If there is a crack, then its edges seem to be burned clean, indicating a higher temperature than in the surrounding material has occured there - would make sort of sense. And notice there is carbon build up on top of the piston exactly where the crack supposedly is

 

My 51 flathead 8 had a similar crack. As I was having the motor rebuilt, it was no big deal to have the crack pinned, the cylinder sleeved, and hardened valve seats installed. In your case, if that is a crack, you will unfortunately need to pull the motor.

I never drove mine before the rebuild, so I can't say that your symptoms are consistent with a crack, so take my experience as you can.

John

 

The plot thickens... I have not removed the passenger side head yet, but I looked down the intake and found a nut shell. Also after cleaning the block #7 has a crack at the intake, before cleaning it appeared to be #6. When I have time I will remove the passenger side head and see what fun lies ahead!


Intake of #2

Crack on the intake of #7

 

Is the water jacket as clogged as it appears?

 

No, just looks bad. Stays at 180. I should try to flush it out.

 

What are your plans for the truck? If you want it to be a solid runner, I'd yank the engine and clean it thoroughly, check for wear in the rings/bearings. The clean circumference on the pistons indicates oil coming past the rings. Fresh rings, a hone, and clean cooling systems might put it right. Or you'll find a more serious problem before you spend too much on it.

 

Good point, begin with the end in mind.

I want a truck for light use around town on weekends. I would like it to be as reliable as possible for a 70 year old truck. I do not have the room to take the engine out currently, so I will check the valve clearances, clean the block and heads, put new gaskets and bolts on her. I'll reduce the fuel pressure, and replace the spark plugs. I will be happy if she runs for the next 18 months, and then I should have the space and time for a full rebuild, I believe in the Charlotte area I can find a good shop to do flathead rebuilds.

The oil in the recent pictures is some MMO I squirted around because I have been using Seafoam to get the carbon off.

 

Is the crack where the red arrow is? Did the bolt where the blue arrow is break off?

That's a bad place for a crack, but it may not have gone into the cooling jacket yet.

 

Yes, exactly where the red arrow is pointed. I figured it was a difficult place for a crack, what symptoms would I notice if its into the cooling jacket? Does it make a difference that it is on an intake valve?

The bolt did break off, before I purchased it. Looks like it will be fun to get out as it is almost flush with the block.

 

The hole that bolt is in is not a through-hole, it is part of the exhaust crossover. If you have a welder, I'd recommend welding a nut onto it (see Youtube). See cross-section below.

The crack is in a narrow area, "can" be pinned but is it down into the cylinder? See cross-section below.

 

Ross, you are a wealth of information!

I just checked and it is difficult to see, however it appears the crack is in the cylinder wall about 1/2 inch.

 

That's not good. It can be repaired, cylinder sleeved, as Hulley noted above. You can try using a leak-sealer, it seems to work pretty well for flatheads, if you get the cooling system clean. Some people use black pepper! But I wouldn't put much money into the engine unless it's fixed.

 

Here's a deal on a Gasket Set. You'll have to hurry! - Bob

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