Here's just a wild guess, some previous monkey was trying to get the spark plug out and was using a wrench 3 sizes to big and pounded the wrench on and stressed the head and then finally got the wrench off and left it... and then a Darrel came along and the fellow sold him a skidsteer with a stuck plug. After much time the stress relieved itself and let burning gases start escaping in the first crack, then the second crack opened up and then the third...

I got a little Bobcat 610 with a stuck engine and a cracked head, I replaced a head off an older WI power unit.. and it happened to be for a lower compression and later switched the second head also...

 

https://www.machinerytrader.com/listings/construction-equipment/auction-results/28266773/international-3200a" rel="nofollow -

Wheel

28 hp hp; None ROPS; INTERNATIONAL 3200A SKID LOADER 2001 HRS. GAS WISCONSIN ENGINE 55 IN BUCKET DOES NOT RUN!! HAS BEEN SITTING FOR 2 YEARS! LOCATION: GRANT, IOWA Call Katie at Panama Transportation Solutions 1-800-489-2088 Ext 233 For a Trucking Quote Ground Clearance: 8, Bucket Siz...

Price: USD $1,950

Sale Ended: Wed, Oct 17, 2018 11:59 AM

https://www.machinerytrader.com/info/calculator?loan=1950" rel="nofollow -

Hours: 2001

Operating Capacity: 1,250 lb

Serial Number: 2700004V002565

Condition: Used

As to what causes it, spark erosion, spark jumps around electrode, eats a hole in the head.  I fixed one, one weekend, by knockin off a few fins, drillin and tappin the hole, and puttin a short bolt in, slathered in lock tite.  Lasted till new head was obtained, in a coupla weeks...  These were also famous, fer shootin the SP outta the head, damn aluminum heads!

The other thing that causes it, is corrosion forming between the head and spark plug threads.

the spark plug threads are a direct path for cooling the plug electrodes... but it's a mating of dissimilar metals. When the plugs form that little corrosion layer, the rate at which heat can LEAVE the plug, and be dissipated by the cooling fins, slows down, which causes the plug to expand into the threads tighter.  Eventually, the top of the head in the immediate vicinity of the plug heats up higher, and causes the area under the fins to weaken, and the crack forms.  Doesn't take long for combustion gases to burn thorugh the crack and cause those little pits.

The evidence of expansion and thermal trauma are obvious-  notice how the fin is cracked, and BENT?  That's from expansion fatigue.

Most of the time, on skid-steers, you'll find that the cooling shrouds have mouse nests in 'em... (don't ask how I know...) 

What would have been REALLY GREAT...

Is if Wisc made this same engine in an OHV with liquid cooled heads...

It would have had 40% more torque, been less than half the noise, and plenty more durable...

I'm currently repowering an IH 4130, which is same as a Hydra-Mac 8C, and about half-dozen others (Gehl, and I think it wore green as well)... It originally was powered by an Onan NHCV... opposed twin, with reverse-flow cooling.  The reverse-flow concept was simple... instead of the shrouding and flywheel drawing air in, and forcing it over the heads and cylinders, the flywheel and shrouding pushed it OUT of the shroud, exiting the rear of the machine.  Reverse-flow cooling was fairly normal for Onan's generators- it allowed a gennie to be mounted under the floor of an RV, and direct it's cooling air away in a more-desireable-direction... and at the same time, kept the engine compartment much cooler.

In a skid-steer, that's a great idea... because a skid-steer is like a woodburning stove with a seat and controls in it... the engine heat can bake your beans right quick if it doesn't have serious motivation to make egress.

But because of it's task, and circumstances of job and life, it's actually more like a woodburning stove who's ash-door is welded shut, and it's never been cleaned out.  They wind up being a 350-gallon bucket full of leaves, mud, twigs, beechnuts, acorns, manure, grass clippings, gravel, and of course, tools hiding from extradition.  That makes it a wonderful wintering place for rodentia, particularly the well-armored confines of an air-cooled engine's shrouding.

So... the accumulation means engine tends not to get good airflow... that reverse flow sucks garbage from the floor, right into the shrouding... and then the mice finish it off by plugging up the cylinders, chewing up the wiring and fuel lines.

The Root Of All Evil being Plumbing, there's always hydraulic oil.  Engine oil breather gets plugged, and there's a gooey-greasy crankcase housing... and damned hot exhaust.  As you can imagine, all that heat caused the engine to find it's output limits very early... well before the advertised power curve.  Previous owner of my machine said that when it was brand new, it was adequate, even by today's standards, but by the 5th or 6th season, it had no power for anything but moving snow.  (hmmm... I wonder why)...  When he finally abandoned it, he was in a timber, trying to move a fallen tree from alongside where it'd been parked.  It caught fire a few minutes after starting, so he shut it down, and ran for a fire extinguisher. 

So they catch on fire...  And they burn...  And if you're lucky, in the right place at the right time, and have $300 in hand, you snag one that's had one tire burned off, the exterior well-pigmented, with the seat, all the wiring, battery, and fuel tank cooked, and a few hydraulic hoses melted down, but otherwise, the hydraulic pumps, motors, cylinders, bucket, etc, all still recoverable.  When I got it home, I pulled the wheels, bucket, ROPS and lift arms, yanked out the engine, lifted it up on end, and gave it a good long visit with the pressure washer... there was a 200lb pile of gak in the driveway when I was done.

My solution currently in (slowish) progress, is a 3-cyl 25hp Kubota diesel... just short enough to fit inside the compartment.  The NHCV wasn't a bad idea for it's vintage, but it certainly was not as good as having something taller (like a Wisc V4, or a vertical twin)... but a 1-liter liquid cooled something would have been a much better choice... and that's what I'm doing.  I'm mounting the radiator in such a way that I can switch the direction of the electric cooling fan... so I can either push the heat out, or pull it IN. ;-)

Considering today's options, I personally would NOT use an air-cooled engine in a skid-steer... there's plenty of liquid cooled options nowdays... and the reason is, that regardless cylinder shrouds are entirely too susceptible to the skidder's work environment.  Running liquid cooling means the airflow is over a radiator, which is a much more accessible and controllable surface.  Added bonus, is that the liquid cooled engine is quieter, and more thermally stable... so it doesn't wear as fast.

when you go 'water cooled' PUT ANTIFREEZE IN IT !!!!!

you'd think THAT was 'kinda obvious' but.........someone forgot

NOTME !!

I have a New-Holland 775 that has a Wisconsin V-465-d in it. The 465 has ohv heads on it. Good engines, plenty of power.

I have a NH 778 that has the Ford 172 diesel in it, also a good choice for repower. My third and fav loader is the NH 781 that has a 3-cylinder Deutz in it. That's another option for repower if that is what you need to do. Not sure how big the IH thingy is, but if you have room, you can put any small engine in it , UNLESS it's made for only 1 specific engine. thanks; ac fleet

There's many ways to look at repowering... and no matter how you do it, the result is the same:

If you overpower a hydraulic system, only two things can occur:  the pressure relief valves will open, and the hydraulic fluid will warm up faster.  In neither case will the machine work any harder, because it's limit, is the fluid power transfer capacity which you've exceeded.

Running an engine that is 'too small', will not take full advantage of the hydraulic power available.

So the balance, is finding the result that yields best from both.

In the case of running an engine that is substantially oversized, you have more weight, but can run the engine at a lighter load, which makes for longer life.  Unfortunately, it makes for an extremely tight fit in the engine compartment.

One aspect of the skid-steer that is REALLY mandatory knowledge for a repower:

Balance.  When the bucket is full, 70% of the machine's weight must rest on the FRONT wheels, and when bucket is empty, 70% must ride on the REAR.  This assures that when you turn, it will skid predictably and smoothly, not jump up and down.

Stuffing a small-block V8 seems a little too tight for me... it's just a wee bit longer than an inline four, but no space along the sides to change plugs or other maintenance.  A tiny V6 out of a front-drive car mebbie, but a 90 degree v8 not so much.