Custom ACL Bearings, thoughts?

[saucn]

I know most people (or so I've heard) go with BE Bearings over ACL due to clearance but I'd like to go with ACL for the obvious savings. However I've heard that ACL makes their set oversized which comes out to 0.25" or something like that.

Found this set and saw that they were customized to have 0.0023" to 0.0025" clearance. Would the better clearance be ideal? BE's is something like 0.025", right?

Trying to figure out which ones to go with for my long overdue RB service coming up soon.

[M3SQRD]

Who’s the vendor? Past vendors have been caught selling custom measured ACL bearing sets but weren’t actually measuring them. Non-measured ACL clearance has tolerances that can result in clearances that are too tight. Actual measured custom sets will provide extra clearance. I went with BE bearings and BE ARP rod bolts. The $300 difference in cost isn’t significant in the long run. I wanted a solution that put to bed the rod bearing concerns.

[tsk94]

Assuming you aren't installing these yourself. The small parts price difference between the BE option and ACL is a small percentage in the grand scheme of the whole job.

If it's a reputable vendor selling measured sets of ACL, sure. Otherwise BE is the safest bet imo.

[Helmsman]

Been driving on ACL HX (from fab extended clearance) since 6y/20k miles. All good so far.

[NeverL8]

It’s a $15k used engine replacement, why worry about couple hundred bucks difference? Go with proven and reliable parts

[Brandoch]

Originally Posted by NeverL8

It’s a $15k used engine replacement, why worry about couple hundred bucks difference? Go with proven and reliable parts

What makes BE more reliable then ACL?

Does ACL have a bad reputation?

I have no idea why everyone in this forum seems like engineers and engine builders.

Just because you or someone else choose a certain company/product does not mean that every other one is going to blow up your engine.

[Green-Eggs]

Originally Posted by Brandoch

What makes BE more reliable then ACL?

Does ACL have a bad reputation?

I have no idea why everyone in this forum seems like engineers and engine builders.

Just because you or someone else choose a certain company/product does not mean that every other one is going to blow up your engine.

Better materials, better backing, better babbitt, silver oxide over lead indium
Higher load capacity
Greater seizure resistance
100% quality control
Every shell is hand measured, sorted, binned into matching sets to nominal BE clearance specs
Engine replacement warranty

[nycplumber]

A lot of people on here drank the BE kool-aid. I have ACL bearings by Lang. Put 10s of thousands of hard supercharged miles on them and obviously everything is great. The fact is ACL is used at the highest level of racing including Nascar, IHRA and NHRA. BE has not and never will accomplish what ACL has. Yes they came out with a paper that a bunch of nerds salivate over but would you rather buy from a company that is consistently on podiums or one who's website looks like was created by a middleschooler.

[M3SQRD]

BE bearings are manufactured by Clevite, owned by Mahle, who have an even more impressive combined resume than ACL.

[nycplumber]

Originally Posted by M3SQRD

BE bearings are manufactured by Clevite, owned by Mahle, who have an even more impressive combined resume than ACL.

Which is why they have to hand measure each one because it's not their machinery doing the manufacturing process. Vertical integration will always be the best way to build a product and the further you are from that the more mistakes will be made. Anyone could simply search 'clevite bearings failure' and you'll have endless choices on Google to pick from

[S85 builder]

I've used both and have never had issues in the S85s I've done with mine or the customer's, who loves to do Blackstone reports (which I don't really think mean much for rod bearing monitoring). This dates back to 2019. Aside from acceptable clearance, cleanliness at install is the most important issue. The issue for BE in the past was lack of availability bearings since they are made in batches at Cleveite.

Also for those who drive in the winter and live up north, it really makes little sense to be using 10W60 in the winter.

[saucn]

Wasn't getting notifications on the replies for some reason. Euro Power Motorsports is the vendor I'm looking at.

They've got the extra clearance and the custom clearance variants but since the issue with OEM bearings is the clearance, I'm leaning more towards the custom clearance ones.

[saucn]

Originally Posted by NeverL8

It’s a $15k used engine replacement, why worry about couple hundred bucks difference? Go with proven and reliable parts

What makes ACL not proven and reliable? In your opinion.

[charliev68]

Is it everyone’s opinion that BE RBs or ACL is the end all solution? Would you trust them for the life of the engine?

[S85 builder]

Either one is better than stock or coated ones IMO. BE may have better dimensional accuracy, that's what you're paying for, but what really matters is the actual clearance of all the components on YOUR engine. So my advice as an experienced builder and engine machinist is to fully blueprint your crank while you have it out. I know some people don't like what I have to say and level personal insults at me, but always measure when it's possible.

Then the bearings can be selected to fit, this might be more important for the mains vs the crank. In overall life span, clean engine oil at the appropriate viscosity for what your conditions are is all you should need to worry about.

I don't think it's fair to say ACL is unproven at this point, but when I first put in a set back in 2019 they were just hitting the market. I (as well as many others) have used ACL on other engine builds. They are good bearings.

The ACL HX gives you 0.001” (0.025mm) extra clearance, what some of us do is use HX on the top and the standard one on the bottom. But you either have to build it mixed from certain shops, or do the mix on your own, but you'd have to at a minimum have 2 sets, the standard and the HX.

This is an established and accepted practice, yes it's not a perfect circle and that's ok. The thing that many don't understand is that the bearings aren't perfect half circles on purpose. When installed and under operation it's actually an oval on purpose.

[DRLane]

This is the correct answer and the backlash is why most direct knowledge disregarded participation on these forums long long ago.

Least the first half! I’m still proponent of BE.

[charliev68]

I guess my real question is why BMW decided to make their RBs so tight? There must be a reason or trade off!
It’s not like the don’t know how to mis match bearing shells to achieve certain clearances. They clearly do that for Main Bearings.

[DRLane]

Originally Posted by charliev68

I guess my real question is why BMW decided to make their RBs so tight? There must be a reason or trade off!
It’s not like the don’t know how to mis match bearing shells to achieve certain clearances. They clearly do that for Main Bearings.

There are endless threads on this across the forum. Once every 6 month someone starts one of these. Should be a banned subject for creating confusion as often times those with great knowledge are exhausted and leave thr OP with a bunch of trash comments infiltrating the thread. Use the search.

[S85 builder]

Every S engine has shown to rod bearing issues. BMW likes to go tight, is what many of us seem to conclude. For the S85/65 it's been established that their specs are tighter than "universally accepted" clearances. From a tribology aspect, the 10W60 isn't ideal with such tight factory clearances, especially on cold start and when sub 40 deg F. S85s don't have the main bearing wear issue, so it's an easier situation to deal with, and why I never personally picked up an E92 M3.

[lonatic]

FWIW I have acl bearings, supercharged for about 4k miles stepped down to 3.33 pulley full e85. No issues so far.

[CamasM3e93]

There have been very few cases (reported here) of failed aftermarket rod bearings, no matter the brand.

Those that I have seen were related to installation issues.

There have been very very few people replacing their aftermarket bearings with a second aftermarket set. So we have almost zero data on how these are wearing compared to each other, other than to say they all seem to be doing ok as a group short of failure.


In the fall, I replaced a Clevite-made VAC set with 65k supercharged miles and other than a scratch my installer felt was an installation error, they looked new out of the box. I chose BE bearings and don’t intend to ever replace them. I have no data to feel strongly about the brand decision but I value how much thought effort and design BE has put into this s65/s85 issue.

All this to say is that we really don’t know, BE versus ACL versus whomever.


Aside- I appreciate that there’s an old guard whom have been on the forum for a decade and have tired of some of these topics. But we’ve got a whole new generation of e9x m3 owners coming in and raising some of these questions on posts will happen and personally I welcome the discussions. You can always choose not to open a thread.

[deansbimmer]

Our go-to has been BE bearings for years. If in doubt, this is the way to go.

As far as ACL go, we started to offer matched and measured sets years ago when BE availability was spotty or for our friends overseas. Mporium is the only vendor I know of that actually measures the bearings to combine into sets. Furthermore, our ACL sets are WPC treated for anti-wear and are certainly the only vendor that offers them this way. Other vendors just grab the packs out of the H and HX sets and repackages them which is a huge gamble.