Cracked Block

TobbyT

TobbyT

Member
Well it looks like my new 1950 F-3 has a cracked block. Has anyone every used any type of Cracked Block repair stuff I see advertised that comes in a bottle on a flathead V8?
The reason I ask, this is a new truck and I’ve never driven it. I have no idea what condition the brakes, transmission or rear end are in.
 
What observation leads you to the cracked block conclusion? If it runs, I would try Bars before any other fix.
 
I must ask, how did you determine the block is cracked ? Water in the oil ? Could it be a faulty head gasket ?
 
You will not get any help unless you describe IN DETAIL why you think your block is cracked. I assume it is the original V8 ??? John
 
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You guys are good !! Ok here are the details. Got the truck home and found no compression in several cylinders. I was told the motor was running when it was parked 18 months ago. Pulled the heads and found some stuck valves in #2, #3 & #7 Cylinders. Also found water in #3 cylinder. Visually inspected heads, cylinders and gaskets and they all looked good. Unstuck valves and replaced the heads with new gaskets. Rechecked compression and compression was better. I thought I would see if I could get the motor to fire before connecting all the hoses and refilling with water. I got it started and she ran rough. I only ran for about 30 seconds. Reattached hoses and filled with water. Tried to crank and noticed water being pushed out of radiator as the motor rotated. Removed spark plugs from passenger side and turned over the motor. Number 3 cylinder is pumping out water. Remover the head on passenger side and inspected head and new gasket again. All looks good. Checked #3 Cylinder valves and it looks like I have a crack block around the intake valve. I plan to pull the intake and remove the valves in #2 & #3 to get a better look. There is no water in the oil.
 
TobbyT said:
You guys are good !! Ok here are the details. Got the truck home and found no compression in several cylinders. I was told the motor was running when it was parked 18 months ago. Pulled the heads and found some stuck valves in #2, #3 & #7 Cylinders. Also found water in #3 cylinder. Visually inspected heads, cylinders and gaskets and they all looked good. Unstuck valves and replaced the heads with new gaskets. Rechecked compression and compression was better. I thought I would see if I could get the motor to fire before connecting all the hoses and refilling with water. I got it started and she ran rough. I only ran for about 30 seconds. Reattached hoses and filled with water. Tried to crank and noticed water being pushed out of radiator as the motor rotated. Removed spark plugs from passenger side and turned over the motor. Number 3 cylinder is pumping out water. Remover the head on passenger side and inspected head and new gasket again. All looks good. Checked #3 Cylinder valves and it looks like I have a crack block around the intake valve. I plan to pull the intake and remove the valves in #2 & #3 to get a better look. There is no water in the oil.
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8ba has right and left head gaskets.
 
welcome to the 'Barn...lol...yeah, there are a buncha guys with lots of experience with flatheads....and hopefully your problem can be found and fixed....Mike
 
Water being pushed out could be a blocked radiator. Cracks around valve seat aren't always a deal breaker. You need to clean that radiator before you do anything.

Don't re-use head gaskets. If there is no water in the oil put it together, get that radiator cleaned out and try it again. Go through the distributor and time it. Go through the carb and use a cheater fuel ine until you clean out the gas tank.

Once it is running we can talk you through diagnostics.
 
Thanks for all the advice. I need all the help I can get. I will check the radiator. It will need to be removed because it has a few leaks. Dad always said that the biggest problem with the old flatheads was the 4lb radiator cap. If the slightest thing was wrong with the radiator, the 2 water pumps would build up pressure at the top of the radiator and push the water out the overflow.

There is a lot of water being pushed out the #3 spark plug hole. My #3 cylinder would make a good fire extinguisher if the battery ever caught fire !!
 
I can't say that a motor won't crack in an intake valve pocket but it is less common. I can say that they generally crack in the exhaust valve pockets due to the heat there. Check your cylinder heads for cracks or pin holes too. The heads can warp and cause sealing problems with the head gasket so find yourself a good straight edge & use the feeler gauges to check. Check the deck too.
 
rotorwrench said:
I can't say that a motor won't crack in an intake valve pocket but it is less common. I can say that they generally crack in the exhaust valve pockets due to the heat there. Check your cylinder heads for cracks or pin holes too. The heads can warp and cause sealing problems with the head gasket so find yourself a good straight edge & use the feeler gauges to check. Check the deck too.
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I already had the head off the motor so today I pulled the intake and removed the #3 valves. I can’t see or feel a crack. I pulled the #2 valves and still no crack. I think I’ll take the head to the machine shop and let them check it out. I hope they find something.
 
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