So today I checked to make sure the engine in my newly acquired F2 wasn't locked up, and it certainly wasn't. As far as I can tell it has been sitting for about 43 years as the plates on the truck were dated 1970. So I spun the crank clockwise with a ratchet and 7/8 socket on the crank bolt and it spins freely, very freely, with the plugs installed. Normally this would tell me there is no compression, should I be worried about a cracked block or is this normal behavoir for a 43 year non-running flathead?

 

More or less normal on anything = reserecting the dead. Doesnt take
long for things to stiften up. Get a battery its got to be spinning a little
faster than a ratchet. One by one squirt oil in there- now see what
happens. If no change could be dirty/lazy valves could be entombed
rings all of above. We get involved in this all the time. Another fast
trick we use is to boil CRC or something on a hot plate and fill em up.
All snake oils creep faster if hot. If no avail next we pull the intake
to see if the valves are going up and down. Then even it they do go
up and down, seats could just be dirty. Lastly the heads will come off
for a good visual examination. I dont know your climate, but temp
changes causes cold metal to sweat fact of life. Strong chance it will
run just take your time step by step. I remember being a teen freeing
a stuck 8BA i put that in a water filled 55gal drum and lit a fire under it.
That worked I boiled that thing for two days.

 

I'd get a battery and run a compression test. I'd run both plugs out and plugs in and compare. Make sure the critter has oil pressure before you get too crazy with spinning it.

Edit - oh, free with plugs -installed-. I shoulda read more better. Well, does it have connecting rods? Can you feel resistance at all? I'd still do a compression test.

 

I would do as Big Job suggest if you are hoping to run it without a rebuild. Turning it over bone dry is a bad thing. I would also pull the intake. I just bought an intake gasket for 8 bucks. That will give you a good idea what it going on with the valvetrain, and allow you to lube a lot of things.

 

Thanks for the suggestions. I was going to rebuild it anyway, but I've read that cracked blocks in these things were common. And so I was getting worried that I was about to have to rethink my plans for the project if I was going to have to completely replace the engine.

 

If things go fairly well as far as getting it to develop compression then you might want to fill it up with water and do a cooling system pressure test . You should be able to rent a tester at some place like Auto Zone or whatever depending on where you live.

 

You will have to pull the heads to check for cracks. Not all blocks are cracked......you may get lucky!

 

A cracked block probably wouldn't affect compression in all cylinders.

 

Just bite the bullet and pull the heads if you are planning a rebuild anyway, only way to tell for sure if it is cracked. Mine was a lot like yours, I eventually got it running pretty sweet but the block still turned out to be cracked. Most of the cracks can be repaired so don't lose heart if it is cracked.

 

I had several cracks pinned and 2 sleeves installed . Still not too bad pricewise

 

I know it's a thrill to bring one back from the grave and hear it run, but you can do a lot of damage firing it up with stuck rings, stuck valves, etc.