I tore down a '54 235 truck engine today and found a couple of mysteries. #1. The main bearing cap bolts had heavy split lock washes under them? Do they belong there? #2. The oddball head bolt with the groove in the head and the hole drilled in the end of it was on this engine. I have included pics of the block and head #s indicating that they are '54 parts.
A split lock washer under a main bearing bolt is a really bad idea, as they usually spread out at the split and let the bolt lose its torque. If a washer is used at all, it would need to be a hardened Grade 8 SAE flat washer, never a lock washer of any kind. The head bolt with the slot across the top is one with a 1/16" hole drilled through the center, and another hole at right angles intersecting it above the threaded part of the bolt. It's there to adapt the oil circuit to the rocker arms on certain cylinder head/rocker arm combinations. That bolt is supposed to be located at the center of the head on the passenger's side, and if there's a piece of 3/16" tubing from the pushrod valley to the oil connector in the center of the rocket arms, that bolt isn't needed. Jerry
The murder victim was drowned in a bathtub full of Rice Krispies and milk. The coroner blamed the crime on a cereal killer!
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
What the presence of those washers and bolt tell you is that someone who may or may not have known what they were doing was into that motor at one time or another and you should pay attention to every detail as who knows what other "tricks" were used on this motor.
28 Years of Daily Driving but now on hiatus. With a '61 261, 848 head, Rochester Monojet carb, SM420 4-speed, 4.10 rear, dual reservoir MC, Bendix up front, 235/85R16 tires, 12-volt w/alternator, electric wipers and a modern radio in the glove box.
The major downside of the split washer that I recently encountered, also on a 54 235, was that when when loosening the bolt to check bearing clearances, the split washer would rotate some and cut chips off the bearing cap. Of course they fall into the engine and then you get to re-clean everything.
Split lock washers have long been considered marginal at best for securing a robust threaded joint. When a split lockwasher is fully compressed flat it has no retaining "bite" at the split and actually becomes a flat washer with a crack. The tensile spring force created by the compression of the washer contributes only around 10% of the torque preload. The rest is covered by bolt stretch. For the washer to bite and provide a lock the bolt will need to back off a bit but then the clamp load is lessened and you're joint has failed. The best lockwasher for high preloads is a conical washer with serrated faces. For the most part though using the tensile bolt stretch to clamp the load is the best approach and is the norm.