Diamond B Block? Trying to find year.

[stickshift]

I know my 1931 AA truck has a "B" engine. It has a three bolt water pump and I've always thought it was a 1932 engine. I was looking at it today and I noticed a diamond shaped symbol next to the timing gear cover. Does this mean it's a "Diamond Block"? l didn't see any casting dates on the block, but the head has a "C46" casting. Does this mean March 4th 1936? Is there any way to find out the YOM of the block? The serial number has been re-stamped to match my title. I may pull the oil filler tube tomorrow to see if I can see any counter weights down there.

[40-A Twins]

Look for block casting numbers below the gallery cover. Is that a oil filter cannister with bar code visible ? Casting number might be behind that. My block casting number is visible at lower left in this photo

[stickshift]

Originally Posted by 40-A Twins

Look for block casting numbers below the gallery cover. Is that a oil filter cannister with bar code visible ? Casting number might be behind that. My block casting number is visible at lower left in this photo

Yes, That's an oil filter. I may have to remove it to see any block casting number. I tried to use a mirror, but no dice. I'll check tomorrow in the daylight. Thanks for the reply.

[Gary WA]

Originally Posted by stickshift

I know my 1931 AA truck has a "B" engine. It has a three bolt water pump and I've always thought it was a 1932 engine. I was looking at it today and I noticed a diamond shaped symbol next to the timing gear cover. Does this mean it's a "Diamond Block"? l didn't see any casting dates on the block, but the head has a "C46" casting. Does this mean March 4th 1936? Is there any way to find out the YOM of the block? The serial number has been re-stamped to match my title. I may pull the oil filler tube tomorrow to see if I can see any counter weights down there.

Yes, letter is the month-A=january,B=february etc, first number =day,last number is the year in sequence. And the head with matching block number!! Rare..

[rotorwrench]

B engines had the different oil pan that extended under the B style clutch & flywheel housing. The engine numbers were stamped on the flywheel housing and not on the block.

That is a diamond block so it was cast after Ford had stopped casting them. They farmed the block casting out but the assembly of model A & B engines continued till sometime in 1940 or so. They were used as industrial powerplants for water pumps, power generators, air compressors and agricultural equipment by various manufacturers as well as spare parts replacement engine assemblies.

[stickshift]

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Originally Posted by rotorwrench

B engines had the different oil pan that extended under the B style clutch & flywheel housing. The engine numbers were stamped on the flywheel housing and not on the block.

Would the number be where I can see it from under the truck, or would I need to pull up the floorboards? There is a stamped number on the block near the manifold that I inquired about some months ago, but people thought it was a stock number from a rebuild house or the like.

[Keith True]

That won't work for you.The B engine used the B half flywheel housing in the B.s,and when you used a B engine in an A you chop the lower housing off the B pan,and use the A flywheel housing.

[stickshift]

I pulled out the oil breather tube to find if I can see counter weights on the crank. I did see one in front of #1 rod, so I know it's a later B engine. Something strange though, I saw funnel shaped drilled holes on the piston rod caps. I could only see two rods through the hole, but both rod caps (top side) had these drilled holes. They look aftermarket to me. I had a hard time with the iPhone taking pictures, but I think they are visible, Anyone know what these are? Maybe for oiling?

[Synchro909]

Originally Posted by stickshift

I pulled out the oil breather tube to find if I can see counter weights on the crank. I did see one in front of #1 rod, so I know it's a later B engine. Something strange though, I saw funnel shaped drilled holes on the piston rod caps. I could only see two rods through the hole, but both rod caps (top side) had these drilled holes. They look aftermarket to me. I had a hard time with the iPhone taking pictures, but I think they are visible, Anyone know what these are? Maybe for oiling?

When the dipper goes through the oil in the dipper tray, it creates very high pressure for a short time, then there is nothing till the next time around, including the power stroke. The purpose of oil in the engine is to keep the bearings cool. (The fact that it is slippery helps.) To get a cooling effect from the oil, it has to be able to flow through the bearing. Those holes allow the oil from each dip to pass through the bearing, taking heat with it. As the oil exits those holes, it is directed up the bores for another obvious benefit.
As others on this forum who race these engines have said, they run wider clearances - up to 0.025 or more to allow the oil to flow through quickly. I once read "There are plenty of car running around with bearings that are a bit too loose. There are NO cars running around with bearings too tight."

[ursus]

Looks like somebody decided to enlarge the lower rod oil well and feed hole in order to enhance oil flow to the upper half of the bearing. Oops, Synchro909 got here first!