The Stovebolt Site Forums The Shop Area Engine Shop Looking for "advice" on an engine core for rebuilding

This isn't really a "Parts Wanted" post. Mostly looking for advice on locating a good core for rebuilding. Seems like getting one of these old engines line bored is a problem, at least in my area. Either shops don't have the expertise and equipment, or they just don't have any interest in a job like this. So I'm thinking finding a new block is the simplest solution to my problem. The engine is for a '54 truck but the current engine is a '55 passenger car block. From what I've learned the best choice would be a '56-'62 block since the bearings are available, but a '54 or '55 would be OK since slots for the tangs can be cut without too much difficulty.

Will be heading to Fall Carlisle next week and was wondering what I should really be looking for in a core other than it not being locked up. Thanks in advance!

Tom

The "best fit" situation would be a 1954-early 55 235 block, the one with the high mount water pump location. That puts the fan in the right position relative to the radiator. Yes, the slots for the locator tangs on the 56-62 main bearings would need to be cut, but any machine shop that doesn't want to do that doesn't need your business anyway.

Here's another option- - - - -leave the original main bearings in place, line bore (or hone) them to fit the OD of a set of Chevy LS main bearing shells, and grind all four crankshaft journals to the same size as an LS crankshaft. Crankshaft thrust is still controlled by the original #3 main bearing flanges. Main bearings for a Chevy small block 400 can also be used that way. Here's you tube video that explains the process better than me wasting a few billion electrons on text:

Chevrolet Straight Six is a One-of-a-Kind Creation!


Jerry

Ok, so the truck was a running, driving vehicle whan I started all this. The problem arose when I tried to replace the very leaky rear main seal. I did post early on that the block was a late '55 block, casting #2836233 with a casting date of H55 with a '55 vin stamp. Was told that the block was a low water pump block.

Everything fit fine and cooling on the hottest days was not a problem. So unless I'm missing something, NOT finding a high water pump and using a low water pump block shouldn't be a problem, right? Either way, does anyone have any measurements that would confirm that what I have is a high or low water pump engine? Thanks!

"High" water pump engines have a pump with a cast iron pulley that's pressed onto the pump shaft, and the pump bolts on almost touching the thermostat housing. "Low" pumps have an extended shaft, and a stamped sheet metal pulley that bolts onto the pump hub. If you're looking at a bare block, the high pump blocks have two holes in the front of the block near the top for coolant to flow from the pump to the block. Later models have a big single hole (about 3" in diameter) and the pump impeller goes back into the block. High pump engines have the impeller inside the pump housing, with a sheet metal cover over the impeller. Pre-68 Dave's adapter plate replaces the back plate on the 216 style pump and allows the high pump to be installed on a low pump block. It requires two holes to be drilled and tapped into the front of the block, but it's an easy fix.
Jerry

I would think the casting/date code tells us what we need to know. a '55 date code would indicate a low water pump.... unless ... the casting code indicates it was cast in a '54 mold. If my '59 261 is any guide, the later crate engines made for the '54 and earlier trucks (i.e., "High water pump" engines) would have the '54 casting code but with the later date codes. Meaning that if both your casting and date codes indicate a '55 or newer 235 or 261, then you would have the low water pump.

I could be wrong about this, but I doubt it. I'm never wrong. A touch shy of being right sometimes, but never wrong.

50+ years ago, when Mary and I were dating, I said "Once- - - - -long ago- - - -I thought I was wrong- - - -but I was mistaken!" I get reminded of that little comment- - - -on a regular basis! LOL!
Jerry

From time to time I err purposefully in order to give my wife something cling to so that she doesn't feel as bad about her being wrong most of the time.
I have always been known to be a giver...

Curious about the main bearing replacements. So the old, original bearings were left in place, and the block was line bored through them so LS mains would then fit? I wonder if the LS main bearings had a tang on their OD to prevent spinning. Also an interesting idea about the rear main seal. What ford engine was the seal from?

The problem with using LS main bearings inside the original bearing shells is that the rear main bearing on the stovebolt engine appears to be too big to position the LS bearing accurately after the line bore job. Using small block 400 main bearings would seem to solve that problem, as they have a slightly larger OD. Either way, the stovebolt crankshaft is reground to the same size, front to rear, to fit the new bearings. Slots for the locator tabs are filed into the old bearings, or added with a Dremel tool. The only thing a tab actually does is locate the bearing correctly front to rear- - - -the "crush" built into the bearing diameter is what prevents spinning. I also like to attach the stovebolt main bearing shells to the block and main cap with flat head brass machine screws and LocTite, to make sure they don't get dislodged while fitting the new main bearings. Do that before the line bore/hone job.

I've been using a different full circle rear seal, one that's the right size to fit the stovebolt seal surface, (3.875" OD) so no alteration of the crankshaft is required. That seal is a Timken #417210 or the equivalent size in National, BCA, etc. The dimensions are 3 7/8" ID and 4 3/4" OD, 3/8" thick. If the crankshaft seal surface is worn or pitted, a SKF#99387 "speedy sleeve" is used to give a durable stainless steel surface for the seal lip to ride on. The lip seal can handle a +/- .015" diameter difference and still seal effectively. I bore the back of the block with an adapter plate I made to mount my Van Norman cylinder boring bar to the back of the engine block, but the same thing can be done in a Bridgeport mill with a long, tedious setup procedure. My fixture bolts onto the block in about 15 minutes.
Jerry

IF it were me and i was more less starting from scratch, i would look for a 261 to get the most bang for my money.. Jay D.

261 blocks are scarce and E$$$$PENSIVE. A 235 can become a 256 cubic inch with the right bore/stroke combination, using big block Chevy V8 connecting rods and pistons for a Japanese Diesel engine, or a Ford 223 six piston. That setup uses a 4 1/8" stroke, and makes more torque than a regular 261 due to the longer stroke. Increasing the stroke to 4 1/4" gives 263 cubic inches with the same piston and a different length connecting rod.
Jerry