The Ford Barn

nkaminar · 05-11-2026, 04:28 PM

Per the Burtz instruction manual:

"Flywheel Attachment Bolts
"Instead of using the original 7/16 UNF x 13/16-inch-long flywheel attachment
bolts, we recommend 7/16 UNF x 1.25-inch-long Grade 8 bolts (McMaster Carr
92620A697) or equivalent with Blue Loctite Threadlocker and a torque of 55 lb-ft."

With the grade 8 bolts and Burtz crankshaft, I elected to use 60 foot-pounds torque. There was not enough room for any lock washers and the heads on the bolts were not drilled for safety wire. I used the Threadlocker but wanted a little more torque as a slight increase in the factor of safety.

The flywheel face runout should be checked after it is installed. Installing the flywheel and checking the face runout is best done with the engine in a engine stand and nose down. The flange on the crankshaft and the the flange on the flywheel should be clean as any dirt or debris can lead to runout. The bolts need to be torqued to make sure that the flywheel and crankshaft are mated securely. The torque on the bolts should be brought up in increments and in a cross pattern. The face runout should be 0.003 or less. If your runout is excessive, try mounting the flywheel 180 degrees from the current position.

05-11-2026, 04:28 PM	#7
nkaminar Senior Member Join Date: Jan 2012 Location: Western North Carolina Posts: 6,855	Re: Bolt Torque? Per the Burtz instruction manual: "Flywheel Attachment Bolts "Instead of using the original 7/16 UNF x 13/16-inch-long flywheel attachment bolts, we recommend 7/16 UNF x 1.25-inch-long Grade 8 bolts (McMaster Carr 92620A697) or equivalent with Blue Loctite Threadlocker and a torque of 55 lb-ft." With the grade 8 bolts and Burtz crankshaft, I elected to use 60 foot-pounds torque. There was not enough room for any lock washers and the heads on the bolts were not drilled for safety wire. I used the Threadlocker but wanted a little more torque as a slight increase in the factor of safety. The flywheel face runout should be checked after it is installed. Installing the flywheel and checking the face runout is best done with the engine in a engine stand and nose down. The flange on the crankshaft and the the flange on the flywheel should be clean as any dirt or debris can lead to runout. The bolts need to be torqued to make sure that the flywheel and crankshaft are mated securely. The torque on the bolts should be brought up in increments and in a cross pattern. The face runout should be 0.003 or less. If your runout is excessive, try mounting the flywheel 180 degrees from the current position. __________________ A is for apple, green as the sky. Step on the gas, for tomorrow I die. Forget the brakes, they really don't work. The clutch always sticks, and starts with a jerk. My car grows red hair, and flies through the air. Driving's a blast, a blast from the past. Last edited by nkaminar; 05-11-2026 at 04:45 PM.