Diamond B question.

hardtimes

hardtimes

Well-known member
I just acquired a 1937 diamond B block.
Haven’t looked at it ( disassembled) yet.
Have any of you owned and/or rebuilt such block ?
Wanting any info as to whether this B is same as ‘32 B or any differences ?
Thanks for any information !
 
I have a Model "B" Diamond Block in each of my Model A's. They are aftermarket engines, and assemble the same as the production engines. The only advantage I see for a Diamond Block is they likely have all of the product improvements / tweaks to the tooling Ford made. Both of my Model "B" Diamond Blocks came with counterbalanced crankshafts.
 
I have a diamond A block and the only differences I found were a B cam, hardened exhaust seats and the diamond.
 
There were several foundries in the early 1930s that used a diamond for a casting mark but I haven't yet found any information about who that subcontractor was. Model A and B engines were produced for a long time after the model A, B, and model 40 production period ended. The blocks were cast by an outside contractor but Ford did have an assembly line for replacement engines and industrial engines.

Model B engines had some thin spots in the cooling passages of the deck area that had more instances of cracking than the basic model A block. It's harder to find good original Model B blocks whether diamond block or Ford cast units than it is for model A blocks. The model B certainly had some improvements for performance but I don't know how much better they were.
 
Picked up a February 23rd 1937 block yesterday,crack free.Deck and upper block casting can be an issue,have a May '36 block that cracked from exhaust valve to cylinder in 2 & 3,a master tool maker owned it before me,he pinned the cracks,installed seats ,sleeved #2 and decked it.Have another '36,the deck is perfect.Got all three with counterbalanced crankshafts for less than a scat A counterbalanced crank..
 
I believe all diamond blocks came with hard exhaust seats. I do know all diamond B blocks are not the same. I have one that has very big valves, with very big ports, all aftermarket because it was raced. I have another that has stock exhaust valves and mildly ported exhaust ports. A few years ago while freshening up that engine using only a sanding drum to clean the ports, I noticed a dark spot on #3 exhaust port. Probing it with an awl, it went right into water.
 
Ford started using hardened seats in 1935 with the V8 engines so it would make sense that this would follow in sub contracted engines as well.
 
I have a 8/11/35 (that's November 8th to you guys) diamond block in my Tudor. It was rebuilt in Kelowna, BC Canada with inserted bearings. It's not my most powerful engine but it is the smoothest running so I stuck with solid engine mounts. I think it is that which makes this car soooo nice to drive.
 
I have a Diamond "B" block, no cracks in the deck, counterweighted crank. Putting it together for my 31 Vickey.

Have a counterweighted crank engine in my Tudor, definitely smoother than a stock A or non-counterweighted "B" engine.

Chris W.
 
The '37 block was bored to 4.060..be a candidate for a Serr head once I hit the lotto..going to build a modified flathead touring engine out of one of the other two,the repaired block is in first position at the moment,new babbited mains and first rate repairs,its basically ready to assemble.I figure cracks relieve stress,repaired properly its as good as new..pressurized mains, a large journal counterweight crank with the last engineering revisions? I'm okay with that.
 
Hey Jim B,
IMO and experience, guys should pay attention to what you stated here.
I had same experience with a hot freshly rebuilt B !
If I remember correctly, YOU gave me some advice on possible remedies... one of which worked ! This was a ‘32 B. I’m betting this ‘37 diamond B has better metal. I’m a little smarter regarding proper blk evaluation from that experience.
 
It all depends on what your goals are. I understand finding the last inch in racing, its the difference. Street and touring not so much, my goal is to hold 2200 rpm for a few hours on a freeway. For me, hogging out ports and big valves might be something to talk about but aren't necessary. When buying used engines I set a 'throw away' price, based on the particular engines desirability and my gut accepting the fact i may have to walk away from it.
 
It all depends on what your goals are. I understand finding the last inch in racing, its the difference. Street and touring not so much, my goal is to hold 2200 rpm for a few hours on a freeway. For me, hogging out ports and big valves might be something to talk about but aren't necessary. When buying used engines I set a 'throw away' price, based on the particular engines desirability and my gut accepting the fact i may have to walk away from it.
 
jim brierley said:
i believe all diamond blocks came with hard exhaust seats. I do know all diamond b blocks are not the same. I have one that has very big valves, with very big ports, all aftermarket because it was raced. I have another that has stock exhaust valves and mildly ported exhaust ports. A few years ago while freshening up that engine using only a sanding drum to clean the ports, i noticed a dark spot on #3 exhaust port. Probing it with an awl, it went right into water.
Click to expand...

ouch!
 
rotorwrench said:
There were several foundries in the early 1930s that used a diamond for a casting mark but I haven't yet found any information about who that subcontractor was. Model A and B engines were produced for a long time after the model A, B, and model 40 production period ended. The blocks were cast by an outside contractor but Ford did have an assembly line for replacement engines and industrial engines.

Model B engines had some thin spots in the cooling passages of the deck area that had more instances of cracking than the basic model A block. It's harder to find good original Model B blocks whether diamond block or Ford cast units than it is for model A blocks. The model B certainly had some improvements for performance but I don't know how much better they were.
Click to expand...

I agree , but add that if I locate a 'good' B or A block, the oil provisions / improvements that Ford developed for the B is the decider , for me.
 
Oiling and the bigger main and rod bearings in the "B" makes for a much better engine. The Factory counterbalanced crank is the final improvement that makes a very good engine for these old cars.

A well put together "A" engine will run fine but you are still dealing with the smaller main and rod bearings.

Again, this is just my opinion,

Chris W.
 
I seem to have Diamond engines in the whole fleet now - three B's and one A. The one I've just rebuilt for the Coupe had a crack around a tappet boss which I had laser welded. No difference between a stock B engine and a diamond other than the valve seat inserts, but they do seem to have thicker decks.

Oddball on the bench at the moment is a 'GS' block. Only seen a couple. B block with a 'GS' cast under the number pad. Really thick deck and generally feels heavier. Not weighed it though.
 
You must log in or register to reply here.
Back
Top