12V internals that fit your casing and application. Again, I don't have off-hand knowledge of the availability of those particular parts. So to answer your questions, Your starter rebuild/conversion IS possible if components are available. Is it economical? No, if there is a commercial 12V starter that already fits your application.

Another scenario related to your situation; You likely won't have to convert your vehicle to 12V just to run a 12V starter. A 12V starter has heavier windings and core than a 24V starter of same HP output, in order to carry the higher amperage and provide the same torque. Likewise, so do 6V starters compared to 12V. It's basic electrical science. Thus, 6V starters spin faster and survive longer on 12V than they will on 6V. (But if cranked continuously, they get hot faster than normal, and overheating will damage it). I have been running 6V starters on 12V in farm tractors and 1950's trucks for over 45 years with 100% success. All still have the original starters, albeit I've had to replace brushes, bushings, and a good cleaning once or twice over the decades. The same science should apply to a 12V starter on a 24V system, however I have never had any need to try a 12 on 24.

In time, other responses will come in. I know of a police dept that had starter issues on their CUCV's, and if I remember the conversation correctly, they were able to get 12V starters that fit. But it's hard for me to trust recent memory

 

[TGP (IL)]

Just find a 12Volt starter for a 1984 K30 6.2 diesel truck.
All the chain stores will have or get it.
Core might be a problem.

Too much $$$ to convert a 24v to 12

Tom

 

[dconn22]

There are a couple possible scenarios involving your question:

If you want to convert your whole vehicle to 12V, you will be money ahead to put a civilian 12V starter on it instead of trying to convert the 24V starter to 12V. That's IF there is even one that fits that engine. I don't have off-hand knowledge of that parts availability.

If you have no choice but to use your 24V starter casing for whatever reason, a good shop can replace the field coils, and might have to also replace the armature (rotating center). That's IF there are commercially-available 12V internals that fit your casing and application. Again, I don't have off-hand knowledge of the availability of those particular parts. So to answer your questions, Your starter rebuild/conversion IS possible if components are available. Is it economical? No, if there is a commercial 12V starter that already fits your application.

Another scenario related to your situation; You likely won't have to convert your vehicle to 12V just to run a 12V starter. A 12V starter has heavier windings and core than a 24V starter of same HP output, in order to carry the higher amperage and provide the same torque. Likewise, so do 6V starters compared to 12V. It's basic electrical science. Thus, 6V starters spin faster and survive longer on 12V than they will on 6V. (But if cranked continuously, they get hot faster than normal, and overheating will damage it). I have been running 6V starters on 12V in farm tractors and 1950's trucks for over 45 years with 100% success. All still have the original starters, albeit I've had to replace brushes, bushings, and a good cleaning once or twice over the decades. The same science should apply to a 12V starter on a 24V system, however I have never had any need to try a 12 on 24.

In time, other responses will come in. I know of a police dept that had starter issues on their CUCV's, and if I remember the conversation correctly, they were able to get 12V starters that fit. But it's hard for me to trust recent memory

Thank you msgid, I figured it was an alt/starter shop thing. It is a J code 6.2 so 12v starters are available.

 

[dconn22]

Still open to more info.
Had a chance to get under it today due to temp work stoppage on GP re-wiring.
My next starter issue is the starter currently installed is what I believe is a direct drive unit; it has the large motor housing with internal retaining bolts. the truck had an additional starter behind the seat that looks new/rebuilt, it has the smaller motor housing with external retaining bolts [gear reduction type]. it has no markings on it of any kind, appears to have had a re-builders sticker on it but it has been mostly torn away and shows no numbers. there are 2 or 3 brackets on the frame that look as though they need to be removed to get the larger starter out so maybe the PO was going to change the starter but discovered these brackets/shields and had second thoughts. Is there any visual clues that distinguish 24v from 12v on the small motor [GR] starter.
If I am not identifying the DD and GR type starters correctly someone please correct me.
Are there DD & GR starters in 12 volt?

 

[cucvmule]

Yes there are both 12 volt direct drive and gear reduction starters available from AC/Delco.

I have an 82 K30 that I went to gear reduction starter, lighter and easier installation, and I am very pleased with it. I have probably 15 plus years on it now. Went to Chevrolet dealer and bought a few starter brackets also. Maybe the last ones, but I see new ones are available again from other sources.

I see no reason to change to 12 volt on the CUCV as the 24 volt does just fine as is. I am positive that there is a rebuild shop in the Great Republic of Texas, Dallas that can rebuild either starter you have. But I would opt for the gear reduction as long as it is 24 volt.

Just wondering how much of the truck is still original, and whether or not keeping the truck as Military issue is still possible. Just by giving the truck some attention goes a long way. Just start by cleaning grounds and pull connections apart and clean and reconnect goes a long way to have systems working.

Good Luck dconn22

 

[dconn22]

it is pretty original which is part of the problem and seems to have had some wiring patch/repairs. it does not look like it has seen a lot of mechanical love but seems to be a good foundation.

 

[cucvmule]

Good foundation, that is a good beginning.

Now it is a decision to stay with 24 or switch to 12 volt. With the intention of staying with Military truck restoration or with modifying truck to have more creature comforts.

 

[cucvrus]

there are 2 or 3 brackets on the frame that look as though they need to be removed to get the larger starter out

There is no need to remove any brackets from the frame. The only bracket that needs removed is the starter support (rear of starter, front of truck) bracket. That is an M8 metric bolt into the block and a 1/4" support stud/bolt on the back face of the upper starter. Both DD & GR have the support bracket. It is required. Back in the beginning I used to remove the flywheel cover and front U joint from the yoke to gain access. Now I just lay on the ground and reach up and change it. Just a few tools and about an hour at most. You should be good. remember to replace the starter bolts and they are M10metric. Not 3/8" 3/8" will fit and get semi tight. I have found these in several trucks. Same as block bolt. Not 5/16". That is M8 metric. Good Luck. Report back. Have a Great Happy Thanksgiving.

 

[DeadParrot]

There are geared drive starters in 12V. Found one on my M1008 being fed 24V to the starter and 12v to the solenoid. It was a China made Delco unit that had a nice sticker. Replaced with 24v geared drive and fixed the PO modified cab starter wiring.

NOTE: the support brackets are different between the direct drive and geared drive starters. If you swap types, get the proper front bracket.

 

[gimpyrobb]

I didn't see anyone mention if you change to 12v, your amp draw will go up and you need wires that can handle the higher current so you dont set your vehicle on fire.

 

[MarcusOReallyus]

I didn't see anyone mention if you change to 12v, your amp draw will go up and you need wires that can handle the higher current so you dont set your vehicle on fire.

Yes, please.

I am convinced that all of the bellyaching that we have heard about 12v starters not working as well is simply due to the fact that people rearrange the existing wiring to run the 12v starter. It's not adequate. It's sized for 24v. There are a bazillion diesel trucks out there running 12v starters with no problems, but they have the bigger cables to do the job.

 

[richingalveston]

just remember to disconnect the batteries when working on the starter, That wire is hot all the time.
I like the stock 24volt starter, but the 12 volts work just as well
I was able to get the stock starter rebuilt for about $200 which is more than what the 12 volt starter cost.
but once you factor in the new wires, it is about the same.