Go-Devil evaluation help needed

[Ryan_M]

I have two motors for my M38 project and I need some help sorting out how to deal with them.

Engine #1
Pros:
Ran great for 1300 miles this year in the M38.

Cons:
Has the wrong head which I don't want to swap until I have to for fear of screwing up a good running motor (snapping a head/manifold bolt, etc) .
Bubba converted to 12V. Wrong starter, alternator, and other junk.

Engine #2
Pros:
Has the correct head and most of the "correct" M38 stuff.

Cons:
I have no idea if it runs and no real history on it.

I have enough flywheels and starters so I can match whatever I need with whichever motor I choose. I am willing to have the 24V starter, generator and distributor rebuilt and can put them on either motor.

My real question is what can I do to test the unknown Engine #2 short of installing it, maybe get it running, and trouble shooting from there?

I haven't ruled out doing just that - dropping it onto my chassis, wiring minimally, and seeing if it will run. Before I go through that hassle, are there any tests I can do with it sitting on the garage floor that may indicate whether or not it's worth proceeding any further? It is not seized and that's about as far as my knowledge on trouble shooting an engine on the floor goes. Even if I don't end up using it would be good to know whether I have a reasonably good spare motor or just a boat anchor.

[scoutpilot]

[size=12]Have tried turning the mystery motor by hand?[/size][/b]

[Ryan_M]

[size=12]Have tried turning the mystery motor by hand?[/size][/b]

Yes. It does turn by hand. 

[Bob W]

Is this Jeep going to be a driver? If so I'd just put engine number 1 in it and keep the 12V.

That didn't even answer your question, did it? 

[bretto]

I have seen people run these engines on YouTube, mounted to a frame of sorts on the ground.  You could probably put a mount together out of some lumber and try to get it running on the garage floor.
Is engine #1 out, leaving a vacant spot on the chassis?  If that's  the case, I'd just set the other motor in its place.  No sense in mocking up a chassis to run it when there is a radiator and all the fixins already to go.

[Ryan_M]

Thanks guys. Bob, you didn't exactly answer the question but your comment ties in directly to another question I have.

Bretto, you may be the one to answer this.

I was going to stay with 24V because I have everything required to do so minus the wiring harness. The harnesses are big bucks but I know I can follow the instructions to connect one. If I convert to 12V now I actually have to improvise and be able to troubleshoot wiring - which is a terrifying prospect since I know nothing about it. It sounds like something I could spend a year on and burn up a pile of components in the process.

Is there any sort of "how-to" guide online for converting an M38 to 12V? Bretto, I know you did it and I have flipped through every pic in your rebuild diary. There's a a lot more involved with M38 wiring than there is for 2A's and 3A's. Do I just follow a 3A schematic and make it like that? What about the circuit breakers and other gadgetry? All kinds of scary stuff in there to deal with. I need a simple set of instructions if such a thing exists.

[1955CJ-5]

I like the test stand idea....squidtone built one, it's on page one of his thread....

It sounds like a great opportunity for you to sharpen your welding skills...

Of course it may be easier to mount the engine in a frame...don't you have an extra frame that is stripped?

[scoutpilot]

[size=12]Have tried turning the mystery motor by hand?[/size][/b]

Yes. It does turn by hand.�

[size=12]Have tried turning the mystery motor by hand?[/size][/b]

[size=12]Hard decision. Is the 24V set up on the mystery motor complete? If so, and this will be a solid winter project, if it were me, I might seriously consider biting the bullet and stripping the good known motor of it's 12V system and pulling the head off. I know, you've already indicated a reluctance, but. IF Bubba didn't alter the basic design of the block and IF the replacement head is good, small investment to find out, and the 24V System is complete, put all of that on the known good motor. You could go over to the 503 and ask on their M38 forum for some help.[/size][/b]

[Bob W]

The 24 volt stuff is more difficult to trouble shoot because it is sealed and much more expensive to repair.

Wire it up just like a 6 volt CJ-3A. Just use 12 volt components and it will be 12 volt. Simple and effective.

[Ryan_M]

Of course it may be easier to mount the engine in a frame...don't you have an extra frame that is stripped

I do have a stripped frame that is marginal condition at best. I was thinking it may convert nicely into and engine test stand.

I like the simplicity of Bob's suggestion of 3A wiring as an option.

Whatever route I decide will likely be thrown out the window on a whim and I'll end up doing something completely the opposite at the last minute.

[bretto]

My M38 came to already converted to 12V.  I didn't do anything but rewire the whole rig with my home brew wire harness.  I did add some modern items like a few relays to run my signals and ran everything thru a blade fuse block.
I can provide a schematic if it would give you any ideas.
If you do decide to go 24V, there are great guides available on working with that sort of system.  I wouldn't be afraid of it.

[Ryan_M]

I can provide a schematic if it would give you any ideas.

If you happen to have one handy I'd love to take a look at it. Don't draw one up just for me though.

[bretto]

I have it in a digital form.  I'll send it later.  Heaing out the door right now.

[Jeff_M]

My vote is for engine #1, only because I've driven it and it is a very good runner.  Put an overdrive on it and it'll probably go 70.  I didn't know the head wasn't correct.  I'd save #2 and come up with some sort of test stand and do a compression check for starters.  If it's weak, well, you've done everything else with these Jeeps, now here's a chance to learn about engine rebuilds, which you could do at your leisure. 

Can you spell "three bay garage"?