Manley Billet 100mm crank - Cracked
The following users liked this post:
2006EvoIXer (May 3, 2018)
May 3, 2018, 07:14 AM
#24
Evolved Member
Manley crank and K1 are made in China, but so are many other parts, such as compressor wheels used by well known turbo companies, and even oem parts used by car manufacturers. The fact that something is made in Chine does not mean that it is necessarily of low quality, it can be yes, but it is often not the case. It's all down to what you buy from which Chinese company.
For the record, K1 cranks are better than manley, higher quality casting and forging processes, more precise tooling, higher grade alloy. I have yet to see a K1 crank crack. Oem 4g64 crank is of very high quality in all aspects, it can certainly take 700+whp. The 4g63 one has even higher fatigue and torsional stress resistance which makes it able to handle an excess of 1000whp.
My advice, use an oem 100mm stroke crank.
Marios
For the record, K1 cranks are better than manley, higher quality casting and forging processes, more precise tooling, higher grade alloy. I have yet to see a K1 crank crack. Oem 4g64 crank is of very high quality in all aspects, it can certainly take 700+whp. The 4g63 one has even higher fatigue and torsional stress resistance which makes it able to handle an excess of 1000whp.
My advice, use an oem 100mm stroke crank.
Marios
May 3, 2018, 09:02 AM
#25
Manley crank and K1 are made in China, but so are many other parts, such as compressor wheels used by well known turbo companies, and even oem parts used by car manufacturers. The fact that something is made in Chine does not mean that it is necessarily of low quality, it can be yes, but it is often not the case. It's all down to what you buy from which Chinese company.
For the record, K1 cranks are better than manley, higher quality casting and forging processes, more precise tooling, higher grade alloy. I have yet to see a K1 crank crack. Oem 4g64 crank is of very high quality in all aspects, it can certainly take 700+whp. The 4g63 one has even higher fatigue and torsional stress resistance which makes it able to handle an excess of 1000whp.
My advice, use an oem 100mm stroke crank.
Marios
For the record, K1 cranks are better than manley, higher quality casting and forging processes, more precise tooling, higher grade alloy. I have yet to see a K1 crank crack. Oem 4g64 crank is of very high quality in all aspects, it can certainly take 700+whp. The 4g63 one has even higher fatigue and torsional stress resistance which makes it able to handle an excess of 1000whp.
My advice, use an oem 100mm stroke crank.
Marios
Are you BS delete? Just curious. The topic has been of interest to me after reading the "White Paper" from Jacks Trans
Heres an excerpt / Pasted here:
Imagine the forces the crank has to endure at high RPM. Lets say you are zinging your engine up to 8000RPM. At that speed your crank is twisting forward and back 133 times a second!! This whip is not gentle either, it's like a large hammer beating on your drive-train 133 times a second. When we think of what a crank is going through at high RPM, we think if just how fast it is rotating and how amazing it is that it can hold the power which we are forcing through it, but that's not all. It is also flexing and twisting while it is rotating and 133 times a second at your 8000RPM rev limit. It's something our minds just can't comprehend. This whip creates a series of problems for us.Torsional whip is very destructive. Bolts will work their way loose in various places, you get a buzz from the engine, clutches drag and break, crankshafts break
The following users liked this post:
MinusPrevious (May 3, 2018)
May 3, 2018, 09:26 AM
#27
Combustion is actually occurring every 180 degree, so the "beating" happens twice per crankshaft revolution. Here's what I think he meant:
Imagine the forces the crank has to endure at high RPM. Lets say you are zinging your engine up to 8000RPM. At that speed your crank is twisting forward and back 133 times a second!! This whip is not gentle either, it's like a large hammer beating on your drive-train 267 times a second. When we think of what a crank is going through at high RPM, we think if just how fast it is rotating and how amazing it is that it can hold the power which we are forcing through it, but that's not all. It is also flexing and twisting while it is rotating at 133 revolutions a second at your 8000RPM rev limit. It's something our minds just can't comprehend. This whip creates a series of problems for us.Torsional whip is very destructive. Bolts will work their way loose in various places, you get a buzz from the engine, clutches drag and break, crankshafts break
May 3, 2018, 09:32 AM
#28
Rs motors have also cracked OEM cranks. Strong heavy unsprung clutches, wheel hop, slicks and a tough environment are hard on things. Other factors could be vibration,lack of a good harmonic balancer, knock etc..
The 100mm crank has more leverage and less material in specific areas compared to a 88mm crank. Hard to have it perfect both ways.
This is also something to think about.
I'm not trying to call anyone's baby ugly or step on any toes. Take a step back and look at every situation and the facts.
Lets not forget that plenty of people have cracked OEM or other 100mm cranks with power,rpm,detonation or sheer force . Its 14% larger then the stock 88mm crank and deals with more leverage. Everything has its limits.
Bigger stroke is going to increase Harmonics. Here are a few things worth noting.
1) Most people change the crank and they don't add a good dampner (ATI) to help deal with this. The stock dampner is for a stock crank/engine and is over a decade old at this point. A good dampner is going to help any engine with aftermarket rods/pistons of any stroke. Its often overlooked and people want to point fingers at something else. Our engines can easily make 150-250hp a cylinder so everything needs to be looked at.
2) There has been a tuning learning curve for most over the past decade. If you look back the information is there on timing used,afr and results. The big crank doesn't deal with being rattled like the smaller crank but anything can break. A clean dyno sheet on low smoothing tells the story for the people that know. Ever look at one on high smoothing and its still wavy. Or Jagged? Not how I want my engine to run.
3) Everyone is a tuner and does endless road logs "getting it right" on a single knock sensor with Hobbyist software. This has its draw backs if the engine isn't running good. How accurate is the software, old knock sensor, ignition system barreling down the road? How many people have tuned their stock engine bearings out tuning on their own. Professionals with the right tools and feedback are a worthwhile investment. Or the tuner that runs 35psi on pump gas and is proud of it. Thats careless or not knowing any better. I've seen countless examples
4) Hang a big heavy twin/triple disk that doesn't slip to cause even more stress on the drivetrain. Clutch technology has gotten extremely good and affordable over the years. Something has to give.
5) The RS motors car has broken a few stock cranks IIRC. Its well tuned but I'd guess between a strong twin disk and chattering the tires on a loose road course surface its transmitting the shock into the crank and drivetrain.
6) Leverage/material limits.
7) A well balanced assembly . Remember, good and cheap hardly work out. Going to a machine shop that has a great reputation is worth the money. The engine builder also should have ALL the proper tools to check that work and assemble the engine.
8) TScomp uses and builds ALOT of 100mm Manley crank engines . He's tuned/built these cars for awhile and they seem to live well. If the crank was a problem would he continue to run it?
The big crank has its limits like anything else. With good tuning and parts selection it should live a decent life at moderate levels.
FWIW. I've got a Manley billet 94mm, ATI and well balanced assembly thats living well .
These cars are very rewarding if you take the time to research,build them and tune them correctly. Attention to detail always pays off.
https://en.wikipedia.org/wiki/Torsional_vibration
Last edited by Abacus; May 3, 2018 at 09:37 AM.
The following users liked this post:
N1MR0D (May 27, 2018)
May 3, 2018, 10:11 AM
#29
I'm still stuck on balance shafts because this is already on our engines and here is how I visualize it:
BS create upward force on both sides of block. Each rotate in opposite direction, so the horizontal forces cancel out but the up/down forces are still there to counter the combustion forces of each cylinder pushing down on crank bearings. These up/down forces reduces engine movements (aka vibrations since it happens at such high frequency) internally.
If we look at BS, we can see that the mass is at the other end of gear, so I'm guessing it's next to cylinder 3 or 4 (I'll try to remember to take a closer look tomorrow). This tells me that the design is to minimize vibrations before it gets to clutch. As for cylinders 1 & 2, maybe that's where harmonic damper comes in. It softens to vibration pulses like what a muffler does to exhaust. If we look from front of engine, cylinders 1 & 2 pushes engine down while BS pushes up, so engine would rotate counterclockwise. Without BS, this pivot would move towards tranny and make things worse.
So, as crankshaft is getting these power stroke pulses, look at where the stress ends up...where it bolts to flywheel which is a spinning gyroscope where it really resists movements.
Can someone confirm if spun crank bearings usually occur at the rear nearest the clutch? If not, I'm back to drawing board with my crayons
BS create upward force on both sides of block. Each rotate in opposite direction, so the horizontal forces cancel out but the up/down forces are still there to counter the combustion forces of each cylinder pushing down on crank bearings. These up/down forces reduces engine movements (aka vibrations since it happens at such high frequency) internally.
If we look at BS, we can see that the mass is at the other end of gear, so I'm guessing it's next to cylinder 3 or 4 (I'll try to remember to take a closer look tomorrow). This tells me that the design is to minimize vibrations before it gets to clutch. As for cylinders 1 & 2, maybe that's where harmonic damper comes in. It softens to vibration pulses like what a muffler does to exhaust. If we look from front of engine, cylinders 1 & 2 pushes engine down while BS pushes up, so engine would rotate counterclockwise. Without BS, this pivot would move towards tranny and make things worse.
So, as crankshaft is getting these power stroke pulses, look at where the stress ends up...where it bolts to flywheel which is a spinning gyroscope where it really resists movements.
Can someone confirm if spun crank bearings usually occur at the rear nearest the clutch? If not, I'm back to drawing board with my crayons
May 3, 2018, 10:32 AM
#30
It's making sense now. The BS reduces up/down vibrations from power strokes while the damper helps to reduce the twisting in the crankshaft.
Removing either just lets all the movements go unchecked.
Without BS, engine pushes down and pivots at flywheel. Without damper, there's more and more twisting inside crankshaft as power moves to flywheel. So I can imagine that without a good damper, we can see cracks from internal twisting. And without BS, we can see cracks from pivoting motions.
I'm putting away my crayons now. I have a brain cramp.
Removing either just lets all the movements go unchecked.
Without BS, engine pushes down and pivots at flywheel. Without damper, there's more and more twisting inside crankshaft as power moves to flywheel. So I can imagine that without a good damper, we can see cracks from internal twisting. And without BS, we can see cracks from pivoting motions.
I'm putting away my crayons now. I have a brain cramp.
Last edited by 2006EvoIXer; May 3, 2018 at 11:13 AM.