The Ford Barn

Bud · 03-05-2017, 08:21 PM

I am working on putting my B engine back together. The block had cracks from the valve seat area to the water jacket. I had these stitched. The engine shop lightly honed the bores to clean them up. Everything has been cleaned up. I am measuring the crank and connection journals, plus have plastigaged all the bearings. I don't have the measurements in front of me, but basically the mains are .0020" and the connections are .0010" diametral clearance. Once I had the crank installed with no pistons it was easy to turn but I would not say it would spin by hand. This engine had about a 1000 miles on it after a rebuild before the cracks became apparent. I have installed a bronze timing gear, a Stipe cam, set all the valves, and cleaned up and installed the pistons.
I did have to install a new connection on #3 because I messed up the thrust surface of the connection babbit--my installation mistake. I re-plastigaged that connection and it had .0010" clearance. Since I have installed that piston assembly and #4 piston assembly, the crank has been very difficult to turn. I plan to go in and investigate #3, but I thought I would ask what I should expect regarding turning effort with all four pistons installed plus cam with valves and springs? The cylinder head is not installed. I think I have in excess of 150 ft-lbs of breakaway torque. That is with everything very well oiled. I would like some idea of what torque I should expect at the stage where it is just the crank, just the crank and cam, and what torque I should pick up by adding each piston assembly. Thanks in advance for any information you are willing to share.

03-05-2017, 08:21 PM	#1
Bud Senior Member Join Date: May 2010 Location: Ohio Posts: 851	Turning Torque of B Engine I am working on putting my B engine back together. The block had cracks from the valve seat area to the water jacket. I had these stitched. The engine shop lightly honed the bores to clean them up. Everything has been cleaned up. I am measuring the crank and connection journals, plus have plastigaged all the bearings. I don't have the measurements in front of me, but basically the mains are .0020" and the connections are .0010" diametral clearance. Once I had the crank installed with no pistons it was easy to turn but I would not say it would spin by hand. This engine had about a 1000 miles on it after a rebuild before the cracks became apparent. I have installed a bronze timing gear, a Stipe cam, set all the valves, and cleaned up and installed the pistons. I did have to install a new connection on #3 because I messed up the thrust surface of the connection babbit--my installation mistake. I re-plastigaged that connection and it had .0010" clearance. Since I have installed that piston assembly and #4 piston assembly, the crank has been very difficult to turn. I plan to go in and investigate #3, but I thought I would ask what I should expect regarding turning effort with all four pistons installed plus cam with valves and springs? The cylinder head is not installed. I think I have in excess of 150 ft-lbs of breakaway torque. That is with everything very well oiled. I would like some idea of what torque I should expect at the stage where it is just the crank, just the crank and cam, and what torque I should pick up by adding each piston assembly. Thanks in advance for any information you are willing to share.