I didn't plan on writing out this much, but it took a little more explaining than I thought. Please note, these are just my opinions and I am just stating the obvious facts; along with throwing some knowledge out there about the MBCAD kit..Here it goes.
So, for you people that don't know what this is - it's the Main Bearing Cap Alignment Dowel Kit (MBCAD Kit). Since I'm in the process of re-building my 7-bolt, I will be using these. Main Bearing Cap Alignment Dowel (MBCAD) Kit
Here's the way I see it...When you're putting the bottom-end backtogether, when you put the bearing cradle in the block and throw the studs in, there is just enough play between the cradle and studs, not visible to the naked eye. Even when torqued, everything seems secure and tight, but is it? For the time being, yes. Until you get everything back together and actually start driving. What happens? Shift after shift after shift through all of the gears day after day. Each time you're shifting gears, you're of course using the clutch. Each time you disengage the clutch, you're putting all of that pressure on the most critical part of the motor...The crank.
Now, that 'tight and secure' bearing cradle that has brand new bearings, studs, etc is/could be possibly shifting from the force of the clutch, especially during hard driving.
What about when you're starting that dry motor with the clutch in? Dry bearings, no oil pressure, a sloppy bearing cradle, and all of that force pushing everything towards the other side of the motor.
Sound like all of the above can cause premature thrust bearing failure? I'd say yes.
For those of you who don't know, the MBCAD kit is suppose to fix this problem. These dowels go in between the bearing cradle and block during assembly, and are designed for use with ARP main studs. They're suppose to give you a 100% secure, tight fit. Keeping everything aligned. During assembly and during driving. I wish Mitsu would have used something like these from the start, because there's obviously a flaw.
I know there have been hundreds of theories about our problems with pre-mature thrust bearing failure, but no one has pin-pointed it. Then there are those who say it's all a myth. HOW is it a myth? Because it didn't happen to you YET? It's a bearing. You have a heavy crank spinning so fast, there's this thing called friction. Friction causes heat and also wears things down. (Take a wrench and hold it to a grinder for 10 minutes. What's it going to do? Get hot, and wear down until it tears through).
Premature bearing failure can happen to ANY motor, NOT just DSM motors. And as for doing a 6-bolt swap into a 2g to FIX crankwalk, this is also BS. I've seen just as many 6 bolts walk just as 7-bolts. IMO the swap is a waste of time, and most people usually run into other problems because they can't do the wiring correctly or they do a half-ass job. But again, that's just my opinion.
Anyway, here's a better way to see it. How many of those half-ass mechanics went to replace the clutch assembly, and didn't bother putting those dowels back in between the motor and transmission? Why wouldn't they put them back in?
I'd say it's because 50% of some people just didn't realize they fell out during transmission removal. The other 50% just didn't want to have the hassle of trying to get the transmission on the dowels because "they just get in the way".
Anyone ever read articles about people blowing through clutches like it's their job? This would be why. Most of the time, the dowels aren't there. They put dowels there for a reason, use them. And IF the dowels are there, and they still keep blowing out clutches, then obviously the problem lies elsewhere. Either mechanically or poor mechanic skills.
Which brings me to my next idea...Most people never see "crankwalk", but for those who do, it has usually happened around 60,000miles. Some around 90, some at 120, and so on (172,xxx for me).
Then they get frustrated, pull the motor out, and "rebuild" it in ONE day. People are too lazy to take measurements (or just think a motor can go back together just the same as it came apart). They get the motor back in, drive it, and what happens?
1. Spin a bearing (failure to check bearing clearance or debris in the block)
2. Premature thrust bearing failure (except this time a few thousand miles down the road - again, failure to check clearance or not properly align it)
3. Ring problems (wrong end gap, upside-down or mis-aligned rings)
4. Forgot to torque something to spec
5. Leak oil
6. Lock a pump up from neglecting to PRIME it
7. Have issues with timing
8. Etc
My point is, you can't just tear a motor down, put new bearings/seals/bolts/gaskets/rings in it and throw it back together. It just doesn't work that way. Well, it does, but how long is it going to last? One start, a mile, a hundred miles, a thousand? Take the engine to a machine shop to get cleaned up and have all of the clearances checked. Get crank work done if needed. Deck the block/head, etc. This is another reason why people have so many bearing problems. A lot of sloppy mecahnics just don't take measurements (I'm not saying everyone, just a lot of people and I'm sure some of you will agree with me).
I know quite a few shitty DSM "mechanics", and hell, if they rebuilt a lawn mower engine, I can almost GUARENTEE you it would crankwalk from shitty rebuilding skills. Hell I bet you if Mitsu made a turbo lawn mower, there'd be a lot of walking lawn mower cranks
My point is, I just hate seeing a perfectly good motor go to waste due to lack of skills or just plain laziness. By no means am I saying anyone on here can't build a motor, I'm just stating from what I have seen in the past. And this article was to help explain the MBCAD kit because IMO it's a great, cheap investment.
I contacted machv about this kit, and was told that they have never received any e-mails or phone calls about a crank walking when using the MBCAD. After being told this and doing some homework on it, I won't hesitate to order these when I go to rebuild my 7-bolt.
So, for you people that don't know what this is - it's the Main Bearing Cap Alignment Dowel Kit (MBCAD Kit). Since I'm in the process of re-building my 7-bolt, I will be using these. Main Bearing Cap Alignment Dowel (MBCAD) Kit
Here's the way I see it...When you're putting the bottom-end backtogether, when you put the bearing cradle in the block and throw the studs in, there is just enough play between the cradle and studs, not visible to the naked eye. Even when torqued, everything seems secure and tight, but is it? For the time being, yes. Until you get everything back together and actually start driving. What happens? Shift after shift after shift through all of the gears day after day. Each time you're shifting gears, you're of course using the clutch. Each time you disengage the clutch, you're putting all of that pressure on the most critical part of the motor...The crank.
Now, that 'tight and secure' bearing cradle that has brand new bearings, studs, etc is/could be possibly shifting from the force of the clutch, especially during hard driving.
What about when you're starting that dry motor with the clutch in? Dry bearings, no oil pressure, a sloppy bearing cradle, and all of that force pushing everything towards the other side of the motor.
Sound like all of the above can cause premature thrust bearing failure? I'd say yes.
For those of you who don't know, the MBCAD kit is suppose to fix this problem. These dowels go in between the bearing cradle and block during assembly, and are designed for use with ARP main studs. They're suppose to give you a 100% secure, tight fit. Keeping everything aligned. During assembly and during driving. I wish Mitsu would have used something like these from the start, because there's obviously a flaw.
I know there have been hundreds of theories about our problems with pre-mature thrust bearing failure, but no one has pin-pointed it. Then there are those who say it's all a myth. HOW is it a myth? Because it didn't happen to you YET? It's a bearing. You have a heavy crank spinning so fast, there's this thing called friction. Friction causes heat and also wears things down. (Take a wrench and hold it to a grinder for 10 minutes. What's it going to do? Get hot, and wear down until it tears through).
Premature bearing failure can happen to ANY motor, NOT just DSM motors. And as for doing a 6-bolt swap into a 2g to FIX crankwalk, this is also BS. I've seen just as many 6 bolts walk just as 7-bolts. IMO the swap is a waste of time, and most people usually run into other problems because they can't do the wiring correctly or they do a half-ass job. But again, that's just my opinion.
Anyway, here's a better way to see it. How many of those half-ass mechanics went to replace the clutch assembly, and didn't bother putting those dowels back in between the motor and transmission? Why wouldn't they put them back in?
I'd say it's because 50% of some people just didn't realize they fell out during transmission removal. The other 50% just didn't want to have the hassle of trying to get the transmission on the dowels because "they just get in the way".
Anyone ever read articles about people blowing through clutches like it's their job? This would be why. Most of the time, the dowels aren't there. They put dowels there for a reason, use them. And IF the dowels are there, and they still keep blowing out clutches, then obviously the problem lies elsewhere. Either mechanically or poor mechanic skills.
Which brings me to my next idea...Most people never see "crankwalk", but for those who do, it has usually happened around 60,000miles. Some around 90, some at 120, and so on (172,xxx for me).
Then they get frustrated, pull the motor out, and "rebuild" it in ONE day. People are too lazy to take measurements (or just think a motor can go back together just the same as it came apart). They get the motor back in, drive it, and what happens?
1. Spin a bearing (failure to check bearing clearance or debris in the block)
2. Premature thrust bearing failure (except this time a few thousand miles down the road - again, failure to check clearance or not properly align it)
3. Ring problems (wrong end gap, upside-down or mis-aligned rings)
4. Forgot to torque something to spec
5. Leak oil
6. Lock a pump up from neglecting to PRIME it
7. Have issues with timing
8. Etc
My point is, you can't just tear a motor down, put new bearings/seals/bolts/gaskets/rings in it and throw it back together. It just doesn't work that way. Well, it does, but how long is it going to last? One start, a mile, a hundred miles, a thousand? Take the engine to a machine shop to get cleaned up and have all of the clearances checked. Get crank work done if needed. Deck the block/head, etc. This is another reason why people have so many bearing problems. A lot of sloppy mecahnics just don't take measurements (I'm not saying everyone, just a lot of people and I'm sure some of you will agree with me).
I know quite a few shitty DSM "mechanics", and hell, if they rebuilt a lawn mower engine, I can almost GUARENTEE you it would crankwalk from shitty rebuilding skills. Hell I bet you if Mitsu made a turbo lawn mower, there'd be a lot of walking lawn mower cranks
My point is, I just hate seeing a perfectly good motor go to waste due to lack of skills or just plain laziness. By no means am I saying anyone on here can't build a motor, I'm just stating from what I have seen in the past. And this article was to help explain the MBCAD kit because IMO it's a great, cheap investment.
I contacted machv about this kit, and was told that they have never received any e-mails or phone calls about a crank walking when using the MBCAD. After being told this and doing some homework on it, I won't hesitate to order these when I go to rebuild my 7-bolt.
