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Re: 3.58" crank
[Re: Crizila]
#1141602
12/22/11 12:44 PM
12/22/11 12:44 PM
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Joined: Aug 2003
Posts: 3,245
Between a rock & a hard place
cudadoug
master
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master
Joined: Aug 2003
Posts: 3,245
Between a rock & a hard place
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What's the intended use? For a 90% street car, a cast (MP/SCAT) crank will be fine. But if I were going to race one, I'd have it INTERNALLY balanced vs. external. Then you might as well take the money you're going to spend balancing and get the forged piece to begin with.
Last edited by cudadoug; 12/22/11 08:21 PM.
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Re: 3.58" crank
[Re: 416challenger]
#1141606
12/23/11 12:45 AM
12/23/11 12:45 AM
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Joined: Apr 2003
Posts: 799
north west LA
W2DODGE
super stock
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super stock
Joined: Apr 2003
Posts: 799
north west LA
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Nothing wrong with a stock crank. I made upwards of a thousand 10.60 passes in my 3,000 lb dart before it went into my buddies car for several seasons he spun a rod bearing not the cranks fault. I have also run cast 318 cranks in the same car in the 11.10 10.90 range.
Last edited by W2DODGE; 12/23/11 12:47 AM.
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Re: 3.58" crank
[Re: Rapid340]
#1141611
12/23/11 01:27 PM
12/23/11 01:27 PM
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Joined: Jul 2009
Posts: 413
Norway (old world)
Oyvind Mopar
mopar
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mopar
Joined: Jul 2009
Posts: 413
Norway (old world)
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Quote:
Density is increased by the forging process itself, even the cast steel cranks are lighter. Rotating weight can be a great place to go on a diet and often costs less than free. 
Is that correct? I do not think the density is much different if cast or forged, however, I am not so sure the socalled Cast steel cranks are really that!! Steel is difficult to cast, but iron is simple, and some people say their nodular cast iron cranks are cast steel!! 4% carbon make them all lighter than steel by appx 5%.
If the Scat 4" stroker cranks really was cast steel (I think I read so) I would buy them right away at 300$, or any comments??? 
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Re: 3.58" crank
[Re: Oyvind Mopar]
#1141612
12/23/11 02:18 PM
12/23/11 02:18 PM
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Joined: Sep 2004
Posts: 2,093
oberlin, Ohio
Rapid340
top fuel
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top fuel
Joined: Sep 2004
Posts: 2,093
oberlin, Ohio
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Quote: Quote:
Quote:
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Density is increased by the forging process itself, even the cast steel cranks are lighter. Rotating weight can be a great place to go on a diet and often costs less than free.
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Is that correct? I do not think the density is much different if cast or forged, however, I am not so sure the socalled Cast steel cranks are really that!! Steel is difficult to cast, but iron is simple, and some people say their nodular cast iron cranks are cast steel!! 4% carbon make them all lighter than steel by appx 5%.
If the Scat 4" stroker cranks really was cast steel (I think I read so) I would buy them right away at 300$, or any comments???
I would think that forging anything could increase its density but if that is not the case I stand corrected. I went to the scat website and they refer to the cast cranks as "CAST PROCOMP" but dont call them cast steel anywhere I can see. I think they have been advertised as cast steel ( by resellers? ) in the past and "cast 9000 series". Scat shows the weight of the SB mopar cast crank as four pounds less than the their 4340 forged crank (56lbs vs. 60lbs). Maybe these things being true cast steel is a myth.
1971 Factory Appearing Duster 340 11.000 @ 122 mph
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Re: 3.58" crank
[Re: Oyvind Mopar]
#1141614
12/24/11 10:15 AM
12/24/11 10:15 AM
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Joined: Jan 2003
Posts: 16,123
Grand Haven, MI
patrick
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 16,123
Grand Haven, MI
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Quote:
Quote:
Density is increased by the forging process itself, even the cast steel cranks are lighter. Rotating weight can be a great place to go on a diet and often costs less than free.
Is that correct? I do not think the density is much different if cast or forged, however, I am not so sure the socalled Cast steel cranks are really that!! Steel is difficult to cast, but iron is simple, and some people say their nodular cast iron cranks are cast steel!! 4% carbon make them all lighter than steel by appx 5%.
If the Scat 4" stroker cranks really was cast steel (I think I read so) I would buy them right away at 300$, or any comments???
no it's not unless the cast billet the forged crank is shaped from has serious voids....
steel casting isn't too tough, one of our customers does it all the time....
if a "cast steel" crank of the same dimensions is significantly lighter than a forged crank with the same volume of material, it's actually nodular (ductile) iron...where steel is the continuous phase, and there's spherical nodules of carbon dispersed throughout.
1976 Spinnaker White Plymouth Duster, /6 A833OD
1986 Silver/Twilight Blue Chrysler 5th Ave HotRod **SOLD!***
2011 Toxic Orange Dodge Charger R/T
2017 Grand Cherokee Overland
2014 Jeep Cherokee Latitude (holy crap, my daughter is driving)
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Re: 3.58" crank
[Re: W2DODGE]
#1141615
01/13/12 02:36 PM
01/13/12 02:36 PM
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Joined: Oct 2003
Posts: 21,345
Marysville, O-H-I-O
70Cuda383
Too Many Posts
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Too Many Posts
Joined: Oct 2003
Posts: 21,345
Marysville, O-H-I-O
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Quote:
I just got done skinning some big old swamp rabbits they aint got them on the left coast or road kill gumbo.
Quote:
Quote:
Nothing wrong with a stock crank. I made upwards of a thousand 10.60 passes in my 3,000 lb dart before it went into my buddies car for several seasons he spun a rod bearing not the cranks fault. I have also run cast 318 cranks in the same car in the 11.10 10.90 range.
LA as in Cajun country? Or LA as in Hollywood?
I know a guy from Louisiana that said he had some quick 318s. Coincidence?
Just saw the reply, How's retirement treating you Sherred?!
It's me, your favorite LT who was building the big block Dakota, was your Flt commander back in 05-06 time frame
(Ok, I assumed a little, might not have been your "favorite" Lt!)
**Photobucket sucks**
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Re: 3.58" crank
[Re: patrick]
#1141616
01/13/12 02:56 PM
01/13/12 02:56 PM
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Joined: Aug 2004
Posts: 2,128
sweden
sshemi
top fuel
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top fuel
Joined: Aug 2004
Posts: 2,128
sweden
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Quote:
Quote:
Quote:
Density is increased by the forging process itself, even the cast steel cranks are lighter. Rotating weight can be a great place to go on a diet and often costs less than free.
Is that correct? I do not think the density is much different if cast or forged, however, I am not so sure the socalled Cast steel cranks are really that!! Steel is difficult to cast, but iron is simple, and some people say their nodular cast iron cranks are cast steel!! 4% carbon make them all lighter than steel by appx 5%.
If the Scat 4" stroker cranks really was cast steel (I think I read so) I would buy them right away at 300$, or any comments???
no it's not unless the cast billet the forged crank is shaped from has serious voids....
steel casting isn't too tough, one of our customers does it all the time....
if a "cast steel" crank of the same dimensions is significantly lighter than a forged crank with the same volume of material, it's actually nodular (ductile) iron...where steel is the continuous phase, and there's spherical nodules of carbon dispersed throughout.
???
A forged thing is heavier then a cast thing.
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Re: 3.58" crank
[Re: 70Cuda383]
#1141618
01/13/12 03:48 PM
01/13/12 03:48 PM
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Joined: Jan 2003
Posts: 16,123
Grand Haven, MI
patrick
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 16,123
Grand Haven, MI
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Quote:
Quote:
???
A forged thing is heavier then a cast thing.
when made identically, yes.
but often times, Forged pistons are lighter than their cast counter-parts, because the stronger forging allows for less material at the same or greater overall strength.
Especially when you start comparing aftermarket forged pistons to heavy stock cast ones.
NO the density of steel is the same, whether it's cast or forged, 7820 kg/cubic meter. if 2 cranks are dimensionally identical (both displace the same volume), their mass will be the same even if one is CAST STEEL and the other is forged steel.
IF a crank is dimensionally identical, but the cast one is lighter, then it is not CAST STEEL. then it is most likely DUCTILE CAST IRON, also known as NODULAR IRON. it's density is about 10% less than steel, due to the much higher carbon content (which, in ductile iron is in the form of little spherical nodules dispersed though the continuous iron phase)...IIRC it's manganese as an alloying element that causes the carbon to form nodules vs. flakes like in traditional (grey) cast iron, but it's been 16 years since I had any metallurgy classes.
1976 Spinnaker White Plymouth Duster, /6 A833OD
1986 Silver/Twilight Blue Chrysler 5th Ave HotRod **SOLD!***
2011 Toxic Orange Dodge Charger R/T
2017 Grand Cherokee Overland
2014 Jeep Cherokee Latitude (holy crap, my daughter is driving)
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Re: 3.58" crank
[Re: patrick]
#1141619
01/13/12 04:24 PM
01/13/12 04:24 PM
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Joined: Jan 2003
Posts: 2,933
Finalnd, Perkele
jyrki
master
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master
Joined: Jan 2003
Posts: 2,933
Finalnd, Perkele
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It's just as easy to compress metal as it is to compress fluid. No can do, so, unless it's a porous casting,the weight of a cast and forged object with the same displacement should be the same. I'm as far of a scientist as you can get, but still I have a theory about cast and forged cranks differencies. Has anyone really weighed them? Because, my first tehory is that since the cast crank is weaker, they have to make the crankpin size heavier duty than in a forged crank, and since the counterweight sizes are the same, the crank needs external balancing. So, it's actually heavier, not lighter, than the forged crank (yes, haven't weighed for example a 383 forged and cast crank). The second theory is that because of the porousity, the counterweights of the cast crank are lighter... 
Plynouth VIP '67 TT IC EFI
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Re: 3.58" crank
[Re: jyrki]
#1141623
01/13/12 08:39 PM
01/13/12 08:39 PM
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Joined: Oct 2003
Posts: 21,345
Marysville, O-H-I-O
70Cuda383
Too Many Posts
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Too Many Posts
Joined: Oct 2003
Posts: 21,345
Marysville, O-H-I-O
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Quote:
It's just as easy to compress metal as it is to compress fluid. No can do, so, unless it's a porous casting,the weight of a cast and forged object with the same displacement should be the same. I'm as far of a scientist as you can get, but still I have a theory about cast and forged cranks differencies. Has anyone really weighed them? Because, my first tehory is that since the cast crank is weaker, they have to make the crankpin size heavier duty than in a forged crank, and since the counterweight sizes are the same, the crank needs external balancing. So, it's actually heavier, not lighter, than the forged crank (yes, haven't weighed for example a 383 forged and cast crank). The second theory is that because of the porousity, the counterweights of the cast crank are lighter...
Ok, I always thought forged was a little more dense than cast.
if they are the same density, and weigh the same...then why is a stock forged 440 crank heavy enough to internally balance, when a stock cast 440 crank is not heavy enough and needs external balance?
are they not cast steel?
**Photobucket sucks**
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Re: 3.58" crank
[Re: 70Cuda383]
#1141626
01/16/12 11:58 AM
01/16/12 11:58 AM
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Joined: Jan 2003
Posts: 16,123
Grand Haven, MI
patrick
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 16,123
Grand Haven, MI
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Quote:
Quote:
It's just as easy to compress metal as it is to compress fluid. No can do, so, unless it's a porous casting,the weight of a cast and forged object with the same displacement should be the same. I'm as far of a scientist as you can get, but still I have a theory about cast and forged cranks differencies. Has anyone really weighed them? Because, my first tehory is that since the cast crank is weaker, they have to make the crankpin size heavier duty than in a forged crank, and since the counterweight sizes are the same, the crank needs external balancing. So, it's actually heavier, not lighter, than the forged crank (yes, haven't weighed for example a 383 forged and cast crank). The second theory is that because of the porousity, the counterweights of the cast crank are lighter...
Ok, I always thought forged was a little more dense than cast.
if they are the same density, and weigh the same...then why is a stock forged 440 crank heavy enough to internally balance, when a stock cast 440 crank is not heavy enough and needs external balance?
are they not cast steel?
either they are ductile iron (9% lighter) or they are different geometry (less material)
I'm pretty sure they're actually ductile iron (nodular iron), not cast steel though.
1976 Spinnaker White Plymouth Duster, /6 A833OD
1986 Silver/Twilight Blue Chrysler 5th Ave HotRod **SOLD!***
2011 Toxic Orange Dodge Charger R/T
2017 Grand Cherokee Overland
2014 Jeep Cherokee Latitude (holy crap, my daughter is driving)
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Re: 3.58" crank
[Re: RUNCHARGER]
#1141629
01/17/12 11:40 PM
01/17/12 11:40 PM
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Joined: Oct 2008
Posts: 1,176
East Coast
A/MP
super stock
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super stock
Joined: Oct 2008
Posts: 1,176
East Coast
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This is the real deal with cast factory cranks. A Chrysler factory crank LA motor will take 600HP in a light weight car 2800lbs. What is different between cast and forged(othet than metalugy) is the stress cyclces that the metal can endure. A 360 cast crank with 70,000+ miles whether light or hard use has reached a point wear the metal memory starts getting alzheimers. When the metal structure starts to move with the stress of racing it forgets its original place and starts moving away from its as cast structure. Once that happens the greater the chances of fracture of the metal structure and eventual failure. All forged china cranks whether scat,eagle,ohio,callies come from the same factory. When the china economy becomes stressed, the chineses look for a cheaper way out. This means a cheaper(quality) product.Products that were manufactued 2010,2011,? many fit this proverb. A real Callies crank is $1500.00+. Can it fail? Sure but the chances are slim. Look on ebay for a race W7 or W9 motor. Many of them are only test laps,and they with run low 9's as is. With cam and carb change high 8's. Someone else did all the engineering and at 15K not a bad deal, respectively.
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