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Ive read a few threads about cracked blocks, what causes it and how do you tell if a block is cracked? Does the tractor run rough and smoke?
 

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The most common cause is freezing coolant. This usually cracks the outside where it is visible but it can also crack inside. Just follow the trail of coolant. Internally engines can develop stress or heat cracks as well. They are normally found in the head.

Cracks in the head can lead to loss of compression and water in the cylinder, too much pressure in the rad. They could make it run rough and smoke, especially on start-up, so could a bad head gasket.You are looking for white smoke. That's coolant. If the smoke has a bluish tint to it, that's oil smoke. It's also possible that the valves are carboned up and not working properly.
 

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My Orange Jane Deere
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A rod going east or west instead of north and south. :sidelaugh
 

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The most common cause is freezing coolant. This usually cracks the outside where it is visible but it can also crack inside. Just follow the trail of coolant. Internally engines can develop stress or heat cracks as well. They are normally found in the head.

Cracks in the head can lead to loss of compression and water in the cylinder, too much pressure in the rad. They could make it run rough and smoke, especially on start-up, so could a bad head gasket.You are looking for white smoke. That's coolant. If the smoke has a bluish tint to it, that's oil smoke. It's also possible that the valves are carboned up and not working properly.
The above is spot on! Good info.
To add alittle more info to the above. The freezing coolant is more than likely straight water or very diluted water/antifreeze mixture.
In this case there will be rust and corrosion in the block, head, radiator, hoses etc. There may be more problems than just a cracked block in this case.
Even tho most engines have freezeout plugs, they can get rusted in and not give.
Generally a cracked block will tell on itself as it won't be running right, if at all.

Another source of cracked blocks in old tractors where the engine constitutes part of the framing is from overloading FEL's. That stress has to go somewhere and generally it's the block.
Driveing these old machines as if they're ATV's can do it too.
 

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"Freeze-out" plugs are a misnomer. They are core plugs used to cover the openings for the sand cores when the block is cast. In a worst case scenario, they may function as freeze plugs, but that's not their intention. Some heavy duty and racing engines use screw type plugs for that purpose, no way they're moving when frozen.
 

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Ive read a few threads about cracked blocks, what causes it and how do you tell if a block is cracked? Does the tractor run rough and smoke?
You don't mention if your dealing with an air or liquid cooled engine but, as mentioned, heat will do it to either. Excessive vibration from out of balance attachments can cause cracks around manifolds, motor mounts and other attachment points. Adding excessive amounts of weight to exhaust ports and improper torquing of bolts can also cause problems.

For liquid cooled engines probably the major cause of cracking has been covered, this is freezing of the coolant.

Some blocks crack for no apparent reason due to structural flaws or poor design. An example of this would be the cracks that would show up between the third and fourth cylinders of some series of the old Chrysler Corporation six cylinder industrial engines.

Liquid cooled engines will usually show low liquid in the radiator, white smoke on startup if the coolant is getting in a cylinder, overheating, water in the oil and/or visible coolant on the outside of the engine. Rough running and loss of power also often are noticed.

Air cooled engines seem to be more tolerant of cracks to a point. Usually loss of power or rough running have been what I've noticed first. Overheating can also occur.

If sufficiently severe the problem can cause an engine to refuse to start or even crank over.

Mike
 

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Discussion Starter #9
Thanks guys, that was alot of good info. i dont have a cracked block i was just interested in the tell tale signs.
 

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The above is spot on! Good info.
To add alittle more info to the above. The freezing coolant is more than likely straight water or very diluted water/antifreeze mixture.
In this case there will be rust and corrosion in the block, head, radiator, hoses etc. There may be more problems than just a cracked block in this case.
Even tho most engines have freezeout plugs, they can get rusted in and not give.
Generally a cracked block will tell on itself as it won't be running right, if at all.

Another source of cracked blocks in old tractors where the engine constitutes part of the framing is from overloading FEL's. That stress has to go somewhere and generally it's the block.
Driveing these old machines as if they're ATV's can do it too.
It can drive though if it does have a cracked block though can't it..cause my buddy thinks he may be dealin with one himself and I told him to look at this conversation as it might help him figure it out but he said his is till running.
 

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my dad was using his Ford 2n for something it was not meant to be.... long sotry short his engine block shattered into 6 or 8 bits & pieces. Oddly enough he's an accomplished cast-iron welder and managed to put it back to gether. It even runs & works yet. He bought a small dozer to do the heavy work and keeps the 2N for much much ligher work now. The block on it looks like frankenstine, but it keeps goin.
 
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