Bearing wear pictures advice/opinions

[tscompusa]

The Vehicle & History:

The vehicle is an Evo 8 with a 4g64 cast iron block (2.4L)
The vehicle runs nothing but E85 and was running on wastegate pressure only, which is roughly 31-32psi and produces 750WHP at this boost level.
There is approx 300 miles of hard abuse on the engine at the time of tear down with Brad penn SAE 30 weight oil only.
I was just about to switch to a 20w50 and turn the boost up and go to the drag strip, but first I wanted to swap to a baffled oil pan

Reason for teardown & post:

The reason for tear down was because upon swapping oil pans from the oem, to a better baffled design, I checked rod side clearance, and it was on the tight side, so I opted to pull the engine and loosen it, which i have now done. But couldn't help myself, so dug into the entire engine down to the main bearings to get some measurements. Moving forward.

Two Pics during assembly to show you what the bearings and engine looks like before being ran:

These are ACL Race Tri-metal bearings, so they have a burned / brown look by default. Just throwing that out there so others know that maybe are not familiar with this type of bearing.





After engine has been boosted / ran for 300 miles roughly with Brad Penn SAE 30 break in oil only:

Below are pictures of the bearings after about 300 miles of abuse at roughly 750whp. Let me know what you guys think on the main bearings.

The rod bearings to me look really good. hardly any wear minus one that got some dirt scratches.







Main Bearings:






Main Bearing wear before & after:

While this vehicle has a crank main journal diameter of 2.244" using the rule of .001" of every inch would give you roughly a target goal of .0022" on the mains.

What I measured on a fresh set of main bearings vertical were .0016" to .0019"

What I measured on the 300 mile old mains they were .0019" to .0021" so clearly it wore itself to the clearance it wanted. (obviously not what we want to happen i don't think)

Final Question and clearance observation:

If I have a range from .0016" to .0019" on a fresh set of mains, would it be beneficial to just throw in a half set of extra oil clearance bearings (.0005" on a half shell)
to get my mains within .0021" to .0024" ?

The rod bearings were in between around .0026-.0028"

Keeping in mind this is a street car as well. Usually when its driven though, its driven very hard.

Thanks in advance. I tried to organize this post so its easy to understand.

[Kalastin]

Looking around here, the notes I have for that engine is the stock clearance for the main and rods bearings are around .0021-.0022. For the amount of horsepower, your engine is making I would like it to be closer to .0025. I would also say that the rod bearing clearance looks a little large to me, but those rod bearings look in great shape except the one that got some trash in it.

Looking at the last picture, it looks like the 2 front bearings were coming into contact with the crankshaft journal because the rear of the first bearing and the front of the second bearing looks polished to me. Looks like a Honda I did one time trying to run a .0011 main oil clearance, polished every main bearing in there,

Mark

[tscompusa]

Thankfully the journals on the crank looks untouched! Maybe its a good thing I tore it down when I did. The 4g64 block has tighter mains then the 4g63. The 4g63 does go around .0021" but the 4g64 goes .0016" consistently from my experience with standard size acl bearings.

Here's a picture of the bearings up close. These bearings used to look the same as each other. The shiny ones of course are the lowers.

Ya the rod bearings looked untouched and perfect, even with SAE 30 oil. For now on i wont boost the car with break in oil. Its really only made for ring seating.

[KnightEngines]

Crank is flexing between journals.

Either that or the crank journals are hourglass shape!

At 750rwhp you have approx 210hp per cylinder belting the crap out of that crank on each firing stroke, it's flexing the crank & pushing it into the edges of the bearings.

The design of the crank may be at fault, the cutaways through the middle shouldn't be there, they do SFA to reduce rotational inertia but they do weaken the crank through there & increase flex.
That crank will likely break at the corner of one of those cutaways, if it's flexing enough to mark up the bearings like that it's gonna fatigue fast.

IMHO get a heavier crank without those cutouts.

Clearance on this sort of jigger should be around .023-.026" on the mains, .018-.022" on the rods.

[Sparksalot]

Crank flexing is on the money. The stock crank was designed to operate under far smaller loads, you're beating on it hard and it flexes and twists more than most folks can appreciate. If you saw a finite element analysis of one loaded as yours is you'd be shocked.

It's standard engine building practice to mix bearing halves from .001 over sets with nominal size sets to hit desired bearing clearances. To crutch it open the main clearance. A better crank would be a big improvement.

[Cubic_Cleveland]

Crank is flexing between journals.

Either that or the crank journals are hourglass shape!

At 750rwhp you have approx 210hp per cylinder belting the crap out of that crank on each firing stroke, it's flexing the crank & pushing it into the edges of the bearings.

The design of the crank may be at fault, the cutaways through the middle shouldn't be there, they do SFA to reduce rotational inertia but they do weaken the crank through there & increase flex.
That crank will likely break at the corner of one of those cutaways, if it's flexing enough to mark up the bearings like that it's gonna fatigue fast.

IMHO get a heavier crank without those cutouts.

Clearance on this sort of jigger should be around .023-.026" on the mains, .018-.022" on the rods.

Ding ding ding!!! I'd re-measure your housing bores, bearings, and crank journals for taper/barrel/hourglass shapes and if all is good it's a crank design/balance issue.

[tscompusa]

Damn I never thought of that. The crank is the super light version of the standard Billet. The standard one is 33lb roughly, this one is 28-29.

So If i throw on the standard Billet for my power level do you think ill be ok? the standard one does not have the cutaways in it like the super light one does.

I will order a new crank and give this one to someone that wont be doing what I'm doing. I plan on making atleast 850whp with this car before the year ends.

Will I be ok with the standard Billet? its 4lb+ heavier without the cut outs.

I checked this block before it was round and normal when bolted down without any bearings in it.

[KnightEngines]

That extra weight is just going to be in the middle, it will make virtually no difference to rotational inertia but it will stiffen up the crank quite a lot & should fix your issue.

[tscompusa]

That extra weight is just going to be in the middle, it will make virtually no difference to rotational inertia but it will stiffen up the crank quite a lot & should fix your issue.

Good enough for me! I had a friend look at these cranks before. I had the standard beside the super light and that's the first thing he said. Wow look at all the material they removed on the super light one. That has to weaken it.

I never thought anything of it.

[Cubic_Cleveland]

Damn I never thought of that. The crank is the super light version of the standard Billet. The standard one is 33lb roughly, this one is 28-29.

So If i throw on the standard Billet for my power level do you think ill be ok? the standard one does not have the cutaways in it like the super light one does.

I will order a new crank and give this one to someone that wont be doing what I'm doing. I plan on making atleast 850whp with this car before the year ends.

Will I be ok with the standard Billet? its 4lb+ heavier without the cut outs.

I checked this block before it was round and normal when bolted down without any bearings in it.

Just because the crank is "billet" (undercut or not), doesn't mean it's the best for your application, or even a good crank. Who makes it?

Also, what fasteners are you using for the main girdle? And how much taper did the bearings have in them when new? Now?

[tscompusa]

Just because the crank is "billet" (undercut or not), doesn't mean it's the best for your application, or even a good crank. Who makes it?

Also, what fasteners are you using for the main girdle? And how much taper did the bearings have in them when new? Now?

Manley turbo tuff crank & rods. new fresh bearings set some of the mains to .0016" vs the old ones were all opened up around .0019-.0021"

I will check the bores for out of roundness. But I recall them being around .0002" last time. Haven't checked after yet.

ARP mainstuds torqued to 60tq with moly lube.

Alittle info on the entire shortblock just for reference since i should of gave it from the beginning:

Its a 2.4L 4g64 bored .020 (87mm bores) with a half fill so i can still use the stock waterpump.
ACL Race main bearings and rods & thrust. all standard size (im gonna put extra oil clearance halves in the upper on the mains to get .0005" more open as long as bore checks out straight when I check it again with no bearings).
Manley turbo tuff i-beam rods
Manley turbo tuff billet crank (BSLW version)
ARP Main studs
Wiseco HD 1400 9.8:1 pistons

[Dan Timberlake]

Might be fun to have the crank wet mag fluorescent particle tested.
If it passes it should be worth more to the person buyin it ( although I'd do over I was buying it).
If it fails, especially with advanced "indications", I'd get a recurring chill every time I thought about it.

[Strange Magic]

While this vehicle has a crank main journal diameter of 2.244" using the rule of .001" of every inch would give you roughly a target goal of .0022" on the mains.

What I measured on a fresh set of main bearings vertical were .0016" to .0019"

What I measured on the 300 mile old mains they were .0019" to .0021" so clearly it wore itself to the clearance it wanted. (obviously not what we want to happen i don't think)

Loosen up the clearances and the engine will look beautiful.

I wouldn't suggest using anything with a viscosity over 5-30 for this application.

.0030-.0033 on the mains and .0025 to .0031 on the rods. The engine will look beautiful once you get the clearances up there.

Personally I would grind .002 off the mains, than lightly wet sand the current main bearings and send them out to Calico for coating. Your net results will be .0029-.0032 on the mains. You can take it apart once more at the same mileage and I guarantee you that it will look brand new, as in never run. I am a big big believer in main coatings. It does make a difference.

Use a race oil with high zinc and phos content. (Synergyn, Gibbs, Red Line, Shaffer)

using the rule of .001" of every inch would give you roughly a target goal of .0022" on the mains.

This above quote is bullshyt!!!!!!!!!!!!!!!!!! Clearances are strictly based upon the quality of the parts and hp levels.

P.S. Expect your oil temps to drop and your power and mechanical reliability to increase.

P.S.S. Your going to need to re-nitride. If it's induction hardened, account for growth.

[Cubic_Cleveland]

Hopefully Jon Schmidt will catch this thread soon and can give his opinion on that crank design. Personally I don't really like how thin those counterweights are. I remember fixing someone else's mistakes when a customer had a crank with counterweights "optimised" like yours. The bearings always looked terrible, and he couldn't see from the vibrations even though the crank was balanced within .5g when spun up. Put a stiffer crank with heavier counterweights (that had an aerodynamic profile) in, and no more problems.

I don't think opening up clearances to .0033" on the mains is the correct approach. Whilst it might fix the symptoms, the problem still exists. Knight Engines is on the money ~.0025" mains, ~.002" rods is what I'd shoot for.

[vwchuck]

Those clearances are way too tight for the oil you are using. 20w50 needs .0025 and up on everything. More RPM and PWR the bigger the clearance. Most 4 cylinder cranks at the power levels you are at are on borrowed time. I would consider the crank a consumable item. Mag check it and you will see all the crack forming in the radius' of all the journals.