The Ford Barn

Bob Bidonde · 11-19-2022, 02:29 PM

At 955 miles on a rebuilt Model "B" engine with a Synder's 6:1 cylinder head, its Best 573 Head Gasket failed between Cylinders 3 & 4 during a parade. At the time, the spark lever was advanced to about 15 degrees (30 degrees BFTDC). Running 87 Octane gasoline with GAV 1/8th turn open, TT10 Motorcraft Spark Plugs & 12V negative ground ignition.

Thinking about the cause of failure, I suspect: (1) Lugging the engine with too much spark advance during the parade; (2) Generally driving with too much spark advance (20 - 25 degrees ignition); (3) Loosening Cylinder Head Nut 8 to remove the distributor and not re-torque enough. The engine did not overheat since its rebuilding.

Replaced the failed gasket with a Best 509 Kevlar Gasket without sealant. Initially torqued head to 55 lbs-ft in steps of 30, 45 and 55. Overnight the gasket compressed without any engine run, so I re-torqued the head to 55 lbs-ft.

Timed the ignition at TDC #1 with the spark lever down 5 notches to regain full travel of the lever with the 6:1 head. With water as a coolant, I ran the car 13 miles, drained the coolant to add anti-freeze and re-torqued the head while it was hot to 60 lbs-ft. No leaks while engine is running.

More to follow as I put more miles on the car.

11-19-2022, 02:29 PM	#1
Bob Bidonde Senior Member Join Date: May 2010 Location: Long Island, NY Posts: 4,114	Head Gasket Failure & Replacement Saga At 955 miles on a rebuilt Model "B" engine with a Synder's 6:1 cylinder head, its Best 573 Head Gasket failed between Cylinders 3 & 4 during a parade. At the time, the spark lever was advanced to about 15 degrees (30 degrees BFTDC). Running 87 Octane gasoline with GAV 1/8th turn open, TT10 Motorcraft Spark Plugs & 12V negative ground ignition. Thinking about the cause of failure, I suspect: (1) Lugging the engine with too much spark advance during the parade; (2) Generally driving with too much spark advance (20 - 25 degrees ignition); (3) Loosening Cylinder Head Nut 8 to remove the distributor and not re-torque enough. The engine did not overheat since its rebuilding. Replaced the failed gasket with a Best 509 Kevlar Gasket without sealant. Initially torqued head to 55 lbs-ft in steps of 30, 45 and 55. Overnight the gasket compressed without any engine run, so I re-torqued the head to 55 lbs-ft. Timed the ignition at TDC #1 with the spark lever down 5 notches to regain full travel of the lever with the 6:1 head. With water as a coolant, I ran the car 13 miles, drained the coolant to add anti-freeze and re-torqued the head while it was hot to 60 lbs-ft. No leaks while engine is running. More to follow as I put more miles on the car. __________________ Bob Bidonde