The Ford Barn

A Model Man · 10-08-2018, 04:58 PM

I have about 5000 trouble free miles on a rebuilt standard Model A engine. Recently on tour the engine lost power but continued to run. Compression on warm engine is near 70# on front and rear cylinders but less than 50# on the two in the middle. Removed head, the gasket did not appear to be blown and valves were not stuck and appeared to be operating properly. Could not see any cracks in the head or block. Checked flatness of head and block with a straight edge and feeler guage and they do not appear warped. Filled headless engine block with coolant and there is no leak down of coolant. Installed new copper head gasket and torqued head appropriately to 55 ft/lbs. Rechecked compression and there was no improvement. I am puzzled. Anyone have a similar experience that might give me a next step to pursue?

10-08-2018, 04:58 PM	#1
A Model Man Junior Member Join Date: Jan 2013 Posts: 13	Low compression on cylinder 2 & 3 I have about 5000 trouble free miles on a rebuilt standard Model A engine. Recently on tour the engine lost power but continued to run. Compression on warm engine is near 70# on front and rear cylinders but less than 50# on the two in the middle. Removed head, the gasket did not appear to be blown and valves were not stuck and appeared to be operating properly. Could not see any cracks in the head or block. Checked flatness of head and block with a straight edge and feeler guage and they do not appear warped. Filled headless engine block with coolant and there is no leak down of coolant. Installed new copper head gasket and torqued head appropriately to 55 ft/lbs. Rechecked compression and there was no improvement. I am puzzled. Anyone have a similar experience that might give me a next step to pursue? Last edited by A Model Man; 10-09-2018 at 11:38 AM.