With the engine bottom end open I’m trying to get a measurement of the con-rod bearing clearance but I’ve never worked with TTY fasteners. Instruction says to retighten to specified torque and then remove and analyze the Plastigage but the torque spec for the M20B25 connecting rod to crankshaft bolts is only 14.5 ft-lb but with a 70 degree TTY. I’m concerned if I don’t tighten to more than 14.5 ft-lb I’ll get too large a measurement. On the other hand retorquing a TTY fastener to it’s original tightness seems like a really bad idea.
Measuring clearance w. Plastigage and TTY fastener
Ranger
#2
Do this with used rod bolts, not your new ones. They are good for 2-4 re-uses in this manner. As long as you are careful you will feel the bolt starting to “go” but before it actually snaps. Some bolts will go on the 2nd re-use, some will make it to 4.