The Stovebolt Site Forums The Shop Area Engine Shop a couple of '54 235 mysteries

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

Split washers were used on 216’s and early 235’s. If you try to leave them out, the bolts will likely bottom out before they tighten against the cap. Thats been my experience.

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.

Nothing seems amiss here. Split washers were used from the factory up until 1954 (see parts book listings), and 1955 1st truck.

Dave,

Did the use of split washers continue to the '61 261? Mine had front cap bolts with no washers but was that something the rebuilder did on his own?

261’s follow a slightly different time line for changes, but I am sure they dropped the split washers close to 1955 1st series.

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.

No problem there. The block is a boat anchor with a crack in #4 cylinder from the the top of the deck, all the way to the bottom of the ocean, where this block will soon reside, metaphorically speaking of course. I did salvage many nice parts off of it for another 235 I plan on rebuilding one day.

I checked the rocker arms for any offset from center of the oil grooves, and found the grooves to be centered. The block has the 3/16" oil line under the side cover, so who knows why "Wally" put that specialty bolt in there, or where he was even able to find one.