2.3 Crankshaft Science
Dec 18, 2013, 07:18 AM
#1
Evolving Member
Thread Starter
2.3 Crankshaft Science
I've searched this subject but to no avail now time to ask the pros..
If the Oem 2.4 Crankshaft is inherently weak because there isn't much journal overlap, how can an aftermarket crank have more journal overlap. Shouldn't the cranks measure the same dimensions? I understand the different manufacturing processes. But that shouldn't change the dimensions between the Throws and Mains. Unless the weakness is due to the radius at the rod journal ends only and not attributed to the lack of overlap.
Please don't start the billet is better than forged hoopla!
If the Oem 2.4 Crankshaft is inherently weak because there isn't much journal overlap, how can an aftermarket crank have more journal overlap. Shouldn't the cranks measure the same dimensions? I understand the different manufacturing processes. But that shouldn't change the dimensions between the Throws and Mains. Unless the weakness is due to the radius at the rod journal ends only and not attributed to the lack of overlap.
Please don't start the billet is better than forged hoopla!
Dec 18, 2013, 08:01 AM
#3
Evolving Member
Thread Starter
Dec 18, 2013, 08:25 AM
#4
The only issues I’ve seen with any 2.4 crank is predetonation. The OEM cranks have the radius/fillet on the rod and main journals. When they are made, extreme pressure is used. This can cause hot spots in certain areas resulting in a potential weak spot. This weak spot is normally found from detonation. When the crank is rotating to TDC, the detonation causes the crank to slow down causing stress on the rod and main journals. With the 2.4 having a longer stroke, the torque is greater which is why we see this in the 2.4 cranks more often.
I have seen a few 2.0 cranks having cracks in the same spots as the 2.4 but they are not as common.
This is why I nitride the cranks before I build any 4G motor. I have yet to have any crank damage since.
I have seen a few 2.0 cranks having cracks in the same spots as the 2.4 but they are not as common.
This is why I nitride the cranks before I build any 4G motor. I have yet to have any crank damage since.
Last edited by evolve_VIII; Dec 18, 2013 at 08:28 AM.
Dec 18, 2013, 08:54 AM
#5
Evolving Member
Thread Starter
The only issues I’ve seen with any 2.4 crank is predetonation. The OEM cranks have the radius/fillet on the rod and main journals. When they are made, extreme pressure is used. This can cause hot spots in certain areas resulting in a potential weak spot. This weak spot is normally found from detonation. When the crank is rotating to TDC, the detonation causes the crank to slow down causing stress on the rod and main journals. With the 2.4 having a longer stroke, the torque is greater which is why we see this in the 2.4 cranks more often.
I have seen a few 2.0 cranks having cracks in the same spots as the 2.4 but they are not as common.
This is why I nitride the cranks before I build any 4G motor. I have yet to have any crank damage since.
I have seen a few 2.0 cranks having cracks in the same spots as the 2.4 but they are not as common.
This is why I nitride the cranks before I build any 4G motor. I have yet to have any crank damage since.
Dec 18, 2013, 09:11 AM
#6
Maybe other engine gurus may chime in but I did a lot of research before I went with the 2.4.
Last edited by evolve_VIII; Dec 18, 2013 at 09:15 AM.
Dec 18, 2013, 10:40 AM
#7
I've searched this subject but to no avail now time to ask the pros..
If the Oem 2.4 Crankshaft is inherently weak because there isn't much journal overlap, how can an aftermarket crank have more journal overlap. Shouldn't the cranks measure the same dimensions? I understand the different manufacturing processes. But that shouldn't change the dimensions between the Throws and Mains. Unless the weakness is due to the radius at the rod journal ends only and not attributed to the lack of overlap.
Please don't start the billet is better than forged hoopla!
If the Oem 2.4 Crankshaft is inherently weak because there isn't much journal overlap, how can an aftermarket crank have more journal overlap. Shouldn't the cranks measure the same dimensions? I understand the different manufacturing processes. But that shouldn't change the dimensions between the Throws and Mains. Unless the weakness is due to the radius at the rod journal ends only and not attributed to the lack of overlap.
Please don't start the billet is better than forged hoopla!
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Dec 18, 2013, 10:52 AM
#8
Evolving Member
Thread Starter
Dec 18, 2013, 11:23 AM
#9
From what I could find, Cosworth does not make a 2.4 kit. Im guessing that making a 100mm crank with larger overlap, you will have to cut too much clearance out of the block for it to fit. Running the turbo tuff rods and 100mm crank you have to notch the block.
Looks like you have to use their rods.
Cosworth 2.2L Mitsubishi 4G63 stroker kit assembly is one of the best way to add performance to your engine.
Technical Features.
A high power Mitsubishi 4G63 engine places enormous amounts of stress on various engine components including the heart of the engine, the crankshaft. Employing F1 engine technology and Finite Element Analysis (FEA), Cosworth has engineered a 94mm (2.2L) crankshaft that is 50%-80% stronger in critical areas than typical aftermarket parts. By enlarging the rod journal diameter and increasing rod to main journal overlap, high stress areas have been strengthened and crankshaft flex has been reduced resulting in a component that is dependable for all forms of racing. For maximum reliability each crankshaft features the same oiling scheme as our world class four cylinder race engines that have won all forms of racing including WRC, BTCC, and Formula Atlantic. Additional features include journal radius and various machined areas that are optimized for maximum strength. These features, when combined with Cosworth matched motorsport grade engine components, will yield potentially big gains in torque while allowing the engine to rotate and produce power in the higher rpm range.
Looks like you have to use their rods.
Cosworth 2.2L Mitsubishi 4G63 stroker kit assembly is one of the best way to add performance to your engine.
Technical Features.
A high power Mitsubishi 4G63 engine places enormous amounts of stress on various engine components including the heart of the engine, the crankshaft. Employing F1 engine technology and Finite Element Analysis (FEA), Cosworth has engineered a 94mm (2.2L) crankshaft that is 50%-80% stronger in critical areas than typical aftermarket parts. By enlarging the rod journal diameter and increasing rod to main journal overlap, high stress areas have been strengthened and crankshaft flex has been reduced resulting in a component that is dependable for all forms of racing. For maximum reliability each crankshaft features the same oiling scheme as our world class four cylinder race engines that have won all forms of racing including WRC, BTCC, and Formula Atlantic. Additional features include journal radius and various machined areas that are optimized for maximum strength. These features, when combined with Cosworth matched motorsport grade engine components, will yield potentially big gains in torque while allowing the engine to rotate and produce power in the higher rpm range.
Dec 18, 2013, 02:09 PM
#10
Evolving Member
Thread Starter
Yeah I knew Cosworth only had 2.2L strokers I assumed he meant the 94mm, I'm not sure what the 94mm OEM crank throw overlaps look like.
I think almost all crankshafts aftermarket or OEM have radius-ed journals. Has anyone here ever broke a Manley Crankshaft?
I think almost all crankshafts aftermarket or OEM have radius-ed journals. Has anyone here ever broke a Manley Crankshaft?
Dec 19, 2013, 10:02 AM
#12
There is a 93mm diesel crank from the 4D68 that is commonly machined to work in the 4G63 but its EDM/JDM only and cost prohibitive unless you are in Asia or Europe where they are prevalent.
We have a broke Manley 100mm here right now. There is so much trash in the motor though it could be it was oil starvation that lead to a spun main, an inclusion in the crank, etc. Where it broke is not where the OE crank breaks. This was lower down and slightly different shaped so I definitely feel this was the exception rather than the rule.
We have had 3 OE 100mm cranks break (out of 100+ motors) and all were on E85 so we can rule out the pre-det as a likely cause I think. Torque wasnt over 540 on any of them and I have run over 600 on the OE personally. We now have the cranks all magnafluxed if we use an OE. While we prefer the K1 100mm the price is the nearly the same as the Manley and some customers want to try the OE rather than spend the money. The Eagle hasnt ever broke and is only $650, cheap insurance, so it doesnt make sense to even bother with an OE.
We have a broke Manley 100mm here right now. There is so much trash in the motor though it could be it was oil starvation that lead to a spun main, an inclusion in the crank, etc. Where it broke is not where the OE crank breaks. This was lower down and slightly different shaped so I definitely feel this was the exception rather than the rule.
We have had 3 OE 100mm cranks break (out of 100+ motors) and all were on E85 so we can rule out the pre-det as a likely cause I think. Torque wasnt over 540 on any of them and I have run over 600 on the OE personally. We now have the cranks all magnafluxed if we use an OE. While we prefer the K1 100mm the price is the nearly the same as the Manley and some customers want to try the OE rather than spend the money. The Eagle hasnt ever broke and is only $650, cheap insurance, so it doesnt make sense to even bother with an OE.
Dec 19, 2013, 11:34 AM
#13
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Good thread. I always love when facts are used in technical discussions, and not "I heard...".
I'm curious if anyone knows whether Cosworth manufactures any of the components in their 4G63 short/longblock. When we still ordered a lot of Cosworth Subaru stuff, I recall that they only actually manufactured the pistons (which are still fantastic because of their proprietary piston coatings), and procured the other components for their blocks from outside companies. For example, the rods are just Carillo rods in the Cosworth shortblock, the cranks for Subaru were all made in Southern California and shipped to the UK for assembly, and ARP hardware was used. I'm just leary of whether their 4G63 short/long blocks would actually be worth the high cost of the brand name if it is still the case that they do not manufacture most/all of the parts used in applications other than high-end motorsports.
If anyone has any actual info, I'd love to hear it.
I'm curious if anyone knows whether Cosworth manufactures any of the components in their 4G63 short/longblock. When we still ordered a lot of Cosworth Subaru stuff, I recall that they only actually manufactured the pistons (which are still fantastic because of their proprietary piston coatings), and procured the other components for their blocks from outside companies. For example, the rods are just Carillo rods in the Cosworth shortblock, the cranks for Subaru were all made in Southern California and shipped to the UK for assembly, and ARP hardware was used. I'm just leary of whether their 4G63 short/long blocks would actually be worth the high cost of the brand name if it is still the case that they do not manufacture most/all of the parts used in applications other than high-end motorsports.
If anyone has any actual info, I'd love to hear it.
Last edited by Touge86; Dec 19, 2013 at 12:02 PM.
Dec 19, 2013, 07:49 PM
#15
Evolving Member
Thread Starter
There is a 93mm diesel crank from the 4D68 that is commonly machined to work in the 4G63 but its EDM/JDM only and cost prohibitive unless you are in Asia or Europe where they are prevalent.
We have a broke Manley 100mm here right now. There is so much trash in the motor though it could be it was oil starvation that lead to a spun main, an inclusion in the crank, etc. Where it broke is not where the OE crank breaks. This was lower down and slightly different shaped so I definitely feel this was the exception rather than the rule.
We have had 3 OE 100mm cranks break (out of 100+ motors) and all were on E85 so we can rule out the pre-det as a likely cause I think. Torque wasnt over 540 on any of them and I have run over 600 on the OE personally. We now have the cranks all magnafluxed if we use an OE. While we prefer the K1 100mm the price is the nearly the same as the Manley and some customers want to try the OE rather than spend the money. The Eagle hasnt ever broke and is only $650, cheap insurance, so it doesnt make sense to even bother with an OE.
We have a broke Manley 100mm here right now. There is so much trash in the motor though it could be it was oil starvation that lead to a spun main, an inclusion in the crank, etc. Where it broke is not where the OE crank breaks. This was lower down and slightly different shaped so I definitely feel this was the exception rather than the rule.
We have had 3 OE 100mm cranks break (out of 100+ motors) and all were on E85 so we can rule out the pre-det as a likely cause I think. Torque wasnt over 540 on any of them and I have run over 600 on the OE personally. We now have the cranks all magnafluxed if we use an OE. While we prefer the K1 100mm the price is the nearly the same as the Manley and some customers want to try the OE rather than spend the money. The Eagle hasnt ever broke and is only $650, cheap insurance, so it doesnt make sense to even bother with an OE.
The Manley you have that's broken is it the forged or billet version ?
The 93mm Oem is the one I was referencing to not many people know about that crank. It's used to make a 2.2L I'm trying to figure out that missing 1MM we normally need to make a 2.2
Does the Eagle have oiling issues I have read in another thread that it's the reason Dave Buschur doesn't use them anymore but I don't know if that's the reason or not.