6.2L wiring harness

[dmoon]

Hello all. Just joined!

Had a question. I currently have a 1986 6.2L motor that i just picked up. it is from a military vehicle and it has the 24v starter. and has dual alternators. and the engine came with no wiring harness. My question is first, does someone have one that they would be willing to let go. second, has anyone built one? and third is there a diagram of WHAT and HOW to wire the motor? what all is 24V? starter? glow plugs? fuel shut off solenoid? hi idle/fast idle? and how do the alternators wired?

Thanks alot!

 

[galeo7171]

I bought a complete wiring harness from hillbillyWizard.com

Wasnt hard to install.

 

[Warthog]

Welcome to the site.

What are you installing the engine into? If it is a civvy vehicle there is no need for the 24v stuff.

The stock CUCV is a 12v/24v hybrid. The dirver side alternators is for the 12v side and the passenger is for the 24v side.

You can get all the CUCV technical manuals for free from the link at the top of the page. They are called TM 9-2320-289-xx. The parts manuals end with "P".

The wiring diagrams are in the appendix of the -20 and -34 manuals.

 

[dmoon]

Great thanks. Yes this engine is going to an offroad use only truck. So the only thing that uses 24v on the motor is the starter?
thanks

 

[Recovry4x4]

Simply add a 12V starter and you are golden. The alternators are isolated ground so if you swap them out for something more current, offer up the alts and brackets for sale. There are always buyers for that stuff.

 

[Warthog]

If you end up using one of the "isolated ground" alternators, there is a special way to wire it.

Most civvy alternators use the case for ground. The "isolated ground" units do not. They use a ground stud. All that is needed is to run a ground wire from the stud to the engine block. They rest of the wiring is standard.

If you are putting it in the off road truck, you may just want to install a one-wire unit. The brackets are sized for the type 27si AC Delco alternators.

The injector pump fuel shut off should be 12v. The glow plugs are 12v. Only the starter is 24v. You can get a 12v version just about anywhere. Just make sure you use the proper support bracket. If not, then you run the risk of breaking starter bolts, the flywheel, the starter and even the engine block.

 

[dmoon]

Great. sounds like that is the way to do it. Now just to be a pain. say I wanted to keep it 24V. And I wanted to run the glow plugs on a manual circuit. do i need to go off of the resistor circuit? sorry to be difficult.

 

[Recovry4x4]

If you make your entire vehicle 24V then you could use the drop resistor. The CUCV itself used both voltages. From the factory it had the resistor to drop the voltage for the glowplugs. Many folks move the supply to the buss on the firewall which is 12V. If you make it a hybrid 12/24V system you can run them off the 12V side.

 

[Warthog]

The stock plugs where 12v. GM used the resister pack on the firewall to reduce the 24v down to 12v.

You can buy 24v Humvee (HMMWV) glowplugs if you want.

If you go to a straight 24v, you will need the following:

24v diesel starter
24v glow plugs
24v fuel shutoff

and 24v for all your other electrical items

 

[dmoon]

Just read the article on Isolated Ground theory in the sticky's. good information. i understand much better. thanks guys.

conclusion. sounds like the best bet here is just get a 12v starter, remove the 24v alternator and be done with it
thanks again

 

[Warthog]

Cheapest and easiest for the project your doing. Keep us posted. (along with pictures)

 

[dmoon]

You can get a 12v version just about anywhere. Just make sure you use the proper support bracket. If not, then you run the risk of breaking starter bolts, the flywheel, the starter and even the engine block.

What did you mean by the "proper support bracket" shouldn't there only be one that bolts on?

thanks

 

[Warthog]

No. The diesel engines have three points of support. The two special starter bolts with the crosshatched shafts and a bracket on the other end. Because of the high compression of the engine, the amount of torque applied to the starter requires the extra bracing



gear reduction on the left and direct drive on the right.

This is what can happen to a block when the starter starts moving around. The mounting ear can break off.

 

[dmoon]

OK. I have the original 24v starter still. and it should still have the original brackets on it. So I can just transfer the brackets over from the 24v to the 12v starter.?. also from personal experiences does anyone have any preference on a 12v starter?

 

[Warthog]

The brackets go missing over the years as a lot of people think they are unnessisary. Your might still be there.

There are two types of starters. The older direct drive and the newer gear reduction. Each of them require a different bracket. It doesn't matter if the starter is 12v or 24v, just the type.

Between the 24v and 12v versions, for what you are using them for either will work. The 24v can crank a little harder but is more expensive to buy.

The 12v version is more available and is used in millions of vehicles. A little less expensive to buy.

To rebuild either, the cost is about the same.

Here is a picture of the two types, gear reduction on the left and direct drive on the right.




As you can tell I have spent a LOT of time with the 6.2L engines and have many pictures stored on my computer.

 

[dmoon]

Ok. So, In your opinion, the 12v starter, just go to o'rielly's and pick one up, or specific brand? We see some fairly extreme trail use. And i want reliablity over anything. but on the flip side.... cost is always a factor.

Thanks again.

 

[Warthog]

The ones at Oreilly's are rebuilt gear reductions. They should be in stock. Get the one with the lifetime warranty for the same price.

You will need to get the support bracket from your GM dealer (unless you already have the correct one).

Read this thread for all the GM part numbers

http://www.steelsoldiers.com/showthread.php?15551-Starter-bracket-bolt-size