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 doing here.
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 6-bolt block.
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.
4g63 Block Oil Gallery Mod
This modification is intended to improve your 4g series engine's oil
delivery. People frequently discover large chunks of flash in their
engine's main oil gallery. It's because the galleries are part of the
cast, they're not machined into the block. There is also a very rough
sharp edge where the main oil gallery is bored into the block, and oil must
make a slightly greater-than 90° turn in order to begin its course to the
parts it lubricates. Both of these conditions cause turbulence in the oil
flow. My goal in this video is to eliminate as much of that as I can.
This is a cheap and easy modification if you have the tools, and the
patience. Any engine with cast-in oil galleries could probably benefit
from this. Be careful not to cut into the high pressure oil gallery or
else you will circulate un-filtered oil to the #1 main, oil pump, and rear
balance shaft. You will also deprive the rest of the engine the oil
pressure it needs to operate. So in short, punch a hole in that and it's
trash. I did this my way, everyone may choose to do this a different way.
I just wanted to make this video to raise awareness.
Also, there's a great thread on DSMtuners about this. Pictures and
everything. Written by a machinist and friend of the DSM community. Go
give him some reps because he's posted a lot of great info about the DSM
oil system over the years.
Block Preparation Part 1
Preparation for powder coating and Glyptal application. Audio track is an
original performance by Rojo Del Chocolate.
My block is being powder coated rather than painted. It's just something I
do. The GSX had it on the last block so it's getting it again.
Since the tools are so similar and the mess is the same, I'm going ahead
and preparing it for the Glyptal application as well. These 2 coatings
will require being baked separately. The powder coating is baked on at a
hotter temperature than the Glyptal, so it's going first.
The surface preparation instructions for Glyptal is as follows:
Surface to be painted should be dry and free from dirt, wax, grease, rust
and oil. Remove all grease and oil by washing surface with mineral
spirits. Wipe or scrape off all loose dirt, rust or scale.
The last sentence is what's covered in this video. The 2nd sentence
happens next (although it's already degreased), and I'll get it back from
powder coat with it in the state described in sentence #1 completed. If
following these instructions to the letter of the law.
Second and third opinions in... the main journal is fine.
You'll notice that I didn't coat the main caps, or "suitcase handles". I'm
not going to. You bang around on these installing and removing them, and I
don't want to risk chipping them once they're coated. They're below the
windage area, and there will also be an un-coated main bearing girdle down
This video covered 25 hours of actual work. Yes, I kept changing into the
same filthy clothes every shoot because I wanted it to look consistent.
You have to take your time doing this kind of work, and be VERY VERY
CAREFUL! If for some reason you're crazy enough to attempt what I do in
this video, you do so at your own risk. This is an elective treatment that
I've never done, but I am by no means the first person to do it. I'm
learning about it just like the rest of you.
Jafro's GSX Build Parts - 1gina2g
Some advice and expectations about the parts acquisition process. Cars
only get built in a week on TV. And still then you have to take their word
for it. The ones that actually do it have a 20 man full-time crew, and
therefore; they have no excuse for not having it done yet.
We don't have that. Stuff takes time. I'm not building a car to sell it.
There's a whole lot of parts in this video. Whole lot of parts. Rather
than spend a ton of space babbling incessantly, this is what you came here
for. Part numbers. Meat. This isn't an all-inclusive list of parts for a
rebuild. It's what YouTube let me fit. I hope you find what you needed.
If not, hang tight. Help is on the way.
Shoutout to Sirnixalot in the Cayman Islands for this thread about
valvetrain part weights:
MF140202 - Bolt, Engine RR Plate Flange M6 x 10 (2qty)
MD012109 - Bolt, Engine RR Plate Washer Assembled 6 x 16 (2qty)
MF140202 - Bolt, Timing Belt Cover Flange M6 x 10 (4qty)
MD167134 - Bolt, Engine Oil Pan (2qty) Flange M6 x 8
MD097012 - Bolt, Engine Oil Pan (17qty) Flange M6x10
MD131417 - Bolt, Timing Belt Cover Flange M6x16
MD040557 - Bolt, Flywheel (6qty) M12x22.5
MS401451 - Stud, M10 x 28 Cylinder Block
MD065945 - Plug, Cylinder Block Screw (balance shaft)
MS240211 - Bolt, Crankshaft Pulley Washer Assembled M8x25 (4qty)
MD129350 - Bolt, Timing Belt Tensioner (2qty) M8x51
MD129354 - Bolt, Timing Belt Train M10x33 Happy Face Bolt
MF140062 - Bolt, Engine Front Case M10x30
MF140225 - Bolt, Engine Front Case M8x20 (4qty)
MF140227 - Bolt, Engine Front Case M8x25
MF140233 - Bolt, Engine Front Case M8x40
MF241266 - Bolt, Oil Filter Washer Assembled M8x65
MF241261 - Bolt, Oil Filter Washer Assembled M8x40 (2qty)
MF241268 - Bolt, Oil Filter Washer Assembled M8x75
MF241264 - Bolt, Washer Assembled M8x55
MF140021 - Bolt, Cooling Water Line Flange M8x12
MF241256 - Bolt, M/T Clutch Slave Cylinder Washer Assembled M8x28
MD718549 - Bolt, Transfer Case Washer Assembled M12x130 (3qty)
MF241319 - Bolt, Transfer Case Washer Assembled M12x70 (4qty)
MD706012 - Bolt, T/M Connecting Flange M8x60
MD108474 - Bolt, Starter Flange M10x65 (2qty)
MF140266 - Bolt, T/M Connecting Flange M10x40 (2qty)
MD740892 - Bolt, T/M Connecting Flange M10x43.5
MF140471 - Bolt, T/M Connecting Flange M10x65
MD706012 - Bolt, T/M Connecting Flange M8x60
MF140021 - Bolt, T/M Connecting Flange M8x12
6-bolt Rear Main Seal Housing:
MF140205 - Bolt, Cylinder Block Flange M6 x 16 (5qty) Rear Oil Seal Case
MD040330 - Case, Crankshaft Rear Oil Seal
MD040332 - Oil Separator Crakshaft rear oil seal
MF472403 - Pin Cylinder Block Dowel 6x14mm (2qty)
MD183243 - Gasket, Rear Oil Seal Case
7-bolt Rear Main Seal Case MD172170*
* oil separator ring only required on 6-bolt cars, same oil seal, different
Throttle Body Gasket:
8903.1-9006.1 MD125822 1g
9006.2-9207.3 MD146399 1g (AC60-653)
9208.1-9405.1 MD194578 1g
9401.1-9907.2 MD180360 all 2g cars (MD1)
Intake Elbow Gasket:
8903.1-9207.3 MD340327 1g
9208.1-9405.1 MD194827 1g
9401.1-9907.2 MD302262 all 2g cars
MD307343 - OE Valve Stem Seals (16qty)
MD087060 - OE Fuel Injector Insulator (4qty)
MD614813 - OE Fuel Injector O-Ring (4qty)
MD181032 - Gasket, Exhaust Manifold
MD188995 - Gasket, 1g Intake Manifold
MD192031 - Gasket, 2g Intake Manifold
MD183808 - Gasket, Standard Composite Head Gasket 89-99
MD069879 - 1g Sensor Coolant Gauge Unit
MD177572 - 2g Sensor Coolant Gauge Unit
MD310606 - 1g/2g alternator belt 985mm
MD186124 - 1g/2g alternator belt 980mm
MD186784 - 1g/2g Valve Cover Gasket
MD186785 - 1g/2g Spark Plug Well Gaskets (4qty)
MN119896 - 1g tensioner arm
MD170402 - 2g tensioner arm
MD997608 - 1g thermostat kit
MD315301 - 2g Thermostat Kit
MD141510 - 1g Knock Sensor
MD300670 - 2g Knock Sensor
MD133273 - 1g/2g Oil Pressure Gauge Sensor
MD091056 - 1g/2g Coolant Temperature Switch
MD095656 - 6 bolt clutch cover plate
MD191171 - 7 bolt clutch cover plate
MD178430 - 1g Power Steering Belt
MD310617 - 2g Power Steering Belt
MD311638 - Oil filter cap gasket
MD343564 - Oil Seal, Crankshaft Rear
MD030764 - O-ring, Cooling Water Pipe 33.4mm
MD375091 - EVO 8 Rocker Arm
6-bolt 4g63 Kiggly Main Girdle Install
Ballos Precision Machine was nice enough to let me into their operations
and film the installation of my 6-bolt Kiggly Main Girdle. They let me do
this as a gift to all of you.
THIS IS NOT THE FINAL INSTALLATION.
Though all the parts were cleaned prior to pickup, they will be extensively
cleaned again, and the fasteners installed finger-tight with red Loctite
exactly 15mm above the surface of the main girdle and torqued in the proper
My main caps were level and straight, the crank bore was straight to begin
with, and had never been line bored following the original assembly at the
Many of you have seen this one before. I apologize if bringing it back
Domestickilla gave me a crankshaft, and it's a nice one that I want to
clean up and use again. You'll be seeing a lot of it and because of this,
this video deserves to be here. I fixed what I broke, and this was my
In this video Ballos Precision Machine demonstrates magnetic dye penetrant
testing, crankshaft polishing and inspecting the balance of a "butchered"
4g63 6-bolt crankshaft.
Major Huge Announcement
This video is a quick update on the projects here on Jafromobile right now,
as well as a tour and history lesson on my latest addition. I'm always
hard at work to bring you all new material based on Mitsubishi production
and partnerships from 1987-1999. Also covered are what's necessary to
resurrect a car that's been sitting for many years. If it's got a 4g63, to
me... it's always worth saving. My channel now has 4 Mitsubishi-powered
projects in the works which should be capable of delivering tons of new
I'd like to welcome all of you from the forums. My history with Mitsubishi
began in 1997, and hasn't taken a day off since. Owning one of these has
been long overdue for me, and you guys have been a wealth of knowledge that
helped me along my travels. An asset to the DSM community, even though
this isn't a DSM.
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
4g63 Timing Belt Parts
I don't care which DOHC 4g63 you've got. This is the video for you. All
the parts and tools necessary to do the job right, right here.
I know some people will ask about aftermarket timing kits. I'm not a fan.
There are some things you can not skimp on. IMO, anyone using aftermarket
parts on an interference engine have put the cart in front of the horse.
Interference engines are engines whose pistons and valves share the same
space at different parts of the strokes. If the timing belt (which is
responsible for preventing them from doing that at the same time) breaks,
or a pulley seizes up, then what follows goes something like this...
"Hi piston, I'm valve", valve said.
"Oh hey there, valve... Who's your friend that I just stepped on there?",
said the piston to the valve.
"Oh, her? That's my wife, and now she's a little bent out of shape now.",
"I brought my whole crew, and they're next door introducing themselves to
the rest of your friends.", piston uttered matter-of-factly.
"So I hear. It sounds like they're done already.", said valve.
"Yep, I'm afraid we are, too. Sorry about your wife there..."
Aside from damage to pistons and valves, it can crack guides, damage rods
and wrist pins, crank bearings, you name it. Worst case is when the valve
face breaks off and chews up the cylinder head. No valve job will ever fix
Use factory parts for your engine timing.
MD326059 - OE 4g63 Timing Belt
MD182295 - OE 4g63 Balance Belt
MD972052 - 1g water pump
MD972050 - 2g water pump
MD129355 - Happy Face Pulley
MD156604 - Timing Idler Pulley
Water pump bolts:
Timing tensioners: prod. date
MD164533 - 8904.3 - 9204.3
MD308586 - 9205.1 - 9405.1
MD308587 - 9401.1 - 9508.2
MD308086 - 9508.3 + 9999.9
Balance belt tensioner pulley:
MD115976 - all 1g
MD192068 - 95-97.5
MD352473 - 97.5-99
CRANKWALKED? 7-bolt teardown 1080HD
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,
'n 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 all depressed cause I seen this before.
I got my books and my wrench and we'll do it once more.
I sprang into action like lightning disassembled
I whistled while I worked and my hands never trembled
If anything you could say that this bling is rare,
and when I saw what broke I 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.
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.
Hyundai Assembly 5 - Fighting The Valve Clearance
In previous videos I showed the 2 factors that really need to be
scrutinized. Valve clearance and how you degree your camshafts. Of course
we got sidetracked with plenty of other tips and tricks but I wanted to
upload this video to illustrate that the process really isn't as easy as
the animations, demonstrations and explanations make it look. The
reasoning is sound, but the work to execute it can be very tedious.
Setting up the valvetrain on this engine was very tedious. I say "was"
because following this video, we can put that whole topic to bed. This is
what it took. Not many people have the patience to deal with this, and I
wanted to showcase here for those who are at the peak of their frustration
with their builds. This kind of stuff can happen to anyone. Let my pain
and suffering help you not feel so all alone.
My apologies for the lack of new groundbreaking technical info. It's not a
complicated task to install ARP head studs, and that was my plot twist.
There are a couple of hurdles you may encounter depending on the production
year of your engine, but they're well illustrated in this video. I'm not
sure if their installation warrants a video all unto itself, but if you
feel it does, speak up because I have 3 more engines to build. I can still
I just wanted to demonstrate that progress is being made on this, and
despite the long breaks between uploads, a LOT is going on behind the
scenes. This was 20 hours of repetitive work and I hope it's at least
mildly entertaining. For me, this was the most boring video I've ever
edited here because I had to re-live the same steps so many times, over and
over again. I could very easily have inserted an hour of it in the wrong
place and nobody would ever have known because it all looks the same. The
text overlays are there only so you can be aware of what's different. A
voiceover would have been pointless because the techniques illustrated are
discussed ad-nauseum in the Cylinder Head 205 and 206 videos. The valve
cover gasket installation process was covered in "Valve Cover Modification
and Polishing", and the discussion about compression ratios is explained in
"Calculate Your Compression Ratio". If you like the job the parts washer
did, check out my DIY parts washer video. ;)
Cylinder Head 205
Cylinder Head 206
Valve Cover Modification and Polishing
Calculate Your Compression Ratio
4G63 Mitsubishi Powered Mustang - WTF?!
Never would have thought we would see a 122ci 4G63 Mitsubishi powered Fox
Body Mustang when we went
to Georgia for the LIGHTS OUT V drag race (DVD Pre Order -
This unique x275 car, built by CDub Racing out of Louisville, KY caught
everyones attention at the race just by the freak noise that it put out
compared to the rest of the field.
Full article on the car -
4g63 Oil Filter Housings
The link to my website is here BUT THE DATA AND PAGES ARE NOW BEING
CREATED. I couldn't leave you without a video any longer. I really will
have a link here very soon that goes straight to the information. To prove
I'm not bullshittin' you... here's the website. http://www.jafromobile.com
It's full of placeholders and copy I did not write. Though I did not write
it, the author knows me very well! There will be highly-detailed
measurements of all the pieces parts available shortly.
I suppose if there was anything else I needed to say here it would be...
these are the filter housings I got my hands on and tested. They happened
to be from each of the models of the mainstream cars with a 4g63 in the
United States with only one exception (EVO III). There may be variations
from year to year, but to be as specific as I possibly can, read on...
The 91-94 housing I demonstrated is specifically from an early 1992
6-bolt/4-bolt turbo AWD car. The one I
call 95-99 is specifically from an October '94 built 1995 model Eclipse
GSX. One of the '90 OFH's was brand new, and the other one on the Colt
came from a 1990 Plymouth Laser FWD.
The Galant housing I have no data on. I was told that's what it was. It
may actually be from a non-turbo
Eclipse? The 1990 factory service manual has an illustration of this oil
cooler-less unit. I've never paid attention to this in the junkyard and I
haven't owned a NA 4g63. Do the 1g non turbo DSMs even have oil coolers? You guys know
better than me.
The non-turbo oil filter housing is the
least restrictive because it has the longest spring installed depth. The
non-oil-cooler blocks are the no-oil-squirter blocks. Get how these are
similar? You put an oil cooler on this thing and your pressure goes up.
Look at the charts.
Put an external air-oil cooler on a 1g? Your pressure goes up. Put the
Evo III housing on a 2g? Pressure goes DOWN. High oil pressure can result
not just from how you built your motor.
Last thing to say... Yes, you could easily INCREASE your spring installed
height by using a THICKER crush washer. That would lower your pre-load,
opening pressure AND piston travel across the port prior to spring bind.
Could you double-stack crush washers? Probably. Will it leak oil? I'm
sure it will eventually. Either bore the cap deeper or machine a 1 piece
part is my recommendation. Would I try it with stacked crush washers?
Most definitely. Look at what you have to do to remove and port it.
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.