ACL rod bearings?

[Helmsman]

Originally Posted by Green-Eggs

Too much clearance isn't good either.



Based on an email he had with ACL, the guy seems convinced this is normal wear. It's hard for me to look at that and see "normal wear."

https://www.facebook.com/groups/2523...4324066222146/

https://www.facebook.com/groups/2523...9145049073381/

Confusing post all together while one thing seem clear, the crank shown can't possibly be optimal for any bearing, BE included.

[Green-Eggs]

Originally Posted by Helmsman

Confusing post all together while one thing seem clear, the crank shown can't possibly be optimal for any bearing, BE included.

Agreed. I would never use that crank without repair, regardless of bearings. The OP said those bad shells came from a different journal though.

[E92_tim]

I am new to the E92 forum and was looking for a clear answer as to the rod bearings replacement. I am considering the E9x M3 - S65 ACL Rod Bearings and ARP Connecting Rod Bolts. Is this the best option? I apologize if this has already been answered. Thank you in advance!

[Green-Eggs]

Originally Posted by E92_tim

I am new to the E92 forum and was looking for a clear answer as to the rod bearings replacement. I am considering the E9x M3 - S65 ACL Rod Bearings and ARP Connecting Rod Bolts. Is this the best option? I apologize if this has already been answered. Thank you in advance!

This is a thread specific to ACL. You will get different recommendations from different vendors. BE Bearings are considered the gold standard. Just remember, too much clearance is just as bad as too little clearance. Do your research.

https://www.m3post.com/forums/showthread.php?t=892838

[jvictormp]

Originally Posted by Green-Eggs

Too much clearance isn't good either.



Based on an email he had with ACL, the guy seems convinced this is normal wear. It's hard for me to look at that and see "normal wear."

https://www.facebook.com/groups/2523...4324066222146/

https://www.facebook.com/groups/2523...9145049073381/

On the first link, when you follow until you find the pictures in reference, you also find that the guy was using old OEM bolts (which means reusing, which is prohibited)

[Green-Eggs]

Originally Posted by jvictormp

On the first link, when you follow until you find the pictures in reference, you also find that the guy was using old OEM bolts (which means reusing, which is prohibited)

Huh? I wouldn't be so quick to draw that conclusion. About 50% of all rod bearing changes today are using new, not reused OEM bolts. I've never heard of a single case where people are reusing OEM bolts during a rod bearing change.

[jvictormp]

Originally Posted by Green-Eggs

Huh? I wouldn't be so quick to draw that conclusion. About 50% of all rod bearing changes today are using new, not reused OEM bolts. I've never heard of a single case where people are reusing OEM bolts during a rod bearing change.

That seems odd, I agree. But that's what is written.

[jvictormp]

@green-eggs

[Green-Eggs]

Originally Posted by jvictormp

@green-eggs

He admitted that he did not change these rod bearings. He could not possibly know if the original rod bolts were reused or not. I don't think English is his native language, and that is a more logical explanation of the wording.

[jvictormp]

ACL h-std after 3.000km (just wanted to see if they're okay before the first trackday with this new engine).
They are clearly worse than the be bearings I had with previous engine when it blowed (hydrolock) with 8.000km on the bearings.
I know this bearing is not gonna last forever like be would.
Pretend to go back to be when I have the budget.

The first pictures are ACL bearing.

The black bearing (last picture only) is the BE.

[Helmsman]

Originally Posted by jvictormp

ACL h-std after 3.000km (just wanted to see if they're okay before the first trackday with this new engine).
They are clearly worse than the be bearings I had with previous engine when it blowed (hydrolock) with 8.000km on the bearings.
I know this bearing is not gonna last forever like be would.
Pretend to go back to be when I have the budget.

The first pictures are ACL bearing.

The black bearing (last picture only) is the BE.

Interesting. Yeah, they seem to have been touched. I assume the BE shells not are from the same engine? (or are they from previous locked engine maybe? I can't remember the details).

[jvictormp]

Originally Posted by Helmsman

Interesting. Yeah, they seem to have been touched. I assume the BE shells not are from the same engine? (or are they from previous locked engine maybe? I can't remember the details).

Be shells were in the blown engine (due to hydrolock).

ACL shells were (and are) in the new engine.

[tdott]

Originally Posted by jvictormp

Be shells were in the blown engine (due to hydrolock).

ACL shells were (and are) in the new engine.

Also worth noting that the ACL are the H versions so pretty much stock clearance target, I wonder how a mixed set would have done.

I think comparing any stock clearance bearing to BE will show wear.

In a perfect world if someone could run a measured mixed set of ACL bearings in the same motor for X amount of miles, and BE bearings in the same motor for X amount of miles. I'm not sure there would be much of a difference. But the BE is a better bearing with better Quality control, best chance of hitting target clearance and it has a low friction coating.

[Green-Eggs]

Originally Posted by tdott

Also worth noting that the ACL are the H versions so pretty much stock clearance target, I wonder how a mixed set would have done.

I think comparing any stock clearance bearing to BE will show wear.

In a perfect world if someone could run a measured mixed set of ACL bearings in the same motor for X amount of miles, and BE bearings in the same motor for X amount of mines. I'm not sure there would be much of a difference. But the BE is a better bearing with better Quality control, best chance of hitting target clearance and it has a low friction coating.

There's also a new BE Bearing V2 shell with silver oxide coating instead of Calico PTFE. Not planning to use this thread for that discussion. Look for an announcement in another thread soon.

[Helmsman]

Originally Posted by jvictormp

Be shells were in the blown engine (due to hydrolock).

ACL shells were (and are) in the new engine.

Got it, thanks. Went with ACL HX myself so hope they've managed better.

[Redd]

Originally Posted by jvictormp

ACL h-std after 3.000km (just wanted to see if they're okay before the first trackday with this new engine).
They are clearly worse than the be bearings I had with previous engine when it blowed (hydrolock) with 8.000km on the bearings.
I know this bearing is not gonna last forever like be would.
Pretend to go back to be when I have the budget.

The first pictures are ACL bearing.

The black bearing (last picture only) is the BE.

Thanks for sharing that. Probably the single most informative post on BE vs ACL. I know which one I will use for my next RB change.

[nycplumber]

It's an oem sized bearing vs an oversized bearing. Obviously the oem sized one will show more wear. Thats common sense and the entire reason RB are an issue. How you can look at that and come to a conclusion of just using BE is strange.

[jvictormp]

Originally Posted by nycplumber

It's an oem sized bearing vs an oversized bearing. Obviously the oem sized one will show more wear. Thats common sense and the entire reason RB are an issue. How you can look at that and come to a conclusion of just using BE is strange.

If it's strange, I can clarify.

I don't undestand ACL offers a same spec product as BE. It has either less clearance than BE (H), either more clearance than BE (HX). The later may lead to insufficient oil pressure at high speeds, I can't gamble about that, because if it does, I fear that could even mess up with the mains. The former does make contact, but it's enough for some miles, as we know well, because the first genuine bmw shells I extrated were "normally" worn with 40.000km. So, if ACL H-STD keeps the clearance, it will be enough for more 40.000km.

That's why the only comparison I would make would be ACL H-STD vs BE.

Interesting to note that BE-ARP bolts are on their third torque now, and doing good.

[nycplumber]

Bla bla bla it "may". You have no evidence of ACL wearing out slower or faster than BE under same conditions. Again you're comparing oem clearance to a revised clearance. The only correct comparison is revised vs revised and that hasn't been done. Until then it's best to not make assumptions because anyone reading it will take it as fact and it's far from that.


This is where comparisons should be made
https://store.langracing.com/product...bmw-e9x-m3-s65

[jvictormp]

I didn't say that, it's you that are concluding something different from wrote.

Fact is.

I have ACL h-std. It has made contact, and it shows a little wear.

I will not use ACL hx-std, reasons are above.

I will use be the next opportunity, or, if needed, ACL h-std again.

[nycplumber]

That's cool but no one asked for your opinion. You replied to a comment for someone else and brought nothing of value to the discussion. Yes a bearing with oem clearance will have excessive wear. Welcome to Rod bearings 101

[jvictormp]

Wow. That's rough.

I'm glad to help whoever would like to know what I posted, although it's not appreciated by you.