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440 Blocks #2671174
06/28/19 03:01 PM
06/28/19 03:01 PM
Joined: Jan 2005
Posts: 1,768
Keymar, MD
DusterKid Offline OP
top fuel
DusterKid  Offline OP
top fuel

Joined: Jan 2005
Posts: 1,768
Keymar, MD
Always hear about 440 blocks cracking. Would like to do a poll to see who has personally have/haven't cracked a block. (Cracked caused by stress, etc, not from a rod breaking and going out the side, etc.)

Have you cracked a 440 block
single choice
Votes accepted starting: 06/28/19 02:59 PM
You must vote before you can view the results of this poll.
Last edited by DusterKid; 06/28/19 03:02 PM.
Re: 440 Blocks [Re: DusterKid] #2671191
06/28/19 03:30 PM
06/28/19 03:30 PM
Joined: Jan 2003
Posts: 15,439
Val-haul-ass... eventually
B
BradH Offline
Taking time off to work on my car
BradH  Offline
Taking time off to work on my car
B

Joined: Jan 2003
Posts: 15,439
Val-haul-ass... eventually
I voted "No", but think it's just a matter of time as I keep stepping up the power level with an old factory block. And that's why I have two spares in garage. luck

Re: 440 Blocks [Re: DusterKid] #2671192
06/28/19 03:31 PM
06/28/19 03:31 PM
Joined: Aug 2003
Posts: 4,662
On the parachute mount
N
n20mstr Offline
master
n20mstr  Offline
master
N

Joined: Aug 2003
Posts: 4,662
On the parachute mount
I have an RB that I have used...went 9.0's with nitrous in a 3600lb car. Alum rods, stock stroke and stock main caps
I have been told..."keep it from detonating, it might live"....and " if it don't crack right away, it might last.."

Its sitting in my basement now, and I keep telling myself im going to use that shortblock again someday

I voted NO

Last edited by n20mstr; 06/28/19 03:38 PM.

....BAD A$$ STREET CAR.....
Re: 440 Blocks [Re: n20mstr] #2671245
06/28/19 05:43 PM
06/28/19 05:43 PM
Joined: Feb 2005
Posts: 20,116
PA.
pittsburghracer Offline
"Little"John
pittsburghracer  Offline
"Little"John

Joined: Feb 2005
Posts: 20,116
PA.
275 passes running 8.60’s in my Daytona. 440source assembly and their steel caps. When I tore it down for rebuild it was cracked up thru the mains. It never leaked a drop of water.


1970 Duster
Edelbrock headed 408
5.984@112.52
422 Indy headed small block
5.982@112.56 mph
9.42@138.27

Livin and lovin life one day at a time




Re: 440 Blocks [Re: pittsburghracer] #2671255
06/28/19 06:14 PM
06/28/19 06:14 PM
Joined: Aug 2003
Posts: 43,007
Bend,OR USA
C
Cab_Burge Offline
I Win
Cab_Burge  Offline
I Win
C

Joined: Aug 2003
Posts: 43,007
Bend,OR USA
Originally Posted by pittsburghracer
275 passes running 8.60’s in my Daytona. 440source assembly and their steel caps. When I tore it down for rebuild it was cracked up thru the mains. It never leaked a drop of water.

I've seen the same thing he has, aluminum rods with a stock stroke OEM forged steel crankshaft cracked between #1 nd #3 cylinders at the bottom of the cylinder walls into the #2 main webbing through it to the bearing surface whiney shruggy
I had a OEM 426 M.W. block crack the same place but it broke a rod due to spinning the #1 rod bearing and the rod broke and hit the side of the block on the left front shruggy


Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
Re: 440 Blocks [Re: Cab_Burge] #2671280
06/28/19 07:02 PM
06/28/19 07:02 PM
Joined: Jan 2003
Posts: 14,479
So. Burlington, Vt.
F
fast68plymouth Offline
I Live Here
fast68plymouth  Offline
I Live Here
F

Joined: Jan 2003
Posts: 14,479
So. Burlington, Vt.
3 customer motors.

2- 440’s and a 493.

575hp, 625hp, 695hp

And easily a dozen or more cracked stock steel 440 cranks after they’ve been in bracket cars for a while........usually multiple cracks.
Actually....... more uncommon to have it not be cracked.


68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123
Dealer for Comp Cams/Indy Heads
Re: 440 Blocks [Re: fast68plymouth] #2671345
06/28/19 10:33 PM
06/28/19 10:33 PM
Joined: Feb 2005
Posts: 20,116
PA.
pittsburghracer Offline
"Little"John
pittsburghracer  Offline
"Little"John

Joined: Feb 2005
Posts: 20,116
PA.
Originally Posted by fast68plymouth
3 customer motors.

2- 440’s and a 493.

575hp, 625hp, 695hp

And easily a dozen or more cracked stock steel 440 cranks after they’ve been in bracket cars for a while........usually multiple cracks.
Actually....... more uncommon to have it not be cracked.





But when I was running high 9’s with Stock cranks after 3 years when I did a rebuild I stopped even magnifluxing then. They always showed cracks so I just started over with a fresh crank and threw that one on the scrap pile


1970 Duster
Edelbrock headed 408
5.984@112.52
422 Indy headed small block
5.982@112.56 mph
9.42@138.27

Livin and lovin life one day at a time




Re: 440 Blocks [Re: DusterKid] #2671375
06/29/19 12:34 AM
06/29/19 12:34 AM
Joined: Nov 2015
Posts: 870
Missouri
J
jwb123 Offline
super stock
jwb123  Offline
super stock
J

Joined: Nov 2015
Posts: 870
Missouri
When you get to the 650-700HP range they will fail. I never blew one up, but when you take them apart to freshen, they have cracks and problems. No 2 main if you use stock caps will always be the one to crack and break. I had one filled with concrete and the cylinders started to fail and it pushed so hard on the concrete it cracked between the freeze plugs, never leaked water and never blew up, but it was junk. Last stock block I did had a main girdle, and filled block with side bolt steel main caps, ran it 4 years, but when I took it apart to freshen, it was cracked along the oil hole that fed the main to the cam bearing on number two main.

Re: 440 Blocks [Re: jwb123] #2671431
06/29/19 08:44 AM
06/29/19 08:44 AM
Joined: May 2005
Posts: 1,944
Apollo, PA.
B1MAXX Offline
top fuel
B1MAXX  Offline
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Joined: May 2005
Posts: 1,944
Apollo, PA.
I had one crack a main....never exploded. I saw one that split a cylinder wall was .080 at best on one side, when you looked at the boss for the front camshaft bearing the hole was severely of center, I chalked that up to core shift.

Re: 440 Blocks [Re: DusterKid] #2671441
06/29/19 09:17 AM
06/29/19 09:17 AM
Joined: Oct 2007
Posts: 4,205
New York
polyspheric Offline
master
polyspheric  Offline
master

Joined: Oct 2007
Posts: 4,205
New York
I see the pattern of where they can break.
My question: IDT future breakage can be accurately predicted by HP alone. Exactly what factors are involved?
Actual maximum cylinder pressure at highest point too near TDC (like nitrous)
Very low rod ratio (4-1/2" stroke, BBC + .400" rod = 1.45:1)
Knock
Crank stiffness (worse with stroke increase, BBC rod journal)
B size mains (smaller crank, more saddle and cap area) vs. RB (bigger crank, smaller caps)

IIRC generally accepted that supercharged power is easier on the bottom end because the max cylinder pressure is less (than the same power NA) and occurs over a longer rotation period. But how much?


Boffin Emeritus
Re: 440 Blocks [Re: DusterKid] #2671484
06/29/19 10:57 AM
06/29/19 10:57 AM
Joined: Jun 2004
Posts: 119
SE VA
hemibee69 Offline
member
hemibee69  Offline
member

Joined: Jun 2004
Posts: 119
SE VA
I personally have cracked 2 different stock 440 blocks, couple hundred runs on each i guess. No girdle or block filler. #2 main saddle cracked up into the cyl wall, same place both blocks. Water in the oil the first clue. Did not throw a rod either time. Took it apart as soon as the milky oil showed up. Eagle 4.15" crank, eagle rods, weisco pistons, B1BS heads, Alum main caps both times. 35 deg timing, 9.00 @ 145 2800lbs, 7200 rpm at the stripe.. Put a world block in no more cracks, 8 years later. On a side note I put 600 runs on aa stock block, crank, main caps, no girdle or block fill. But it had aluminum rods, the rods had .25" side clearance from rubbing on the crank sides. You know what the old saying" it is just a matter of time before a stock block fails at higher power levels. John

Last edited by hemibee69; 06/29/19 11:08 AM.

1969 Orig Hemi Super Bee Post 4 spd Red on Red (Sold sadly)
1970 Cuda Drag car 500" B1/BS 8.63 @ 155 mph
1970 Challenger SE 383 4 bbl A/C PB PS Leather
1971 Orig 440+6 Cuda 4 spd Shaker In-Violet
Re: 440 Blocks [Re: hemibee69] #2671490
06/29/19 11:08 AM
06/29/19 11:08 AM
Joined: Jan 2003
Posts: 30,947
Oregon
A
AndyF Offline
I Win
AndyF  Offline
I Win
A

Joined: Jan 2003
Posts: 30,947
Oregon
My 505 cracked the main web after a bunch of 800 hp dyno pulls. The engine didn't leak water and oil pressure was solid but when we pulled it apart for maintenance we could see the crack.

Re: 440 Blocks [Re: DusterKid] #2671492
06/29/19 11:12 AM
06/29/19 11:12 AM
Joined: Jan 2003
Posts: 686
Houston, Texas
F
FastOrange Offline
mopar
FastOrange  Offline
mopar
F

Joined: Jan 2003
Posts: 686
Houston, Texas
Even using an ARP main stud kit, Upon inspection, my main caps machined mating surfaces, show fretting damage. In other words, the caps are moving. I suspect at high RPM loads in the 675 HP range.
Sold off several stock blocks when the World Blocks debuted. Unfortunately, the World blocks ceased production.

Re: 440 Blocks [Re: DusterKid] #2671532
06/29/19 12:06 PM
06/29/19 12:06 PM
Joined: Jan 2003
Posts: 15,439
Val-haul-ass... eventually
B
BradH Offline
Taking time off to work on my car
BradH  Offline
Taking time off to work on my car
B

Joined: Jan 2003
Posts: 15,439
Val-haul-ass... eventually
We got a 30+% hit rate on cracked 440 blocks here... definitely not a statistical outlier on the probability.

Re: 440 Blocks [Re: BradH] #2671618
06/29/19 03:57 PM
06/29/19 03:57 PM
Joined: Jan 2003
Posts: 30,947
Oregon
A
AndyF Offline
I Win
AndyF  Offline
I Win
A

Joined: Jan 2003
Posts: 30,947
Oregon
My guess on the statistics is that a very low percentage of the low hp blocks crack while a very high percentage of the high hp blocks crack. I doubt the curve is linear, most likely exponential. They probably all crack once you get above 900 hp NA. Maybe 50% of them crack at the 800 hp level and 25% crack at 700 hp.

Re: 440 Blocks [Re: FastOrange] #2671621
06/29/19 04:12 PM
06/29/19 04:12 PM
Joined: Jan 2003
Posts: 1,237
North Central, Indiana
Roughbird72 Offline
pro stock
Roughbird72  Offline
pro stock

Joined: Jan 2003
Posts: 1,237
North Central, Indiana
Originally Posted by FastOrange
Even using an ARP main stud kit, Upon inspection, my main caps machined mating surfaces, show fretting damage. In other words, the caps are moving. I suspect at high RPM loads in the 675 HP range.
Sold off several stock blocks when the World Blocks debuted. Unfortunately, the World blocks ceased production.


I doubt you'll find caps that don't walk in anything that's being twisted harder than passenger car use. twocents


72 Plymouth Roadrunner 11.08@123.25
Re: 440 Blocks [Re: Roughbird72] #2671661
06/29/19 06:55 PM
06/29/19 06:55 PM
Joined: Mar 2006
Posts: 9,791
MI, usa
dvw Offline
master
dvw  Offline
master

Joined: Mar 2006
Posts: 9,791
MI, usa
Unported-1 Indys, stock cross ram, .650 roller, 4.150 Mopar crank, 498, 660hp, never saw 6900rpm. Pulled the front 2 main webs right out of the block. Broke the crank in half right in front of the #3 main.
Doug

Re: 440 Blocks [Re: DusterKid] #2671679
06/29/19 07:47 PM
06/29/19 07:47 PM
Joined: Sep 2006
Posts: 1,440
central ohio
N
nss guy Offline
pro stock
nss guy  Offline
pro stock
N

Joined: Sep 2006
Posts: 1,440
central ohio
voted yes, have had 2 blocks that showed cracks in the main webbing when cleaned up and mag'ed before rebuild both had about 450+ passes on them. The car runs low 10's, probably around 650hp. 4.15 crank, shift at 6200 and trap at 6700 or so. We caught the cracks early, probably no problem for a street car but race??? Who knows.

Re: 440 Blocks [Re: nss guy] #2671808
06/30/19 08:23 AM
06/30/19 08:23 AM
Joined: Jan 2005
Posts: 1,768
Keymar, MD
DusterKid Offline OP
top fuel
DusterKid  Offline OP
top fuel

Joined: Jan 2005
Posts: 1,768
Keymar, MD
Thanks for the replies guy. I'm looking to build a 625-650hp engine to help get my car to run 6.50s on a hot muggy day to be able to run a 6.50 index class. I've been running 440's for years but just stock stroke stuff and nothing over the top. I have both 400 and 440 blocks. My gut tells me to go with a 400 block, but my wallet says 440 since I would need less parts. I think I would be fine with a 440 as I'd like it to run on pump gas. I'd like to shift at 6000 and never turn it over 6500. But if it would crack than I'd be kicking myself...Decisions decisions

Re: 440 Blocks [Re: DusterKid] #2671834
06/30/19 09:39 AM
06/30/19 09:39 AM
Joined: May 2005
Posts: 1,944
Apollo, PA.
B1MAXX Offline
top fuel
B1MAXX  Offline
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Joined: May 2005
Posts: 1,944
Apollo, PA.
Don't let worrying about a crack stop you from building something. If an aftermarket block isn't in the budget, then its not in the budget. Don't let that stop you. twocents

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