Go Back   The Ford Barn > General Discussion > Model A (1928-31)

Sponsored Links (Register now to hide all advertisements)

Reply
 
Thread Tools Display Modes
Old 12-06-2020, 01:24 AM   #1
hardtimes
Senior Member
 
hardtimes's Avatar
 
Join Date: May 2010
Location: South California
Posts: 6,188
Default Diamond B question.

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 !
hardtimes is offline   Reply With Quote
Old 12-06-2020, 01:36 AM   #2
J Franklin
Senior Member
 
J Franklin's Avatar
 
Join Date: May 2010
Location: Oregon
Posts: 5,947
Default Re: Diamond B question.

Same specs, but maybe later better casting. A lot were used in farm machinery.
J Franklin is offline   Reply With Quote
Sponsored Links (Register now to hide all advertisements)
Old 12-06-2020, 09:33 AM   #3
Bob Bidonde
Senior Member
 
Bob Bidonde's Avatar
 
Join Date: May 2010
Location: Long Island, NY
Posts: 3,432
Default Re: Diamond B question.

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.
__________________
Bob Bidonde
Bob Bidonde is offline   Reply With Quote
Old 12-06-2020, 09:52 AM   #4
mike657894
Senior Member
 
mike657894's Avatar
 
Join Date: Oct 2015
Location: Bay City Michigan
Posts: 1,050
Default Re: Diamond B question.

I have a diamond A block and the only differences I found were a B cam, hardened exhaust seats and the diamond.
mike657894 is offline   Reply With Quote
Old 12-06-2020, 10:37 AM   #5
rotorwrench
Senior Member
 
rotorwrench's Avatar
 
Join Date: Jun 2010
Location: San Antonio, Texas
Posts: 16,371
Default Re: Diamond B question.

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.
rotorwrench is offline   Reply With Quote
Old 12-06-2020, 11:45 AM   #6
Jack Shaft
BANNED
 
Join Date: Dec 2019
Posts: 1,196
Default Re: Diamond B question.

Sponsored Links (Register now to hide all advertisements)
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..
Jack Shaft is offline   Reply With Quote
Old 12-07-2020, 12:13 PM   #7
Jim Brierley
Senior Member
 
Join Date: Jun 2010
Location: Temecula, CA
Posts: 4,066
Default Re: Diamond B question.

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.
Jim Brierley is offline   Reply With Quote
Old 12-07-2020, 03:08 PM   #8
rotorwrench
Senior Member
 
rotorwrench's Avatar
 
Join Date: Jun 2010
Location: San Antonio, Texas
Posts: 16,371
Default Re: Diamond B question.

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.
rotorwrench is offline   Reply With Quote
Old 12-07-2020, 03:17 PM   #9
Synchro909
Senior Member
 
Synchro909's Avatar
 
Join Date: Jun 2014
Location: Melbourne, Australia
Posts: 7,472
Default Re: Diamond B question.

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'm part of the only ever generation with an analogue childhood and a digital adulthood.
Synchro909 is offline   Reply With Quote
Old 12-07-2020, 07:33 PM   #10
CWPASADENA
Senior Member
 
CWPASADENA's Avatar
 
Join Date: May 2010
Location: PASADENA, CA
Posts: 1,882
Default Re: Diamond B question.

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.
CWPASADENA is offline   Reply With Quote
Old 12-07-2020, 08:25 PM   #11
Jack Shaft
BANNED
 
Join Date: Dec 2019
Posts: 1,196
Default Re: Diamond B question.

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.
Jack Shaft is offline   Reply With Quote
Old 12-08-2020, 01:39 AM   #12
hardtimes
Senior Member
 
hardtimes's Avatar
 
Join Date: May 2010
Location: South California
Posts: 6,188
Default Re: Diamond B question.

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.
hardtimes is offline   Reply With Quote
Old 12-08-2020, 09:17 AM   #13
Jack Shaft
BANNED
 
Join Date: Dec 2019
Posts: 1,196
Default Re: Diamond B question.

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.
Jack Shaft is offline   Reply With Quote
Old 12-08-2020, 09:44 AM   #14
Jack Shaft
BANNED
 
Join Date: Dec 2019
Posts: 1,196
Default Re: Diamond B question.

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.
Jack Shaft is offline   Reply With Quote
Old 12-08-2020, 03:30 PM   #15
Dave in MN
Senior Member
 
Dave in MN's Avatar
 
Join Date: May 2010
Location: Jordan, MN
Posts: 1,410
Default Re: Diamond B question.

Quote:
Originally Posted by jim brierley View Post
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.
ouch!
Dave in MN is offline   Reply With Quote
Old 12-08-2020, 03:36 PM   #16
hardtimes
Senior Member
 
hardtimes's Avatar
 
Join Date: May 2010
Location: South California
Posts: 6,188
Default Re: Diamond B question.

Quote:
Originally Posted by rotorwrench View Post
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.
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.
hardtimes is offline   Reply With Quote
Old 12-08-2020, 08:55 PM   #17
Jack Shaft
BANNED
 
Join Date: Dec 2019
Posts: 1,196
Default Re: Diamond B question.

Big journal C crank helps too..
Jack Shaft is offline   Reply With Quote
Old 12-08-2020, 11:39 PM   #18
CWPASADENA
Senior Member
 
CWPASADENA's Avatar
 
Join Date: May 2010
Location: PASADENA, CA
Posts: 1,882
Default Re: Diamond B question.

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.
CWPASADENA is offline   Reply With Quote
Old 12-09-2020, 01:38 PM   #19
Hotrodfil
Senior Member
 
Hotrodfil's Avatar
 
Join Date: May 2010
Location: Norfolk UK
Posts: 213
Default Re: Diamond B question.

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.
Hotrodfil is offline   Reply With Quote
Old 12-10-2020, 06:41 PM   #20
Juggler
Senior Member
 
Juggler's Avatar
 
Join Date: Aug 2010
Location: Phoenix AZ/Bath UK
Posts: 481
Default Re: Diamond B question.

Weigh it!
Juggler is offline   Reply With Quote
Old 12-11-2020, 01:52 AM   #21
Chuck Sea/Tac
Senior Member
 
Chuck Sea/Tac's Avatar
 
Join Date: May 2010
Location: Between Seattle & Tacoma
Posts: 2,351
Default Re: Diamond B question.

Quote:
Originally Posted by Jack Shaft View Post
Big journal C crank helps too..
Down side is the rear flange the flywheel mounts to doesn’t have as much meat as the A crank. I suppose , because the flywheels were getting lighter as the roads got smoother. I was behind a friend when his flywheel flange sheared off. I don’t know if he was running a stock A flywheel, or a cut down.
Chuck Sea/Tac is offline   Reply With Quote
Old 12-11-2020, 08:47 AM   #22
Jack Shaft
BANNED
 
Join Date: Dec 2019
Posts: 1,196
Default Re: Diamond B question.

Flange's do fail. I will measure tonight against an A, will post the difference. I modify for better performance but don't race. In fact I'm quite happy with the power my modified flathead A puts out ( basically double of stock using my seat of the pants dyno), just want the long distance touring capability the B offers, I don't chase the dragon...yet .Plan on using a stock B flywheel behind the C crank and use modern fasteners with loctite to retain the flywheel. No lightened flywheel for this engine, want the mass for smooth drivability.
For racing(someday I might bump my head) I do have a late B that was bored to 4.060 and has balanced rods. I also have a 31 A block bored to .125 fitted with a beavertail A crank. The A block would get the lightest flywheel I could find, make a hillclimber..using the lightest rotating group I can muster insures fast application of torque, It might not last but will be fun while it does.
Jack Shaft is offline   Reply With Quote
Sponsored Links (Register now to hide all advertisements)
Old 12-13-2020, 02:31 AM   #23
hardtimes
Senior Member
 
hardtimes's Avatar
 
Join Date: May 2010
Location: South California
Posts: 6,188
Default Re: Diamond B question.

A lot of the twisted off crank tails has to do with the crank radius being made too small.
hardtimes is offline   Reply With Quote
Old 12-13-2020, 11:26 AM   #24
Jack Shaft
BANNED
 
Join Date: Dec 2019
Posts: 1,196
Default Re: Diamond B question.

Quote:
Originally Posted by Chuck Sea/Tac View Post
Down side is the rear flange the flywheel mounts to doesn’t have as much meat as the A crank. I suppose , because the flywheels were getting lighter as the roads got smoother. I was behind a friend when his flywheel flange sheared off. I don’t know if he was running a stock A flywheel, or a cut down.
Beavertail '28 A crankshaft flange : .3875

counterbalanced ford 'C' crankshaft flange : .3875
Jack Shaft is offline   Reply With Quote
Old 12-13-2020, 11:53 AM   #25
Ranchero50
Senior Member
 
Join Date: Aug 2019
Location: Hagerstown MD
Posts: 224
Lightbulb Re: Diamond B question.

Quote:
Originally Posted by hardtimes View Post
A lot of the twisted off crank tails has to do with the crank radius being made too small.
This as any good machinist knows. Sharp edge makes a fatigue point that WILL cause a failure.
__________________
Building a '29 Speedster, the hard way...
Ranchero50 is offline   Reply With Quote
Old 12-13-2020, 12:21 PM   #26
johnneilson
Senior Member
 
Join Date: Jun 2010
Location: 34.22 N 118.36 W
Posts: 1,044
Default Re: Diamond B question.

Sponsored Links (Register now to hide all advertisements)
There are lots of issues with the crank flanges, mainly due to the slinger and resultant reduction of material where it needs to be.
Once you have seen a flange broken off the crank, and the lack of material you will really start to wonder.
Now, there is quite the debate on putting the Chev 2 pc seal into the Mod"B"/"C" cranks.
Just as many different ways of doing it also but, to reduce the likelyhood of breaking off the flange the only way is to fill weld up the slinger area and remachine for the seal.

Reducing the flywheel weight does take a lot of stress off the flange, especially if you are revving the motor up.

John
__________________
As Carroll Smith wrote; All Failures are Human in Origin.
johnneilson is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Sponsored Links (Register now to hide all advertisements)


All times are GMT -5. The time now is 07:31 AM.