Fired my flathead today for the first time!!!

[flthd31]

Well, theres more to the story. Day after I fired it for the first time I lit it off again. It spit a shot of water out the passanger side header. Pulled the plugs on that side, shot water out the number 2 cylinder. Hmmmm....pulled the head and found a crack in the Edmunds head:

I had the heads milled and the cracks were not there. I torqued them to 30, then 50 in the right sequence so I do not know what caused the crack. My Dad had a magentis dial indicator and we ran the numbers on all 8 clinders to measure how far up they came above the deck...making sure the rod did not bend. It was fine

This event brings back some bad memories.
Years ago I had the similar thing happen to me. We did all the tests you did and determined that "all was fine" just as you did.
That engine ran perfectly for 6 months and then one day while cursing down the road at a leisurely 55 mpg, all hell broke loose. By the time I coasted to a stop, that engine was total scrap except for the 4" forged merc crank and 3 lifters. A couple of rod pieces were actually laying in the frame rail.
When I tore it down, you could see from the rod bearing wear that it had been wobbling slightly.
My 2 cents of advice would be to replace that rod. Sure wish I had!

 

[Chris]

This event brings back some bad memories.
Years ago I had the similar thing happen to me. We did all the tests you did and determined that "all was fine" just as you did.
That engine ran perfectly for 6 months and then one day while cursing down the road at a leisurely 55 mpg, all hell broke loose. By the time I coasted to a stop, that engine was total scrap except for the 4" forged merc crank and 3 lifters. A couple of rod pieces were actually laying in the frame rail.
When I tore it down, you could see from the rod bearing wear that it had been wobbling slightly.
My 2 cents of advice would be to replace that rod. Sure wish I had!

You had a leaky head and had water some into the combustion chamber? You ran a dial indicator on it and the piston came up to the same specs as the others? I don't see how a rod can bend and still be the same height. Did you check yours for plat up and down, side to side? We did on mine, it was nice and tight up and down, and had slight play side to side like it should. I'm not arguing, just trying to understand what happened in your engine.

 

[flthd31]

You had a leaky head and had water some into the combustion chamber? You ran a dial indicator on it and the piston came up to the same specs as the others? I don't see how a rod can bend and still be the same height. Did you check yours for plat up and down, side to side? We did on mine, it was nice and tight up and down, and had slight play side to side like it should. I'm not arguing, just trying to understand what happened in your engine.

The car was a 47 coupe with a 49 Merc that was just rebuild. It was bored .125 over, Isky Max1 cam. Entire reciprocating assy was balanced with flywheel and pressure plate. Ran smooth as silk and tacked up to 5000 very quickly. 2 97's on Elelbrock intake and Edelbrock heads. It had about 500 miles on it.
Back then, big bore head gaskets were impossible to find and I was using some graphite composites that turned out to be junk. The water seeped in after sitting for a few days. When I started it on a Sat morning, I had the exact experience you had with water flowing out of the header. I pulled the head and could see where the gasket failed.
The head was fine with no damage. I have a set of hydro test plates (head and water pump), so we put them on to make sure the block wasn't cracked...tested ok.
Next we checked the rise of the piston with a dial indicator and it looked good. In hind sight, we think the rod may have been twisted slightly.
All I can say is that those old Fords rods are tough, but they can't compress water...something has to give. Maybe that's what cracked your head?
If i could go back in time, I would have torn it down, not that big of a deal compared to a total loss of a new engine.