Update on crankwalk fix

[NosLaser]

I just wanted to drop a quick line to inform anyone who had previously followed the information I posted about another possible fix for crankwalk. (Before this gets heated, I apologize for making it seem as if it was a conclusive thing, as we were all a bit excited, and things got posted a little pre-maturely. It was merely another idea.) The car in question with the first 'fix' performed has ben up and running for almost a year now with no signs of crankwalk, or any other associated engine or mechanical problems. Just to air out any confusion, the car in question also has a fully built motor, and a rather large (60-1) turbo, PMS, FMIC, web cams, fuel system, etc. so it's not just some grandma driven stocker. I figured after all that heated arguing from months past everyone involved deserved some form of update. Just so everyone knows this is NOT a sales pitch, and is for information purposes only, I will NOT be performing this for people, so don't ask to send your motor down to get the job performed. It's not gonna happen. If you would like, I will explain our findings so you can discuss the process with your local machine shop if interested. I feel this post was very politically correct, so I don't want ANY flames flying around; merely an update.

Regards,

 

[Puke]

Could you or would you please post your finding's/procedure here?

 

[Black95GSX]

Not trying to flame you Nos..... but you also need to realize that not every motor will crankwalk any given time. Furthermore, lately I've heard of more 6 bolts walking then 7 bolts, but that's just me.


Honestly, I'm not going to trust anyone who claims to have a cure for crankwalk, till they have 10-20 cars that they have "fixed" that have over 60k on the motors without them walking (again?). Then, and only then it can be considered a fix........ once again though, this is my opinion.



(For the record... Stock 2g Motor... w/ ACT 2600 (for 30+K now), 12.0 @ 119 .... stock head, stock intake manifold...... and no signs of crankwalk........................................ knock on wood)

 

[NosLaser]

Like I said. It was a simple update. Do I have 30-50-100-or fifty million or however many motors it would take to satisfy a DSM'er as 'proof?' No. Do I care? No. It was an update. I have nothing more to tell you or sell you.

Regards,

 

[mccarlin]

I PM'd you for the Info. i would like it.

thanks alot.

 

[NosLaser]

The cause of crankwalk

Why does crankwalk happen, and what causes it to happy almost solely
on 2G DSM's? To answer this question, you need to look at what makes
the blocks different from eachother, and also look at the actual
metalurgy of the 1G and 2G blocks. From our testing, we have found
that the 1G blocks are actually have a more dense iron content than
the 2G blocks, and are actually stronger. If you notice, on the 1993
and up blocks, they almost seem to have a rib-cage built into them
which is on an engineering level, a very good way to increase
structural integrity. However, something happened in 1995 that
caused Mitsubishi to cheap out on the iron content of the blocks they
were casting. Maybe the R&D of the new car got pricey, and they
needed to cut costs in certain areas or what have you, but those
blocks simply aren't made as strong. The next thing you need to look
at is the thrust area, and that main girdle on the 7 bolt blocks.
Again, from an engineering point of view, a good idea for structural
integrity, and it works great on the 93 and 94 blocks, but again, the
density of the 1995 and up blocks just doesn't quite cut it. This
means you can do one of two things. A. completely change the atomic
composition of the block which would prolly cost you more than your
car did, or B. pick up where Mitsubishi left off, and improve upon
their half-assed design. We chose the latter.

Now, know everyone has been concentrating on oiling, and oil
pressure, and the 2G oil squirters suck, etc. however that idea never
quite held water to me. First off, the oil squirter's main function
is to cool the bottom of the pistons. Secondly, under full throttle,
you are getting upwards of 100psi of oil pressure. 15 pounds of
boost is more than enough air pressure to blow off intercooler pipes
if the clamps are less than perfect, so don't you think 100psi of
liquid pressure would be enough to blow out any bits of grease or
grime in the oil squirters? It doesn't look like a lack of oiling in
my book, from what I have seen on a crankwalked motor. The other
thing I've noticed, is in order to find the cause of crankwalk,
people have dis-assembled blocks, heck, even sliced them in half to
get to the root of the problem. What if the root isn't quite that
deep? What if the cause of crankwalk happens AFTER the short block
begins assembly? If you caught that, read on and I'll elaborate.

Another popular theory of crankwalk is that a heavy pressure plate
causes stress on the crankshaft and literally over time and use will
pull it out of alignment. Those people are actually on the right
track, however something else is failing that is allowing the crank
to be pulled by the pressure plate in the first place. Here comes
our idea. Instead of tearing the block down, and looking at oil
passages, or physically examining the thrust surface, we went the
other way and began assembling, and measuring, and seeing what we
would find. We installed the crank and main girdle, and torqued it
down to factory spec. We then bolted a torque plate on the top of
the block to simulate a cylinder head being bolted down, and we
torqued it to factory spec. What we found ater both had been torqued
was compelling. We measured the thrust area before and after, and
found that it would consistently move .0025-.003" when it had torque
on it! Now, for those who have built and blueprinted an engine
before, .0025-.003" may as well be 2 feet in an area that sees as
much stress and has such a critical job as a thrust bearing. To help
illustrate what is happening here, put your hands together palm to
palm. Now, twist your top hand to the right very slightly and your
bottom hand to the right very slightly. When you "torqued" you
hands, notice they tweaked slightly, and are no longer perfectly
straight. That is what is happening to the 2G block when your
cylinder head is bolted down, and your main girdle is bolted down.
You are causing a condition of pre-mature failure, and things such as
heat, and that heavy pressure plate merely aggravate that existing
problem.

So now we have the root 'cause' of crankwalk, but there's more. This
is going to make sense to those people who have assembled a 4G63
before. When you go to bolt down that main girdle, is there any real
way to line it up perfectly straight? I know I know, the bolt holes
line up, the mains kinda sorta lock into place, yada yada...but are
they going on perfectly straight to the THOUSANDTHS of an inch? If
you can eyeball that, then you are a better man than I. I however,
would put a million dollars on it that there is a measurable
disparity between the tolerances of each main cap, and where it bolts
down. Here's a challenge. Cut the head off a main bolt, and tighten
it down in the hole. Then stick a feeler gauge in there and measure
the clearance between the bolt, and the wall of the bolt hole. Did
you catch it? IF it was going on PERFECTLY sraight, there would be
NO clearance, NO disparity. The bolts would go in much like the
dowels on a flywheel..they would have to be hammered in. Ah ha!
Dowel pins.

A few smart(ly) engineered companies have dowel pinned motors from
the factory; such as Toyota and Nissan. There is a reason for this.
If you are relying on 10 bolts to line up your main girdle, is
essence what you are doing is GUESSING that it's going on straight.
Couple that with your block tweaking and throwing the thrust bearing
off .0025-.003" is like shooting yourself in the foot, and not
learning anything from it. The dowel pins come in to line up that
main girdle PERFECTLY, toleranced to the thousandth of an inch, so
you elliviate any guesswork that may be involved. This is why SOME
motors crankwalk, and SOME do not. Some of the girdles just so
happened to be installed better at the factory, and that is
completely by happenstance and good luck. That's it! However, every
single 2G motor out there does indeed have the capacity to crankwalk,
although some people may never experience it at all.

The Fix

Now that we know what is causing crankwalk, we need to look at how to
fix the problem so it doesn't happen again. First things first, you
must start with a completely flat deck to rule out any possibility of
added 'tweaking' due to an uneven surface (obviously if it goes on un-
evenly, some area will have more pressure applied to them, more
stress, than others.) The block is first cleaned and then decked
true. After that, the main bearing journals are align-honed to
insure we are starting with a perfectly machined bearing surface to
begin with. Then the block needs to be flipped over, and
the 'bottom' end is drilled and machined for dowel pins at 5 points
on the bottom of the block. Matching points are drilled and machined
on the main girdle (obviously, SERIOUSLY close measurements are taken
to ensure everything is perfect..no close, PERFECT.) Just about the
only thing that will withstand than kind of heat is billet steel.
Dowels are formed out of billet steel, and installed into the block.

Obviously at this point, the crank has been inspected, all neccessary
machine work is performed, and it's ready to be installed into the
motor with new main bearings, and new main bolts. The girdle is then
installed on the dowel pins, and hammered down into place. The
dowels are so tight, and fit so well, that you can easily life the
block by it's girdle without any bolts in it. Then the new main
bolts are installed, and torqued to factory spec. The block is
flipped over, and a torque plate is installed to simulate the
cylinder head being bolted down, and then torqued to factory head
bolt specs. The thrust area is measured with everything torqued,
tolerance disparity is recorded, and the block is disassembled. The
crank and bearings are removed, and the process or torqing the torque
plate and main girdle is repeated minus the crank and bearings, and
then the thrust area is re-machined with everything torqued down to
be 100% perfect again. Not close, perfect. The bearings, crank, etc
are all re-installed, and re-measured. The thrust bearing now did
NOT move. Dowel-pinning the main girdle ensured that it went on
perfectly straight every single time which eliminates guesswork and
allows for precise machining.

Regards,

 

[NosLaser]

The above post is a theory ONLY. I do not have the money nor the time nor the resources it would neccessitate to PROVE this thoery. I am not an engineer. I am not a scientist. I am not God. I posted this here so those who asked can have my feedback on said theory. If you flame me for this after I have politely asked for this to be simply information and theory and not grounds for argument, I will hunt you down and feed you your balls. Have a nice day.

Regards,

Edit: Again, this is theory. When I say 'now that we know the cause of crankwalk..' it is simply used subjectively to make the rest of the information make sense. Again, this is not new rocket technology, and the dowel-pinning by itself is not anything revolutionary as it has been done for years. It's simply another angle (machining the thrust area while the torque plate is torqued down, while the main girdle is torqued, after the girdle has been dowelled to ensure it's on perfectly straight) with which to look at the problem of crankwalk. If it helps some of you, great, if not, great.

 

[pasths]

What are the symptons of crankwalk.
I have a ticking noise only when the clutch is pushed in.
As soon as the clutch is out the ticking stops??
Could it be crankwalk??

 

[EclipsingU]

Where is your ticking coming from? If its from the right side of the car near the tranny cover then consider your input shaft bearings. I had one go out on mine and it drove me crazy trying to figure out what it was till my tranny froze up.

Just a little hearsay about crankwalk theory. Someone some where some other time sort of thing I heard that Chrysler picked up the production of the 4G63 in the 2nd gens and mis machined the cranks, and thus began the crankwalking. Anyone else hear this??

Just a FYI for anyone interested. Any car can crankwalk. Just because you have a 1st gen doesn't make you completely safe from it.

 

[BatmanGSX]

I have a 99% flawless cure for crankwalk: step 1) install J-spec 6-bolt, step 2) pray.

Anyone ever notice that 4 out of 5 times 6-bolt crankwalk appears on an engine that has been rebuilt? The way I dealt with possible 6-bolt crankwalk was to get a J-spec and put my own pistons and rods in without even cracking the main bolts off. There are very few people in the world that can properly, beyond all question, assemble a DSM bottom end. Unfortunately most of those people are robots on an assembly line in Japan. Want to keep crankwalk limited to "not your problem"? Get an engine with the crank installed by one of those machines (meaning a J-spec Galant engine).

crankwalk = the thing I worry about least

Just my .02

 

[2Gen_maniac]

hum interesting if this works then there will be a fix for sure.

 

[RACER-X]

Good food for thought Aslan; not a bad theory. Sounds like it could possibly work.

Dose anyone know anything about the new Evo's 4g63 motor? Are there motors exactly the same as our DSM's? I mean aside from the obvious like I know the cams gears, shafts, and oil pump are on oposite sides now.

 

[pickens]

Actually here's a simple yet VERY interesting theory. The 2gs and 1gs get oil for the turbo from different locations. I point that out because here's the theory. Have you noticed that when you upgrade a turbo on a 2g you almost always go w/ a ss oil feed line. That feed line replaces the stock fitting on the oil cooler, BUT that stock fitting is needed for proper oil pressure to the motor. Before you say BS, take a look at the inside of the stock oil line 19mm fitting on the oil cooler. There is a very small orifice that regulates flow/pressure to the turbo. Now take a look at any ss oil feed line kit on the market. That orifice is missing. A ss oil line will allow your turbo to get much more pressure and flow, but the problem comes from the fact that there is a trade off. The oil pressure at idle and low rpm is now reduced to the motor. If you don't believe it, hook up an oil gauge and switch the stock oil feed line to a ss and watch the difference in pressure. Now, this decrease in oil pressure may or may not be the cause of walk, but it would only take a poll to find out. If alot of people have walked and are using ss oil feed lines, then we perhaps can begin to draw a correlation.

 

[badboyr66]

where was this update info found? who is the orgin?

 

[RamenPride]

going from the stock T-25 to a 14B and now 16G using a stock 1G line, I noticed no difference in oil pressure. I have the sender at the oil filter housing and it reads the same.

Originally posted by pickens
If you don't believe it, hook up an oil gauge and switch the stock oil feed line to a ss and watch the difference in pressure. Now, this decrease in oil pressure may or may not be the cause of walk, but it would only take a poll to find out. If alot of people have walked and are using ss oil feed lines, then we perhaps can begin to draw a correlation.

 

[zac83]

Originally posted by pickens
Actually here's a simple yet VERY interesting theory. The 2gs and 1gs get oil for the turbo from different locations. I point that out because here's the theory. Have you noticed that when you upgrade a turbo on a 2g you almost always go w/ a ss oil feed line. That feed line replaces the stock fitting on the oil cooler, BUT that stock fitting is needed for proper oil pressure to the motor. Before you say BS, take a look at the inside of the stock oil line 19mm fitting on the oil cooler. There is a very small orifice that regulates flow/pressure to the turbo. Now take a look at any ss oil feed line kit on the market. That orifice is missing. A ss oil line will allow your turbo to get much more pressure and flow, but the problem comes from the fact that there is a trade off. The oil pressure at idle and low rpm is now reduced to the motor. If you don't believe it, hook up an oil gauge and switch the stock oil feed line to a ss and watch the difference in pressure. Now, this decrease in oil pressure may or may not be the cause of walk, but it would only take a poll to find out. If alot of people have walked and are using ss oil feed lines, then we perhaps can begin to draw a correlation.

I would try to put an oil pressure sending unit up there in the stock 1g location and see if you have good oil pressure there under all conditions. Obviously if youve got good pressure there with the big stainless 2g kit line, then you're doing ok.

 

[the_anti_honda]

ok i dunno if this is kinda off topic? flame me, move my post, delete it, throw a rock at me. i dont care! i am using a SS line and my motor is walking as we speek. also what are all of the signs of walk. just to make sure i didnt spend a whole bunch of money on a 6bolt for no reason. well not no reason i wanted one but dont tell anyone else that like my family they are wondering why i am broke at christmas.

 

[theTuner]

noslaser makes a pretty good point there, anyone know if the evo 7bolts have dowels holding up the gridle? if that's true, damn youve really convinced me

 

[Styler91TSIAWD]

That is a very nice theory on on a crankwalk solution. But people want a cheap fix this is almost a full rebuild on the bottom end of a motor. Pople would just rather put a 6 bolt in there car. Now if you look at the thrus bearing on the block and added to more to the outside to take the prssure off the the one in the center you would have three thrust bearins. I know it would be hard to do since the outside journals only have say a .25 of an inch to have a wall on the outside of a thrust bearing you would have to have special bearins made. But if someone had the money to have these bearins made you could actually replace them while the motor was in yoru car. This would be very cheap and easy to do. Just pull the oile pan and the old bearins while the crank is in the block slip the new bearins on and turn the crank and set the new half moon in its home then put the other half moon in the cap the reinstall. This would be cheap easy fix.

 

[1fast97gsx]

Originally posted by NosLaser
The cause of crankwalk

The Fix

Now that we know what is causing crankwalk, we need to look at how to
fix the problem so it doesn't happen again. First things first, you
must start with a completely flat deck to rule out any possibility of
added 'tweaking' due to an uneven surface (obviously if it goes on un-
evenly, some area will have more pressure applied to them, more
stress, than others.) The block is first cleaned and then decked
true. After that, the main bearing journals are align-honed to
insure we are starting with a perfectly machined bearing surface to
begin with. Then the block needs to be flipped over, and
the 'bottom' end is drilled and machined for dowel pins at 5 points
on the bottom of the block. Matching points are drilled and machined
on the main girdle (obviously, SERIOUSLY close measurements are taken
to ensure everything is perfect..no close, PERFECT.) Just about the
only thing that will withstand than kind of heat is billet steel.
Dowels are formed out of billet steel, and installed into the block.

Obviously at this point, the crank has been inspected, all neccessary
machine work is performed, and it's ready to be installed into the
motor with new main bearings, and new main bolts. The girdle is then
installed on the dowel pins, and hammered down into place. The
dowels are so tight, and fit so well, that you can easily life the
block by it's girdle without any bolts in it. Then the new main
bolts are installed, and torqued to factory spec. The block is
flipped over, and a torque plate is installed to simulate the
cylinder head being bolted down, and then torqued to factory head
bolt specs. The thrust area is measured with everything torqued,
tolerance disparity is recorded, and the block is disassembled. The
crank and bearings are removed, and the process or torqing the torque
plate and main girdle is repeated minus the crank and bearings, and
then the thrust area is re-machined with everything torqued down to
be 100% perfect again. Not close, perfect. The bearings, crank, etc
are all re-installed, and re-measured. The thrust bearing now did
NOT move. Dowel-pinning the main girdle ensured that it went on
perfectly straight every single time which eliminates guesswork and
allows for precise machining.

Regards,

isn't that what these basically do??

 

[NosLaser]

1fast97gsx,

You ask the same question everybody asks. Perhaps if you read the entire thing, and didn't focus on two words (dowel and alignment) you would see what makes this different. First off, those dowels aren't really dowels; simply sleeves that take up the slack in the existing bolt holes. It's a good and cheap idea which is definately worth the money. The dowels used in 'the fix' are actual billet machined dowels with receiver holes drilled into the main girdle.

But that isn't even the point! That is only a small part of the equation. The focal point is actually having the block align-honed WHILE the torque plate is torqued down on the head, and WHILE the main girdle (already properly aligned) is torqued and mounted on the bottom of the block. This is what had set this idea apart from the others, but nobody used their reading comprehension skills to realize it, so the idea simply got flamed. The problem is machine shops align hone the block without any torque on it. When you bolt the main girdle down, and then bolt the cylinder head down, the thrust bearing is thrown out of alignment. The reason for this in my theory is the metalurgy of the block. Mitsu cheaped out on the actual material used when casting the block, and I believe this has been proven through other shop's individual tests. Combine billet machined dowels, with perfectly machined receiver holes, the torque plate being torqued down, the main girdle being torqued down, and THEN align-honing the block is what 'the fix' was all about. NOT just dowel pins. Again, if you haven't picked up on it yet, then you really need to read it again. NO, it is NOT just dowel pins. Did you see it that time? Okay, just making sure. Not just dowel pins. We've performed 'the fix' on several cars down here, and not a single one crankwalked yet, and they are driven daily, and raced constantly. I'm not into DSM's at the present time, so I really don't give a shit if you guys agree/disagree. It was simply information sharing, and that is that. If you want to use the information, more power to you. Take it to a machinist who knows what he is doing, explain the problem of crankwalk, and explain the fix, (better yet, print this out so you don't butcher the hell out of it like most DSM'ers do) and see if he thinks it makes sense. I have nothing further to tell you or sell you.

Regards,

 

[1fast97gsx]

well of course if everything was aligned.... when mitsu first assembles the block everything SHOULD be aligned .. so had they used those inserts it would still be aligned 60,000 miles down the road. The dowel pins and inserts / sleeves do the same thing ... the alignment is obviously something a machine shop has to do that has nothing to do with either of those. I was just saying from your explanation you are basically saying : have everything aligned, put in the inserts ( or dowels ... same thing ) and torque it all down ( using a torque plate of course ) properly and most likely no crankwalk.

 

[NosLaser]

...But people want a cheap fix this is almost a full rebuild on the bottom end of a motor. Pople would just rather put a 6 bolt in there car....

You know what? I can't save the world bro. I can only offer additional information. We live in a society of immediacy. People want it done Good, Fast, and Cheap. I've always said, you can have it good and fast, but it won't be cheap. You can have it fast and cheap, but it won't be good. You can have it good and cheap, but your car won't be fast.

This machining process is cheaper than buying a 6 bolt and having it installed, however you are right, it isn't cheap (probably retails around 6-700 bux.) But you do have one advantage over the 6 bolts which is the full main girdle rather than cheeseball little main caps. The girdle design *is* much better, just flawed because the manufacturer cheaped out. Huh? Uh oh! Look what happens when you cheap out!! Maybe that should be a lesson to you and your 'cheap fix.' Just food for thought.

Regards,

 

[NosLaser]

Originally posted by 1fast97gsx
well of course if everything was aligned.... when mitsu first assembles the block everything SHOULD be aligned .. so had they used those inserts it would still be aligned 60,000 miles down the road. The dowel pins and inserts / sleeves do the same thing ... the alignment is obviously something a machine shop has to do that has nothing to do with either of those. I was just saying from your explanation you are basically saying : have everything aligned, put in the inserts ( or dowels ... same thing ) and torque it all down ( using a torque plate of course ) properly and most likely no crankwalk.

No, you actually do not get it yet. The top half of the block tweaks just like the bottom does! When you torque down the cylinder head, it mis-aligns the thrust area; it's not just the girdle that gets knocked out of shape. And you are in for a world of disappointment if you think Mitsu machines these blocks with torque on the deck and the mains. They are cheap computerized castings, and are then assembled by computer at a sprinters pace. And no, I did NOT say align the girdle with dowels and then torque the head on. I said, have a torque plate already torqued down, have the now dowel'ed main girdle already torqued down, and THEN machine the thrust area. They are not even close to the same thing. And if you think those sleeves take the place of billet machined press-fit dowels, you really have another thing coming.

Regards,

 

[1fast97gsx]

I see the concept however I do not believe our blocks are really that weak. Why are we able to run 20+ pounds of boost if the block will stretch and deform and what not then?