DIY: S65 M3 Rod Bearing

[pbonsalb]

I would try ACL. Maybe a mixed set if available.

https://www.mpowermotorsports.org/online-store

https://store.langracing.com/acl-rod...mw-e9x-m3-s65/

[SAMM3Y]

Originally Posted by tdott

Did you read any of this before deciding on AR625?
http://wiki.rcollins.org/core/index..../S85_Rod_Bolts

60ft-lb they produce bore distortion.


"ARP-2000 rod bolts are also available from BE Bearings. We call these BE-ARP. These bolts for S65/S85 are custom made by ARP for BE Design (aka BE Bearings). The BE-ARP rod bolts have been thoroughly tested at different torque ratings to ensure the best setting to match OEM clamping force with minimum bore distortion. ARP does not manufacture and sell these bolts to the public. You can only get these through the BE Bearings web store @ http://www.bebearings.com/store, or a BE Bearings reseller."

That's a lot of decimal places on that scale, we are talking about the difference of 5/10,000"? I think following the manufacturer recommendations of properly stretching the threads to reassure they don't come loose at 7000 rpm is the right path to choose if your gonna use the 625's.

[tdott]

Originally Posted by SAMM3Y

I think following the manufacturer recommendations of properly stretching the threads to reassure they don't come loose at 7000 rpm is the right path to choose if your gonna use the 625's.

and how are you going to measure stretch with the s65 rods?

Those decimal places directly correlate to the range of clearance, it can put parts of the rod clearance too tight and other parts too loose, it also effects oiling if the clearance is not consistent.

[SAMM3Y]

Originally Posted by tdott

and how are you going to measure stretch with the s65 rods?

Those decimal places directly correlate to the range of clearance, it can put parts of the rod clearance too tight and other parts too loose, it also effects oiling if the clearance is not consistent.

You can't measure stretch my point is I'm not gonna leave them loose like that scale implies by showing the increase in bore distortion with the increase of torque. I used the 625's because of availability at the time and if your bearings have extra clearance being concerned about a few 10 thous of "bore distortion" measured by who knows who in who knows what environment is impervious.

[tdott]

Originally Posted by SAMM3Y

You can't measure stretch my point is I'm not gonna leave them loose like that scale implies by showing the increase in bore distortion with the increase of torque. I used the 625's because of availability at the time and if your bearings have extra clearance being concerned about a few 10 thous of "bore distortion" measured by who knows who in who knows what environment is impervious.

OEM Nominal Rod Bearing Clearance is 0.00150 inch
BE Nominal Rod Bearing Clearance is 0.00235 inch

Chart shows ARP625 at recommended torque rating can be upto 0.0004" off/distorted. That is ~26.7% of stock bearing clearance.

IMO that is not insignificant.

[pbonsalb]

Read the post by Green-Eggs in this thread. He uses ARP 625 when he can’t get BE ARP. Says 625 are good but more expensive. He may be using an alternative torque spec — I don’t know.

https://www.m3post.com/forums/showthread.php?t=1624741

[Helmsman]

Originally Posted by pbonsalb

I would try ACL. Maybe a mixed set if available.

https://www.mpowermotorsports.org/online-store

https://store.langracing.com/acl-rod...mw-e9x-m3-s65/

+1/3rd of BEs price.

[dty3]

I just had my rod bearings done. 2008 e92 with 48,000 miles...
I used ACL bearings and ARP Rod bolts.
on almost all my top bearings, it was already into the copper layer....
on the bottom bearings 2 were showing copper at the edges...
Since the rob bearing job, the engine has been noticeably quieter at
start up and while it s running..

Thank you Perry and Scott for recommending Perry...

[Helmsman]

Originally Posted by dty3

I just had my rod bearings done. 2008 e92 with 48,000 miles...
I used ACL bearings and ARP Rod bolts.
on almost all my top bearings, it was already into the copper layer....
on the bottom bearings 2 were showing copper at the edges...
Since the rob bearing job, the engine has been noticeably quieter at
start up and while it s running..

Thank you Perry and Scott for recommending Perry...

Sounds like nice timing mate. ACL standard or HX used?

[Pig Farmer]

Just another data point... I too replaced my RBs with ACL Bearings. I bought a set of both the 8B150H-STD (standard) and 8B1580HX-STD (extra clearance) bearings and made a mixed set. I measured each bearings thickness at 90 degrees from the parting line and they were very consistent (+/- 0.0005mm). The engine does sound/feel a bit smoother after the install, but it could just be the fresh oil. I changed the oil after 400 miles and sent a sample to Blackstone for peace of mind. I didn’t expect to see anything unusual with only 400 miles on the oil (unless I seriously f*cked up the install) and was pleased to see zero lead. I now have 1000 miles on the ACLs and the engine is as happy as ever.

[Helmsman]

Originally Posted by Pig Farmer

Just another data point... I too replaced my RBs with ACL Bearings. I bought a set of both the 8B150H-STD (standard) and 8B1580HX-STD (extra clearance) bearings and made a mixed set. I measured each bearings thickness at 90 degrees from the parting line and they were very consistent (+/- 0.0005mm). The engine does sound/feel a bit smoother after the install, but it could just be the fresh oil. I changed the oil after 400 miles and sent a sample to Blackstone for peace of mind. I didn’t expect to see anything unusual with only 400 miles on the oil (unless I seriously f*cked up the install) and was pleased to see zero lead. I now have 1000 miles on the ACLs and the engine is as happy as ever.

Nice, and what clearance do you expect with the mixed set?

[pbonsalb]

The average DIYer can’t measure. You would need a rod out of the motor. Lang Racing does the mix and match and gives the spec it has actually measured under the description tab:

https://store.langracing.com/acl-rod...mw-e9x-m3-s65/

[Helmsman]

Originally Posted by pbonsalb

The average DIYer can’t measure. You would need a rod out of the motor. Lang Racing does the mix and match and gives the spec it has actually measured under the description tab:

https://store.langracing.com/acl-rod...mw-e9x-m3-s65/

Understood its not possible to measure but would assume expectations on the clearance span based on the shell mix. According to ACL their HX gives a ~ 0.039-0.083mm with a "average" of 0.063 (0.0025inch). Anyway, just curious on what target clearance he had.

Ps. Find it hard to believe Langracing have "designed" their own spec for ACL, as well as that the mix set could provide suggested 0.0023-0.0025inch clearance.

[dty3]

HX sir..
Pig farmer, where in FL are you?...

[tigermack]

Originally Posted by Barish76

At 9 installs I would say your a pro at it. Too bad BE bearings are out of stock when I talked to the guy at BE last week.

There's a vendor on here that has the best pricing around and they are in stock. I got mine within a week. Abdul offers special pricing to forum members.

https://www.m3post.com/forums/showthread.php?t=1511267

[deansbimmer]

A word of caution to those considering mixing ACL H and HX shells to mimic BE clearances. Be aware that ACL, like most manufacturers, measure and bin their shells to achieve sets that fall within their specified combined clearance. As a result, we've seen a significant amount of HX shells measure the same as H shells, and vice versa.

As a result, one cannot simply buy the two sets, blindly mix the shells, and assume that they've just created the ideal "extra clearance" set. They need to be individually measured, and the typical micrometers are not precise or consistent enough for that task. A proper drop mic and stand are required (shown below), and is similar to the setup used by BE and other qualified engine builders. We match them this way, and the set sold by Lang would likely fall into the category of properly matched sets.

[SYT_Shadow]

Originally Posted by deansbimmer

A word of caution to those considering mixing ACL H and HX shells to mimic BE clearances. Be aware that ACL, like most manufacturers, measure and bin their shells to achieve sets that fall within their specified combined clearance. As a result, we've seen a significant amount of HX shells measure the same as H shells, and vice versa.

As a result, one cannot simply buy the two sets, blindly mix the shells, and assume that they've just created the ideal "extra clearance" set. They need to be individually measured, and the typical micrometers are not precise or consistent enough for that task. A proper drop mic and stand are required (shown below), and is similar to the setup used by BE and other qualified engine builders. We match them this way, and the set sold by Lang would likely fall into the category of properly matched sets.

Some apparently are happy imagining they are matching BE bearings by mixing and matching without measuring.

Facepalm

[Scharbag]

I just do not get why people want to save $300-$400 dollars on their bearings instead of buying BE. I understand that BE inventory can be a bit of a problem, but lots of people seem to just think there is no value in buying a set of hand measured shells that ensure the best possible clearance...

Seems funny given it takes 8 hours minimum to change them. And a "new" engine is $12-$15K installed.

If it is engine out, and you select the shells to exactly meet your clearance target, then use OE, VAC, King, ACL etc. The quality of the material is not in question. The clearance is. Why chance it where there is so much good scientific information available? I just do not get it.

Oh well, my saddle horse has died...

[SYT_Shadow]

Originally Posted by Scharbag

I just do not get why people want to save $300-$400 dollars on their bearings instead of buying BE. I understand that BE inventory can be a bit of a problem, but lots of people seem to just think there is no value in buying a set of hand measured shells that ensure the best possible clearance...

Seems funny given it takes 8 hours minimum to change them. And a "new" engine is $12-$15K installed.

If it is engine out, and you select the shells to exactly meet your clearance target, then use OE, VAC, King, ACL etc. The quality of the material is not in question. The clearance is. Why chance it where there is so much good scientific information available? I just do not get it.

Oh well, my saddle horse has died...

Some people seem literally obsessed with proving the unprovable. With explaining that regular production tolerances are 'good enough' vs 100% inspection.

It blows my mind. Really.

As I don't pull engines when doing rod bearings I won't do a job unless it uses BE bearings.

[pbonsalb]

Is it any worse than the 90% of owners with original stock bearings who are accepting production tolerances as good enough? How many non BE aftermarket bearings have failed? Not any that can be blamed on the bearing.

I would trust myself to measure bearings. But for less than the $340 cost of two sets of ACL — standard plus increased clearance to mix and match — I could buy just one $250 set from Lang that has already been done. I trust Lang. Plus, it’s less work.

BE is also very good. They offer a good service at a premium price to those who want or need it. But there are other options. One shop has done hundreds of bearing changes with VAC and never had an issue. Others have done many with stock or wpc treated stock and had no issues. ACL has just started to gain some popularity for S65 bearings, but is a highly respected bearing maker. One shop that posts here gave its view on ACL last year:

https://www.m3post.com/forums/showthread.php?t=1504908

[deansbimmer]

We use ACL mixed sets in our shop when possible. Most owners have been beaten over the head for so long with BE's excellent marketing that in many cases we end up unable to book the jobs unless we have the BE's for it. Customers would rather wait than use an alternative bearing choice.

In our shop we talk with every customer about their M3 during their rod bearing service (or any service). As it turns out, maybe around 3 out of 10 are active on any social media or forum. It makes it very obvious that the few we see talking online about bearings are only a drop in the bucket compared to those out there who are still dealing with rod bearings under radio silence.

[Scharbag]

Originally Posted by pbonsalb

Is it any worse than the 90% of owners with original stock bearings who are accepting production tolerances as good enough? How many non BE aftermarket bearings have failed? Not any that can be blamed on the bearing.

I would trust myself to measure bearings. But for less than the $340 cost of two sets of ACL — standard plus increased clearance to mix and match — I could buy just one $250 set from Lang that has already been done. I trust Lang. Plus, it’s less work.

BE is also very good. They offer a good service at a premium price to those who want or need it. But there are other options. One shop has done hundreds of bearing changes with VAC and never had an issue. Others have done many with stock or wpc treated stock and had no issues. ACL has just started to gain some popularity for S65 bearings, but is a highly respected bearing maker. One shop that posts here gave its view on ACL last year:

https://www.m3post.com/forums/showthread.php?t=1504908

100% agree that if you are using a verified mixed set of ACL bearings, you are getting excellent bang for your buck. But, given the fact that ACL has an acceptable manufacturing tolerance (as highlighted by Deansbimmer), the average Joe who simply buys H and HX ACL bearings is still risking less than optimal clearance.

Based on the information provided by lots of very smart engine builders, I fully agree that a mixed set of ACL-H/HX shells should provide you with a great solution. This is borne by the numbers below:

088/089: 0.00029 - 0.00103 "/" (yikes... )
702/703: 0.00056 - 0.00098 "/" (best case almost meets suggested minimum )
ACL-H: 0.00078 - 0.00115 "/" (decent alternative)
ACL-HX: 0.00117 - 0.00161 "/" (risk of being too loose)
ACL-H/HX: 0.00098 - 0.00138 "/" (simple average - let me know if this is wrong - excellent alternative based on these clearance values)
VAC Clevite: 0.00078 - 0.00108 "/" (good option)
BE: 0.00088 - 0.00137 "/"

But given the comments provided by Deansbimmer regarding the H and HX shells being similarly sized due to tolerances, it is best to verify the ACL shells prior to use. This is something that I would bet very few shops actually do and it would suck to go through all of the work to change the bearings to not actually address the clearance issue. At least with BE shells, the binning is done for you by BE. If it is the case that Lang Racing bins the ACL shells too, then that is another fantastic option for the S65 community.

Regardless, it is awesome that we have options today. Luckily, when I bought my M3, BE was already available (ACL was not). As a DIY guy who does not own any fancy doo-dads to measure shells, I personally feel it was well worth my $ to remove as many variables as possible.

And after reviewing the numbers above, again, I am still flabbergasted by people who still choose to put OE bearings back into their S65.

Cheers and sorry for thread jacking this SYT... I promise to stop.