I just picked up a case vac wide front that has been converted to 12 volt at one point but has sitting in a field with the exhaust uncovered since 2016 when i was told it supposedly last ran before they took the coil off of it for another machine. I plan on getting it running and fixing any issues it might have and repainting it. What should i try to do to start on getting it running because it is missing the coil and a few other things. I also have no idea on how the hydraulics on it work or function and if they do work or function at all. Any help or tips on getting it running would be appreciated.

The first thing I'd do is remove the spark
plugs and squirt a little oil in each
cylinder. Crack the oil drain plug loose
and back it out far enough to see if any
water or coolant drips out or if only oil
drips. Drain any water present, if any.
Remove the rocker cover and tap on each
rocket arm to make sure the balves aren't
stuck. Then I'd see if the engine turns by
hand. If all of that checks out, I'd change
the oil, top off the coolant if need be and
proceed with replacing the coil and doing
whatever electrical and fuel system repairs
necessary to get it running. IE checking
condition of and cleaning the points, fuel
tank, sediment bowl and screens etc. I'm
sure others will add on anything I might
have missed and might have suggestions
other than mine.

Welcome to YT and may things turn out good. The first essential task is to assess whether it has any chance to free up without removing the cylinder head. Remove the sparkplugs and look at them. if one or more are solid rust, do not try to turn the engine. Next drain the oil (slowly remove the plug on the last few threads) to see if there is water in the oil pan. If so, things are looking like a tear down. The device in the link can be used to look directly into each cylinder to see rust or corrosion. It is cheap and works like a miracle with a smart phone. If nasty rust, you will damage components you need if you try to turn the engine. (assuming you are working inside) at this point removing the oil pan and cylinder head will be a must do.
If there is surface rust and little water in the pan, putting a dose of one of these in the cylinders is a start. Automatic trans fluid, Zep penetrating fluid, PB Blaster spray, Liquid wrench. Put the plugs back in and let it sit for a week. Next with the transmission in road gear, rock the tractor back and forth pushing on the top of the rear tire. This puts light shock load on the engine and may get it loose. Try it again often in the next few days. if no luck, you will probably need to take it apart. Keep us in the loop of activities. Spend some time looking for components missing and discussing it with us.
Endoscope

It turns over freely but leaks just about everywhere. Oil smells a little like gas and the whole engine was coated in old oil where it leaked for years. The pto cover has been taken of before and there is a lot of silicone gasket in places on it which isn't factory. I have a whole parts tractor with a running engine worse case scenario i need to swap.

DC Tom shared something that he used many times with good success . take a old plu that rhreads in there and cut off at pocelon , weld a pipe thread on to the spark plug fasten a hydraulic line to pipe thread, , couple totractor remote ,, on a cylindar on top stroke and the rocker arms off apply power ,,. ... DC Tom was a gifted Case mechanic that pulled successfully DC Case tractors ,.. ,

If it turns over freely, I'd just stick a coil on it, change oil and filter, some fresh gas and see if it runs. You can clean up and degrease the tractor and then assess the oil leaks and such and repair as necessary.

It was missing the fuel line and mud daubers put mud in the fuel line and i assume carb. So the carb is probably gummed up from sitting with gas in it. I will probably pull the bowl and clean the carb and jets. Would any 12v coil work for it?

Looks like it's been converted to 12 volt with an alternator. I'd use a 12 volt coil with internal resistor so you don't have to mess with a ballast resistor.

Not a flame, it is an assumption many make. 12v coils that need no external resistor don't have resistors inside, they are just wound with more and thinner wire to work at 14+ volts. It is like 120 volt light bulbs made to operate at 120 v. Using a proper resistor on a 60 volt light bulb will allow it to operate at 120 volts! Jim

The thing is that they are marketed as having an internal resistor. It may be a misconception, but it is common terminology and common marketing, be it technically correct or not. The point is that no external ballast resistor is needed.

One thing I didn't see anyone mention is that any VAD I have seen has a fitting on the front of the engine for a hand crank. If one didn't come with your VAC, find
someone with the hand crank and see if the engine will turn' If it does, put a coil on it, clean the carburetor, change the oil, and try to start it. It not you need to
unstick the engine.

Also, post oyur questions here but also post them on the case board. A lot of experience and good advice for a VAC there.

Yes, this good investment with cell phone. Not cost that much.
Can use in plumbing, inside stud walls, etc.

Advert people are not engineers. The internal resistance idea is not a lie, the windings do have resistance. The reason for not putting a real resistance device in the case is heat. That is why the external resistors have ceramic blocks. All good. Jim