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.
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.
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.
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.
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.
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
Blueprint 105 - Main Bearing Oil Clearances
In this episode we measure the bores for the crankshaft and calculate the
oil clearances based off of information gathered in the previous video. If
you subtract the diameter of the crankshaft from the bore diameter, you end
up with your oil clearances.
If this were an assembly with new parts, I would have also paid close
attention to bearing measurements 45° off-centerline just to make sure the
bearings aren't pinched. I would also have double-checked the clearances
using Plastigage. But what I'm doing here is just getting baselines prior
If you're doing a dry assembly like this, DO NOT ROTATE THE CRANKSHAFT.
Without oil, there is nothing preventing it from being damaged.
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.
Trans & Clutch 4 - Installing The Clutch
What you wanted to know about clutches but were afraid to ask.
I'm putting a ACT MB1-XTSS on the car in this video. Step height, clutch
dowell pins, bolt part numbers, alignment and various clutch parts are
described in this video. It's part of an all-inclusive drivetrain tech
piece I'm working on that's broken up into sections to maintain focus on
the individual processes involved.
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.
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.
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 107 - 4G63 HLA Lifter Tech
I have all 3 revisions of the DSM lifters in this video. This will help
you identify which ones are in your cylinder head, as well as illustrate
the cleaning process, and each lifters' advantages and disadvantages.
WHEN you finally have to perform maintenance on these lifters, they're a
bigger pain than a solid lift valvetrain is (ONCE). BUT if you follow the
service schedule on a solid lift valvetrain, HLA's are a smaller pain
You'll never need feeler gauges to adjust these hydraulic lifters, and
you'll never need to know their gap. You can't adjust them. You'll just
know whether or not they're good by the amount of noise they make. 3
things can cause trouble with them. Clogged lifters, insufficient oil
pressure, or insufficient oil volume.
So before you sail your oil pump down the river, you can follow the steps
in this video to rule out the first variable. You can actually remove and
re-install them without taking the timing belt or camshafts out, but that
will be another video. Chances are you already know this. The second and
third potential issues COULD be your oil pump, but for your oil light isn't
on and if there's ever been machine work in its past history to either the
head or the block, I explain in "Cylinder Head 103 - Deck Tech" what a
frequently-overlooked part of the cylinder head is that could be a
contributor to the issue. That link is in the video.
I MENTIONED ANOTHER COOL VIDEO: it was here...
Thank that author as well. He did a great job! I don't know the guy and
claim no credit to his work, I'm just giving him a shout-out.
Cylinder Head 104 - Remove Valves & Springs
Just one of many ways to remove valves from a cylinder head. I haven't
seen a valve compressor like this one on YouTube yet. I know it's nobody
makes them like this, because this one is a custom hack job specifically
for 4g63 heads... but it's extremely effective and easy to use.
Since I don't own a valve grinder, valve spring pressure testers (for
installed height measurement), or valve seat grinding stones... there are
several services I'm unable to perform myself. But since I can get the
head disassembled to this state, it would be easier and cheaper for me to
have them serviced by someone who does.
Valve grinding machine time is cheaper if they don't have to tear down the
head. You can lap them in yourself, but if the seat's in really bad shape,
it will require attention to allow any of those efforts to be worthwhile.
Valve seat grinding if necessary needs to be done with the proper tools,
and if the seats must be replaced, then it can get expensive. Usually
$20-ish a hole. Sometimes an oversized bore can be cut into a factory
seat. I'm ordering a set of valves to see if that's possible.