4g63's are famous for hosing crankshaft thrust bearings. This video illustrates the process of how to check the thrust bearing clearance whether the motor's in the car or not. Of course in my case the motor's on a stand for this video. Lucky for me!
In cases where the engine is still in the car, the same procedures can be used so long as the indicator is attached to the engine block. The plunger can be set up touching either the inside of the crank pulley or by removing the clutch cover plate and contacting the flywheel.
What the thrust bearing does, is prevent the crankshaft from having lateral movement in the main bearings. If a crankshaft develops excessive movement here, clutch engagement and hydraulic problems will begin showing up, followed shortly thereafter by catastrophic failure of main bearings, rod bearings, connecting rod failures, oil pressure problems, or even broken blocks, crankshafts and rods in extreme cases. It's important that every 4g63 turbo engine is within spec on this measurement.
When the crankshaft aggressively wears through the thrust bearing developing lateral play, this is called "crankwalk". On some block castings, replacing the bearings will NOT fix the problem. An engine block that is prone to crankwalking can not be fixed. The only option in these cases is to replace the shortblock and rotating assembly with new or used parts that are stronger than the one you've unfortunately encountered. For the 2g guys, the best option for repairing this problem is to remove the 7-bolt turbo shortblock your car came with and replace it with a 6-bolt from a 89-92.5 production date turbo DSM. Non-turbo blocks CAN be used; however, the block will not have oil squirters that aim towards the back of the pistons. That stream of oil aides lubrication to the wrist pins, cylinder bores, and somewhat cools the pistons. All good things on a turbo setup. Aside from that difference, there are no other differences between the non-turbo and turbo blocks. The pistons and thus the compression ratios are different, but that's it. Oil squirters can be machined into the main galleries of a non-turbo block, but it's more trouble than it's worth unless you can't find a turbo block.
There are tons of differing theories about what causes crankwalk. Nearly all of them are plausible and logical arguments. I will not get into those debates in this video in order to focus on procedures for testing and replacement. Please feel free to google "crankwalk 4g63" and read the volumes of information available already. The arguments and gathered data are older than the Eclipse itself and in abundant supply on the internets. Magnus, RRE, VFAQ, and many other parts vendors have lengthy write-ups on their own research and development. The bottom line is that the 6-bolt shortblocks are LESS likely to suffer from this.
Next time you see someone with a video that looks like it was shot with a potato asking "does this sound like crankwalk", you can send them this video. There's a reason for every noise, rather than focus on the sound, focus on eliminating the real problem. KNOW if it's out of spec.
7-Bolt Shortblock Failure - Full Diagnosis
If you are your own mechanic, there is no more important character trait
worthy of development than the ability to own your mistakes. That's where
the line is drawn between good mechanics and bad mechanics. It's not the
failures but how they deal with them that measures their ability.
In short, it's not easy to admit you did something wrong or were negligent.
But if you don't own it and talk about it, it doesn't get fixed, and
nothing positive can come from it. It was my quest to overcome my clutch
issue that lead to the creation of a video. That video is the textbook
perfect guide for how to correctly install a DSM transmission.
Crankwalk as described is caused by a casting defect. This was not a
defect. This was preventable. A lot of people would find something like
this and not tell anyone out of embarrassment. I'm not ashamed. It's my
fault. I got good use out of this engine and it was tough enough to make
it 48K miles since the last rebuild despite my abuse. I'm here to tell you
if you bought a used car that's had its clutch replaced, or if you ever pay
someone else to do it... make sure it has this bolt. It's stashed away
between the starter and the transfer case, so it's hard to see. Make sure
all of your bell housing bolts are torqued properly because fastener
problems can destroy your shortblock, clutch and transmission. If your car
fails because of a mis-aligned transmission, you have no reason to blame
It wasn't until I bought my next AWD car that I discovered there was a
smaller bolt on the other side of the block. I destroyed 3 transmissions
in the GSX first. With the damage already done to my crankshaft, I then
lost a shortblock. It's an ounce of prevention that's worth metric tons on
your bank account.
Grade 10 M8x60 bell housing bolt = MD706012. It gets 22-25'lbs of torque.
Owning my mistake permits me to learn from it through con$equence$, and
never repeat it. What good would it have done anyone else for me to learn
this lesson and not share it? That's why I'm providing this video to all
of you. Sharing it can perhaps help someone else avoid this costly
mistake. This is the final chapter for my 7-bolt, and this book is going
back on the shelf.
Here are some valuable resources if you're trying to read bearing damage:
And of course, now that I've covered the complete oil system, transmission
and driveshaft series of videos, you now have all the tools necessary to
ensure your 4g63 lasts a very long time. Whether the casting defect
exists?... or it's all caused by a bolt, or the harmonics, or whatever...
Sure, crankwalk exists and it's horrible. But with the small amount of
movement required for your crankshaft before it contacts the block isn't
far enough to make your clutch drop to the floor when you turn. You'd be
hearing woodpeckers and jackhammers on the crank long before that clutch
pedal would fall to the floor. Some people are going to hate on me for
saying that. That's fine. I believe all of the people who experienced the
clutch pedal issues had fastener problems on their bell housing.
DSMs get a bad reputation for this but we can change that. Crankwalk is
never the cause of your engine failure. Crankwalk is always a symptom of
the real problem. It's your disease that makes you deny it's your fault.
You've got the 'itis. DSM-itis.
Whenever you dig deeper, you'll discover what applied all of those thrust
loads to your crankshaft to begin with, and it's not going to be a casting
defect that moves your crank .101". Mine only went .014", but all of the
same parts failed.
PLEASE tell me in the comments if you find this bolt is missing from your
Blueprint 103 - Connecting Rods
Connecting rods are the crux of the engine. They're responsible for
carrying the force of the explosions that occur in the combustion chamber
and using it to turn the crankshaft. Oil clearance specifications of the
"big end" and "small end" are crucial to maintaining consistent oil
In this video we take 3 measurements:
Rod Journal (also called Crank Pin) Diameters
"Big End" Bore diameter
Using the Journal diameters and the "Big End" Bores, you can calculate your
oil clearances of each bearing. The process is illustrated here. Anyone
rebuilding an engine who doesn't know its history should check all of these
clearances whether or not they're re-using the rods. If the crank,
bearings or connecting rods are going to be replaced, it's imperative that
you measure the new parts as well to ensure they're in spec.
CRANKWALKED? 7-bolt teardown 1080HD
Audio track by RojoDelChocolate.
Here's the 48,000 mile-old 7-bolt I blew up summer 2011 after over 150 drag
passes, a half dozen Dyno sessions, 4 transmissions,
3 clutches and 10 years of hard all-weather use.
Now this is a story all about how
My bearings got flipped-turned upside down
And I'd like to take a minute just sit right there
And tell you how I used to mix and burn my gas and my air.
In RVA suburbs born and raised
On the dragstrip is where I spent most of my days
Chillin out, maxin, relaxing all cool,
And all shooting some BS outside with my tools
When a couple of guys who were up to no good
Started running races in my neighborhood
I heard one little knock and my rods got scared
And said "You put it in the garage until you figure out where..."
I Begged and pleaded that it not be that way,
But it didn't want to start and run another day.
I kissed it goodbye, because the motor punched its ticket
I got out my camera, said "I might as well kick it."
Crankwalk yo this is bad
Drinking metal shavings from an oil pan.
Is this what the rumor of crankwalk is like?
Hmm this won't be alright
But wait I heard knocking, grinding and all that
Is this the type of failure that should happen to this cool cat?
I don't think so, I'll see when I get there
I hope they're prepared for this video I share.
Well I pulled all the bolts and when I came out
There were chunks in my fluids in the pan and they drained out
I aint trying to get depressed cause I got all my spares out.
I sprang into action like lightning disassembled
I whistled while I worked and my hands never trembled
The 7-bolt was FRESH with the shine like a mirror
If anything I can say this bling was rare
What I saw inside the engine stained my underwear.
I turned off the air compressor 'bout 7 or 8
And I yelled to crankcase "Yo holmes, smell ya later"
I looked at my internals they were finally there
To sit on my workbench and stink up the air.
Cylinder Head 105 - Valve Job Basics
Valves not sealing? Valves not bent? This is how you fix that problem.
In this video I outline the basic valve job procedure. Cleaning the
valves, cleaning the seats, cleaning the combustion chamber and lapping the
valves in to make a better seal.
Here I cover the process start-to-finish. It's the same exact process for
pretty much all non-rotary combustion engines. It takes patience and
perseverance to do this job, but anyone can do it. Reference your service
manual for measurements and service limits. Everything else that's not in
your service manual is in this video.
I apologize for not having broken busted crap to work with in this video.
It's more beneficial to all of you when bad fortune falls on me because it
gets well documented, and many people watching these videos are looking for
answers. If you have bent valves, you will discover it quickly once you
chuck one up in the drill. You'll see the face of the valve wobble around
while it spins. You'll see evidence of this damage on the valve seat. If
it's bad, you may see damage on the valve guides in the form of cracks or
missing pieces where the valve guides protrude through the head ports.
Give all that stuff a good visual inspection. ...and if you doubt yourself,
never hesitate to get a second opinion or consult a machine shop. They
will have access to expensive tools that you wont find in your average
6&7-Bolt 4g63 Front Case & Oil Pump Rebuild
Here we disassemble, clean, inspect and rebuild both popular 4g63 front
cases. This is not difficult, you just need to know what to look for.
Something else that happens in this video is the analysis of one of the
factors that caused my 7-bolt engine to fail. It wasn't the only cause,
and we'll talk about that later, but left to its own devices and without
the other contributing factors, it would have been the only cause.
Blueprint 101 - Using Micrometers, Calipers, & Bore Gauges
If you're going to rebuild an engine, this video is required material.
None of your measurements mean anything if they're not accurate. I
illustrate the calibration and use of 3 major tools needed for taking
measurements, and a brief demonstration of how they work. These are by no
means the ONLY ways to use or calibrate these tools. This is simply the
method I will employ to measure parts in later videos so this instruction
doesn't distract from their intended messages. Even if you're familiar
with these tools, you may find something useful here, or even be able to
correct me and my rusty skills.
Blueprint 104 - The Crankshaft
It's important to know what you've got even before dealing with the
machinist. If you want to inspect a crankshaft, this is how you do it. I
detail the process of removing the crank and what to measure. All
specifications in this video are illustrated with a 6-bolt 4g63 turbo block, but are all actually the same for
7-bolt engines with the exception of the rod widths.
6-bolt 4g63 shortblock rebuild parts
I'm saying it right up front. This video goes above and beyond shortblock
rebuild parts for a reason. Read on... The first part is stern, the last
part is happy.
Nobody in their right, left, forward or reverse minds puts a 23-year-old
4g63 engine back together with 100% OEM parts. Nobody's shooting for that
good ol' stock 190hp feeling with a DSM drivetrain. Nobody. Not unless
they've got something to prove.
I am putting a 7-bolt head on a 6-bolt block. So with that said, I show
several over-the-top internal parts that are and are not related to the
short block itself. I show cams and valve springs which only matter for
head work. Not part of the short block. Nobody makes an engine gasket kit
with all the parts mixed and matched to do this. So what people have to do
is order both kits, or order all the individual parts separately like I am
It's at this stage you are working with a machine shop to return your old
worn-out block to the specs you've chosen to follow, and you need these
cylinder head parts at this stage of the game to do it right. These parts
making an appearance in this video show 3 things... 1) I am not aiming for
a stock build 2) Now is the time to have your cam and valve springs if
you're going to make any changes to the head. 3) these gaskets, seals,
pins, bolts and bearings are things you will need no matter what it is
you're building if it's a 6-bolt block. When I do the head series, I will
be showing modifications and parts to rebuild and make a 7-bolt head fit a
This video assumes you disassembled a running or freshly-broken engine and
that YOU HAVE ALL THE BOLTS, NUTS, WASHERS, and HARD PARTS of the motor
that it needs, bagged and tagged like was demonstrated in the
"Crankwalked?" video. You've watched me clean and inspect valves, lifters,
rockers, crankshafts, rods, etc. I don't need my turbo, hoses, vacuum lines or anything like that
yet, and they likely won't be for a MHI turbo anyway. This video focuses on the gaskets,
seals, bearings, consumable and disposable parts that you should replace
for the shortblock only. My old trusty 6-bolt front case is coming up in a
future video, getting refurbished and rebuilt, and ssembling a shortblock
doesn't require having timing components yet. The head gasket will
probably get its very own video just like the front case.
As you can see, I have very big plans with this upcoming series. We've hit
the 200's on engine stuff. It's a milestone.
For you 7-bolt guys... bah! I know this is all 6-bolt part numbers. Some
parts are interchangeable but I didn't make it clear which ones are in this
video. Don't worry, you will need these part numbers eventually (I hope
that was a joke). But if you wait long enough, perhaps I'll be
re-assembling a 7-bolt again? Here comes the first bit of good news...
The reason the "Crankwalked?" video had a question mark in the title is
because I wanted to see others' comments about it. Gain a consensus.
There are so many different opinions about shortblock failures on the 2g
cars that I didn't want to take sides with such an entertaining video. But
it's not crankwalked. What you see is rod bearing failure as a result of
torsional stress on the crankshaft. It was caused by a catastrophic clutch
failure. The thrust bearing was .014", and crankwalk cars that fail from
crankwalk are usually around .075"-.150". My thrust bearing was beat to
death as my old 6-puck fragged. All the fail was initiated by the
drivetrain, and the drivetrain problem was a fail by yours truly that had
repeated several times prior to me making videos about it and getting it
right. It's my fault for not catching it, but when I discovered it, the
drivetrain series was born. So my 7-bolt crank is trashed, but the mains
are fine. New bearings and a crank would fix its thrust measurements and I
may just rebuild it for the sake of a video someday.
Now comes the really good news. My brother is working with me to build a
website. There will be tech links and things that simply can't be
delivered on YouTube. Not in a practical and effective way anyway. Things
like schedules, projects and mod lists, parts lists, bolt lists, torque
specifications, printable worksheets for blueprinting, the parts I used to
make my fuel injector cleaner... stuff my viewers need or ask for. Soon
you'll know where to find it. I need to learn how to maintain it, but I'm
a good student. Still, these things take time, and I haven't yet wrapped
my own brain around its potential. I'm putting it out there for you guys
because you deserve it. I'm simply astonished at how the channel has
grown, and I feel the need to give back.
Blueprint 106 - Cylinder Bore Inspection
We're close to the end of the 100-level series. In this video I show you
how to measure the cylinder bores using 2 different tools. I compare the
results and illustrate what to look for to determine whether or not your
engine is in-spec.
The block I'm using is a 6-bolt turbo
4g63 from early '92. It has 150,000 miles and this video also serves as a
testimony for the durability of Mitsubishi's cast-iron solid-decked Sirius
I engines. This engine will be cut for a new set of pistons, so these
measurements are needed to determine what size pistons I need to get.
.030" is as far overbored as you should ever take a 4g63. Boring larger
than that will take too much off the side clearances between the cylinder
walls and result in compromised strength from hot spots. The only time
you'll ever need to cut a bigger hole is when an imperfection prevents you
from using the pistons you have, or if you're changing to a larger piston.
If you cut the block to its service limit, you have no room to fix an
imperfection should one develop... so it's best to cut as little as you can
get away with. Boring a cylinder .020" over does not significantly
increase its displacement.
Cylinder Head 106 - Casting & Porting Tech
No really guys, what can I type here? I just went on for 18 minutes
without shutting up. I apologize for deviating from my normal format, but
we're almost there...
...when I port a head, there will be no voiceover, and it will be a
6-bolt 4g63 Crankshaft Chamfer & Oil Clearances
These are some things you need to think about during your build. Some
engines don't have any chamfer on oiled journals whatsoever. All equipment
like that can benefit from at least a light chamfer like the one that's on
a stock Mitsubishi crank shown in this video.
When you Chamfer an oil passage, you create a low-pressure zone where the
edges of the oil passage lift away from the bearing as it passes over it.
The principles of fluid dynamics dictate that if there wasn't an available
substance to displace that low pressure zone (in this scenario, there is an
oil supply), cavitation might occur. If we were talking about
aerodynamics, the effect would be lift.
An extremely-advanced or leading chamfer is actually capable of sucking oil
off of a flat bearing, whereas a trailing chamfer vacuums oil out of a
gallery and does a better job of spreading it around.
The modification that was performed here is intended to increase oil flow
to the mains and the rods. It's mentioned in the video that I'm setting up
my rod oil clearances on the looser side of spec. This will decrease block
oil pressure because more oil will be able to leak past the fillets of the
crankshaft and back to the pan.
But there's another modification being performed. A balance shaft
elimination. There will be lots of debate about this in the coming videos
as that transpires, but one of the side-affects of doing a BSE is increased
oil pressure. With several internal oil holes plugged off inside the
block, I will have a spike in oil pressure. I had my chamfers cut straight
in order to offer the largest practical surface area to apply oil to the
mains and rods. My intention is to relieve some of this oil flow that
doesn't have anywhere else to go. With the added flow, the straight
chamfer is actually beneficial to the mains, allowing them to intake more
oil as well as to spread more of it on the flats below the grooved upper
The animations illustrate this completely. They were created by
yours-truly. I know the oil hole on the mains is on the wrong side. It
was too much work to fix, but they get the point across. Don't laugh at
them any harder than I did.
Cylinder Head 102 - Hydro Test Valves
If you noticed a drop in compression on one cylinder, and pouring a cap of
oil through the spark plug holes didn't fix it, then it's likely you
experienced a leaky valve or a burnt valve seat. What this test does is
show you where it was leaking. Typically it takes a valve job to repair,
but this can also occur on a freshly-machined head if any work was done
improperly or out-of-center.
I'm using tap water for the test because both cylinder heads I'm testing
will receive extensive machine work and cleaning before being re-used. If
you were to do this test on a freshly-machined head, you'd want to use
deionized water as it contains none of the salts (sodium, chlorine, etc...)
that would leave deposits and corrode metal parts.
Cylinder Head 108 - 4g63 Rockers
Cleaning and inspection of 4g63 rocker arms. Part 8 of the head series,
and probably the easiest one yet to either watch or perform. No precision
measurements required, no disassembly or special tools required. If you've
got an air compressor and a pick, and a little bit of patience, you can do
this part of the job without expending any major effort.
This is one of those things that during the course of your build, you can
do unconsciously. You just need to soak them, poke them, and inspect them.
In this video I show you how.
Some parts of the wheel Mitsubishi didn't want to re-invent each time they
developed a new motor. These rocker arms are prevalent in millions of
Mitsubishi, Plymouth, Chrysler, Dodge, Eagle, Hyundai and even some Kia
engines. A good rule of thumb is... everything with a 4g6x DOHC or 6g72
and 6g74 engine uses these rocker arms. From 4x4's to economy cars, these
parts are everywhere. You just need to know what cars they're in and you
can harvest a full set for a fraction of the cost of one of these things
new. If you watch this video, you'll see how to pick a winner.
Check this link for 6g7x donor cars.
I didn't really want to see any of my rockers damaged, but really I'm lucky
some were because it gave me an opportunity to show you some bad ones.
Mine suffered from oil starvation caused by rod bearing failures. That
loss of oil pressure in addition to oil passages being blocked quickly took
a toll. Just 5000 miles earlier I changed to 3g lifters and they were all
fine, so this happened quickly. HKS 264/272 cams didn't help anything once
the oil supply was compromised, but this was discovered before a more
expensive failure in the valvetrain could develop.
Remember that sharing is caring. Hit the like and subscribe buttons
because YouTube shows all of us a little more love when you do. :)
Blueprint 108 - inspect the deck
There's a reason why there are no subtitled specifications in this video
for the block. It's because they don't exist in either service manual, 1g
or 2g. You're not supposed to remove material from a block on the deck
surface because it has ill effects on parts of the combustion chamber
geometry, and alters your compression ratio. It can be done intentionally
in some cases for a desired side-affect, but if you have to deck a 4g63
head, it would be advised to use a thicker head gasket. The Mitsubishi
Multi-Layered-Steel or MLS gasket is slightly thicker than the OEM
composite gasket. Also, HKS, Power Enterprise, Cometic, and other
performance brands all make MLS gaskets that are .065 and thicker.
THERE IS ONE ERROR IN THE VIDEO. I said a block with .002" warpage is
junk. I was completely and totally wrong. While I don't wish to spread
misinformation, I don't think it's a big enough error to warrant re-editing
this video. I just wasn't paying attention. .002" warpage on a cylinder
head is the service limit before it needs machining. I meant to say
.02"... or two HUNDREDTHS (not thousandths) of an inch.
...and here's my justification...
A warped block to me is junk either way even if its minimal because your
MLS gasket will never seal unless both the head and the block are perfectly
flat. Trust your machine shop to get the values for how much is taken off,
and buy the correct thickness gasket for your machine work.
A factory head gasket (composite) is .051"
The MLS Mitsubishi gasket is available in the stock .051 and a .062"
Cometic makes gaskets up to .072"
There are some brands that go as high as .127", but I'd have thrown both
the block and head away long before then.