I'll read up in that thread and get the book too..i just got the oil pan off last night so I'm going to finish everything today since its 54 degrees here in WI today

 

You do know that some great shops, like Buschur, recommend NOT grinding the OEM crank. They say if you do, it will eat bearings like thats its job.

All they recommend is polishing.

 

From EVOM posted to DSM Tuners.. now posted back on EVOM

I pulled this from a post from a friend on EvoM this was done on an Evo 8 crank, it was a very well known shop in Germany that did this test. I provided a crank for this test.

We did grind a crank down all the way to determine the deep of the hardening.
The hardening is not nitrite, its inductive hardening ( thats the reason why you can polish the crank.
It was an used Evo8 crank with an rod bearing failure on cyl.1, which was trash anyway due to the failure
We started to grind the number 2 Rod surface.
ALL dimensions in metric (mm) here. Hardness is not an absolute value in our case, its relative measurement!!

Initial : 47.993mm Fillet depth: 0.49mm Hardness: 88
1st grind : 47.893mm Fillet depth: 0.39mm Hardness: 88
2st grind : 47.743mm Fillet depth: 0.24mm Hardness: 88
3st grind : 47.493mm Fillet depth: none Hardness: 86
4st grind : 47.243mm Fillet depth: none Hardness: 84
5st grind : 46.993mm Fillet depth: none Hardness: 68 hardness drops fast

So , in conclusion, you can grind the Crank Rod pin ( only rod testet ) down.
so, 0.25 mm is possible when the fillets should be there and 0.50 mm if fillet doesnt matter or can be refreshed.
Any more does not make it because fillets gone and also hardening drops ( extreme loss after the -0.75 grind )
Also, the grinding should be done in an really smooth way, so it should not be done like an V8 crank. There should be removed only a small amount of material, with cool down times in between. The hardening can change extreme if to much heat is transfered into the crank. ( tried that at Rod position 3, more material in one grind, hardening changes 5 more point than rod 2 )

But, there is an other problem you will run into.
All Bearing manufacturers doesn't make the right bearings for the turbo application.
The max grind to get Turbo bearings is -0.25mm. smaller to get bearings from them.The bigger OS will be only for the N/A 4g63 / 4G64.
This was approved from King bearings, the materials and coats used will be different than and they do not advise to use in high HP applications.
Same Information from Clevite, ACL and Glyco.
Also, Mitsubishi has different bearings ( but same dimensions ) for the 4g63T and 4g63 n/a Engines.

It may be possible that someone has get Bearings as an custom order, but not "off the shelf".

For my self: For an almost stock Evo ( stock turbo ) i would use an g rinded crank (-0.25) when an new one is not in the price range..
In any high HP application ( 500++) i would never used an grind crank.
Get an new or good used one. Better safe then sorry.

here in Germany, its easier and cheaper to use an new crank all time, because the grinding is expensive. Grinding all 4 rod sections is about 500$.
In the states, i assume, it will be much cheaper because you have more Engine shops then here in Europe.

 

^^ Umm okay. What shop said that? Also, that test doesn't really say anything, because they didn't reinstall the crank to see if it would eat bearings.

Most all the big US shops dont recommend doing any type of grinding/cutting to the OEM crank. Only polishing or get another OEM or an aftermarket one.

 

Well, personally, I have installed three .010/.010 cranks in 4g63 engines, 1 6 bolt, and 2 7 bolts.

All running 350+ HP one over 400 the last I heard. No issues with the cranks, But I do pay extra to have then gound at a slower rate, so not to weaken the hardning of the crank.

There is no reason for a crank to "eat bearings if the harding of the crank has not been compromised.

Also the same belt used to polish a crank, is the same belt used to polish a crank after it is ground.

One way a crank might eat bearings is if the crank was ground or polished in the wrong direction.
The mico fractures of the crank will face the wrong way and want to dig into the bearing.

Another reason rod bearings get chewed is an improperly cleaned crank.
The rod throws are of a crossed drilled design,with an intersecting oil galley to the main. Thats the reason for the ***** pressed into the side of the rod throws.
There is a dead space from the edge of the rod bearing oil galley,to the outer edge of the rod throw. appox .225 Dia X .750 long,

Now over the years, since oil does not flow, it get packed with crud, now on a rebuild, The DIYer will run break clean in there to try to clean it, and it will to a point.
A machine shop will put it in a spray cabinet,or hot tank.

All 3 of these methods will get some but not all of it. But all 3 methods will start to break down the crud.

Now intall the crank, prime the engine, start the engine and go drive, now the soften crud goes straight into the rod bearing.

Now if the crank was ground, having a ground crank will be the blame.

Also keep in mind when the crank was ground, metal from the crank along with grit from the crank grinding stone, and abrasive from the crank polishing belt all went through the main oil galley, and the cross drilled oil galley of the rod.

Now what is standard procedure with me, is to remove the press fit oil galley ***** in the crank, and remove the crud build up.

Is this crud build up just common to the 4G63 crank? No it is not, Nissian RB26DETT, Mazda 1.8BP are a couple others I found with this issue.

I have noticed some of the big aftermarket crank grinders that supply crank kits to auto parts stores have been removing them also.

 

I doubt Buschur is grinding cranks wrong or installing anything incorrectly. And when MR. 4G63 says that a crank that has been ground will eat bearing, Im gonna believe/listen to him over you, sorry.

 

Last time I heard, he did not grind cranks, or bore blocks......

Ill look into it some more, and see if I can find a logical reason why the 4g eats bearings on a ground crank.

 

Yes, he does not grind cranks and recommends against it. But why does he recommend against it... because he did it before and it eats bearing like crazy, according to him.

 

I may give him more credit if he did his machine work in house.
But that is all done at another machine shop, then he does the assembly.

So he really has no idea how the crank that failed was ground.

I have spoke with another well known 4g63 Engine builder, and they do build engines in the 500+ HP range. They have no issue using a properly cleaned and ground crank.

Can you tell me another engine that "eats bearings" when the crank is ground?


The crud I remove from behind the oil galley ball in the rod throw of a 4g63 Crank.

 

Ok i am almost complete with the tear down...i have also been doing a lot of research..i don't want the 2.0l anymore so im debating on going 2.3/2.4l..i have read these will last longer and are better for dd as the 2.0l are great for drag and high rpms..so the great debate of 2.3 vs 2.4l begins..while the 2.3l is the more common choice people have said..why go 2.3 when you can go 2.4? People have also debated that the 2.4 will last longer..any truth?

As for the block I'll be going .020"

And the crank..you guys are confusing haha..no harm in that..if i decide not to have it grinded and just knife edged and micro polish it will i still benefit?

 

I don't think 2.0, 2.1, 2.2, 2.3, nor 2.4 have different life expectancies. It really all depends on the tune, how well it was built, how much you beat on it on a day-to-day basis, etc. Too many factors to put in on how long the block will live.

Between a 2.3 and 2.4, if the stock block in just fine, go 2.3. You might save a couple bucks. But if the block is blown and you're on somewhat of a budget, 2.4 since those motors can be found for much cheaper than another Evo motor. Or if you don't feel like tearing your motor out of the car and having the car sit for a long time, you can buy the 4G64 motor, build it slowly, then swap it in when it's done. Difference between 2.3 and 2.4 isn't big. The turbo will spool a tad faster but that's it. Haven't really seen a 2.4 make a much bigger power than a 2.3. This is just my opinion on the 2.3 vs 2.4 debate and others might have a different view on it.

As for the crank, I wouldn't even touch it except get the balance checked and get it polished. Most likely, the stock cranks are already balanced, like they should be from factory. Only reason why I recommend balance is because who knows what happened to a used crank. Might look fine but once you rotate it, you can see if it's warped or not.

 

If you have 5k to build the lower end of a good spare block with oil squirters and crank......
https://secure.buschurracing.com/cat...d2d7e6282b2de0
All of those are already assembled. Or if you want the experience of building it yourself do what you are doing.

or MAP or English Racing. Theres plenty of engine builders in the US that have delt with the 4g63/64 motors.


To me if you are going to spend 5k let someone that has been doing short blocks for years assemble it. Years of experience are worth it. Just my .02