Official S65 Rod Bearing Condition Example Thread

[Pussiwillow]

Hey guys, I haven't read through much of this but this probably best place to ask, I'm from the n55 land but I just lost my oil pan threads to I'm going to take it upon myself to do the rod bearings, what a better place to ask.
Looking at acl bearings and arp rod bolts. When you guys switch out bearings. So you plastiguage the new bearing clearances? Mic the journals? What's the procedure that works best for you guys?
I appreciate any response

[DukeofAlexandria]

Originally Posted by Pussiwillow

Hey guys, I haven't read through much of this but this probably best place to ask, I'm from the n55 land but I just lost my oil pan threads to I'm going to take it upon myself to do the rod bearings, what a better place to ask.
Looking at acl bearings and arp rod bolts. When you guys switch out bearings. So you plastiguage the new bearing clearances? Mic the journals? What's the procedure that works best for you guys?
I appreciate any response

If memory serves me correctly, doesn't the N55 just use King bearings and call it a day? The S65 does have VERY similar bearing tolerances (if not nearly exact), but I didn't think custom bearings were needed for those engines due to less stroke, and lower rev limits.

If you've never done mechanical work in the realm of piston, crank, gears, etc., I would not suggest starting here. Go to a Indy shop and pay the $11-1500 for professionals to do it.

-Duke

[Pussiwillow]

Originally Posted by DukeofAlexandria

If memory serves me correctly, doesn't the N55 just use King bearings and call it a day? The S65 does have VERY similar bearing tolerances (if not nearly exact), but I didn't think custom bearings were needed for those engines due to less stroke, and lower rev limits.

If you've never done mechanical work in the realm of piston, crank, gears, etc., I would not suggest starting here. Go to a Indy shop and pay the $11-1500 for professionals to do it.

-Duke

King bearings and acl bearings are what the s55 guys run, but it seems people over in the n55 and s55 world don't diy much, I'm still digging around. A few guys I've seen that done it said plastiguage wasn't necessary if using standard bearings and journals were in spec, their excuse was, it's hard to get right with oil dripping everywhere. But I don't see that being an issue honestly.
I just see more praise for acl over others, that and BE.
Bmw uses 4 color codes on the n55/s55
Which I can acquire once the pan and windage is dropped. However, I think acl has a pretty strong name in the field.
I've done a few m52 builds, ground up, But those engines were so easy to pull, I could pull, swap bearings and do various things and back on the car in a day.
I'll plastiguage it to be extra certain.
The thing I'm concerned about with arp bolts is the potential to distort the rod end.
At 36# for the n/s55 engines, I don't see this being a case and other have had no trouble. I'm just not sure it's worth the risk for me.
I'm going to be reaching out to a few engine builders soon and having a chat with them.

Early n55 has bearing issues, mine is the refreshed version with s55 rods and bearings. They're likely fine but at 80k miles and needing to get in there anyway, I think the piece of mind is worth it, some later model n55's are spinning them still.

[IamFODI]

Originally Posted by DukeofAlexandria

The S65 does have VERY similar bearing tolerances (if not nearly exact), but I didn't think custom bearings were needed for those engines due to less stroke, and lower rev limits.

S65 actually has a much shorter stroke (75.2 mm vs. 89.6 mm).

If this post is accurate, and if the relevant dimensions are the same between the N55 and the N54 (pretty sure they are), S65 mean piston speeds at 8400 RPM are only ~5% higher than N55 mean piston speeds at 7000 RPM. That'd mean the S65 has a much more favorable rod/stroke ratio and thus lower mean piston speeds at most RPMs.

S65s in general might average more RPM in service, but N55s in general might average higher combustion loads at everyday RPMs depending on how people drive (more torque down low).

IIRC the N54 has a slightly lighter rod/piston package and a hair more bearing surface area than the S65 does. Not sure how those dimensions compare to the N55's.

Looks like there's plenty on both sides of the scale. There are probably other factors we're not considering, too. Given that, it might be hard to say which engine we should expect to be harder on its rod bearings.

[Pussiwillow]

Originally Posted by IamFODI

S65 actually has a much shorter stroke (75.2 mm vs. 89.6 mm).

If this post is accurate, and if the relevant dimensions are the same between the N55 and the N54 (pretty sure they are), S65 mean piston speeds at 8400 RPM are only ~5% higher than N55 mean piston speeds at 7000 RPM. That'd mean the S65 has a much more favorable rod/stroke ratio and thus lower mean piston speeds at most RPMs.

S65s in general might average more RPM in service, but N55s in general might average higher combustion loads at everyday RPMs depending on how people drive (more torque down low).

IIRC the N54 has a slightly heavier rod/piston package and a hair more bearing surface area than the S65 does. Not sure how those dimensions compare to the N55's.

Looks like there's plenty on both sides of the scale. There are probably other factors we're not considering, too. Given that, it might be hard to say which engine we should expect to be harder on its rod bearings.

N55 stock turbo runs out of steam north of 6k
Most of the logical guys short shift to prevent unnecessary rpm and load, but the low end torque and more likely detonation when tuned especially lower rpm higher load is what sparked this.
Early n55 had rod bearing issues, bmw changed over to the s55 rods and bearings later.
I don't see much issue in the s55 pages, but it's still in the back of my head everytime I drive even tho I'm veryyyy meticulous about maintenance and logging etc to make sure I'm doing my part.
I like seeing the math come out ha

[Helmsman]

Originally Posted by Pussiwillow

N55 stock turbo runs out of steam north of 6k
Most of the logical guys short shift to prevent unnecessary rpm and load, but the low end torque and more likely detonation when tuned especially lower rpm higher load is what sparked this.
Early n55 had rod bearing issues, bmw changed over to the s55 rods and bearings later.
I don't see much issue in the s55 pages, but it's still in the back of my head everytime I drive even tho I'm veryyyy meticulous about maintenance and logging etc to make sure I'm doing my part.
I like seeing the math come out ha

Guys, as title says this is a s65 bearing thread, pls clean this up and start a separate thread...

Thanks

[Alexand3r]

Because my engine blew(cylinder 5 damage) and I took it apart, I got a chance to take a look at the BE rod bearings, that I have installed around 25 000km ago, of which quite a lot of tracking. Oil wise, I have been using mostly RedLine 5w50 with some changes with Ravenol and Liquy Moly. I have been doing oil changes frequently. Sorry for the crappy photo, but you get the point

[TX]

Originally Posted by Alexand3r

Because my engine blew(cylinder 5 damage) and I took it apart, I got a chance to take a look at the BE rod bearings, that I have installed around 25 000km ago, of which quite a lot of tracking. Oil wise, I have been using mostly RedLine 5w50 with some changes with Ravenol and Liquy Moly. I have been doing oil changes frequently. Sorry for the crappy photo, but you get the point

Thank you for making me not regret reading the last page tonight. Good photos thanks man and great looking shells!

[Green-Eggs]

Originally Posted by Pussiwillow

I just see more praise for acl over others, that and BE.

I always see praise for BE as the standard everybody compares to. I see praise for ACL saying "it's not as good as BE, doesn't measure every shell like be, doesn't create matched sets like BE, doesn't offer a warranty like BE, but it's good enough -- especially for 1/4 the price."

[Helmsman]

Originally Posted by Pussiwillow

N55 stock turbo runs out of steam north of 6k
Most of the logical guys short shift to prevent unnecessary rpm and load, but the low end torque and more likely detonation when tuned especially lower rpm higher load is what sparked this.
Early n55 had rod bearing issues, bmw changed over to the s55 rods and bearings later.
I don't see much issue in the s55 pages, but it's still in the back of my head everytime I drive even tho I'm veryyyy meticulous about maintenance and logging etc to make sure I'm doing my part.
I like seeing the math come out ha

Hey man, glancing back I realize I came trough a bit stiff which wasn't my intention, me being a structure fascist... my advice meant to be a separat thread for the N55 will probably gain better response. We love rod bearings on this board...

[jvictormp]

Originally Posted by Alexand3r

Because my engine blew(cylinder 5 damage) and I took it apart, I got a chance to take a look at the BE rod bearings, that I have installed around 25 000km ago, of which quite a lot of tracking. Oil wise, I have been using mostly RedLine 5w50 with some changes with Ravenol and Liquy Moly. I have been doing oil changes frequently. Sorry for the crappy photo, but you get the point

Fuck!!! I just finished a long journey replacing my engine due to cyl 5 damage too. What happened??

In case you didn't see, check it out:

https://www.m3post.com/forums/showthread.php?t=1851485

By the way, those are lower bearings, right?

We would love to see the upper ones.

[recentfuture]

100k full service + RB, TA & FBV swapped. Along with plugs coils fluids belts brakes rotors control arms valve cover gasket engine mounts etc. got a steal on the car but the previous owner was a pathetic owner. Almost no maintenance.

[DukeofAlexandria]

Originally Posted by recentfuture

100k full service + RB, TA & FBV swapped. Along with plugs coils fluids belts brakes rotors control arms valve cover gasket engine mounts etc. got a steal on the car but the previous owner was a pathetic owner. Almost no maintenance.

Are you...are you sure that engine wasn't hydro locked or spun bearings....

Because those look a lot like hydro locked or spun bearings...like, have you actually been able to crank the engine....wtf did the journals look like if those were the bearings!?

-Duke

[AndyW]

I just got my first E93 M3. This thread gives me hives...lol.

[DrFerry]

Originally Posted by recentfuture

100k full service + RB, TA & FBV swapped. Along with plugs coils fluids belts brakes rotors control arms valve cover gasket engine mounts etc. got a steal on the car but the previous owner was a pathetic owner. Almost no maintenance.
[IMG]https://www.m3post.com/forums/attach...8;d=1643290877[/IMG]

Those shells are some of the worst I've ever seen. Perhaps worse do exist, but yours may take the prize for worst example on this thread. You're a lucky guy. You ought to go to Vegas and play the tables. Looks like you'd be good at it.. Just kidding and thanks for posting.

[recentfuture]

Originally Posted by DukeofAlexandria

Are you...are you sure that engine wasn't hydro locked or spun bearings....

Because those look a lot like hydro locked or spun bearings...like, have you actually been able to crank the engine....wtf did the journals look like if those were the bearings!?

-Duke

She drives like a champ now. Crank was fine too. These were off cylinder 1, rest were nowhere near as bad. I almost fainted when I saw these LOL.

[Assimilator1]

Lol! Don't blame ya!

Originally Posted by Alexand3r

Because my engine blew(cylinder 5 damage) and I took it apart, I got a chance to take a look at the BE rod bearings, that I have installed around 25 000km ago, of which quite a lot of tracking. Oil wise, I have been using mostly RedLine 5w50 with some changes with Ravenol and Liquy Moly. I have been doing oil changes frequently. Sorry for the crappy photo, but you get the point

Uppers or lowers? Makes a big difference!
(Btw, it's actually a fairly decent photo , just missing that ^ info)

[stefan_e36]

Originally Posted by Assimilator1

Lol! Don't blame ya!



Uppers or lowers? Makes a big difference!
(Btw, it's actually a fairly decent phoot , just missing that ^ info)

+1 very interesting....

[its55]

Originally Posted by AndyW

I just got my first E93 M3. This thread gives me hives...lol.

Me too

[IamFODI]

Originally Posted by AndyW

I just got my first E93 M3. This thread gives me hives...lol.

It's not all bad! This thread posted clear evidence that the updated BMW bearings aren't wearing nearly as badly as everyone thought they were – maybe not badly enough to merit concern. Far better than the originals at least (basically never down to the copper).

[Assimilator1]

Ooo never's a strong word!

I think, maybe, possibly this is the 1st instance I've seen of an LCI bearing possibly showing copper that I've seen (top, no7). Atm he hasn't done the little experiment on that shell.
But anyway, largely agree that the LCI bearings fair far less worse.
I think if I had an LCI engine I would probably still change them anyway, but it would be much less pressing.

Originally Posted by Fezza

Assimilator1 did your test on two of my worst LCI shells (59k miles) and it cleaned up to the Tin layer, 2nd shell I went further until Copper showed up.

Nice one, thanks for that , sorry for the delayed reply, it seems the tagging didn't work, I got no notification AFAIK, weird!
That shell on the right, I take it showed tin before you hit copper?
Which number shells were they?

Originally Posted by nicke_1

I guess that you mean cyl #7, top bearing (once again, sorry for the bad picture, a new one has been uploaded - see my previous post). Measured the play for the old bearings for cyl # 4 and 5. For cyl #5 I got 0,051mm for the old bearing and 0,038mm for the new BE Bearing... Wired. I'm going to remove it tonight and do a new measurement. Good thing that I choose reusable ARP-bolts...

Ah yes, no7 not 4, your original pic hid the correct number .

Re plastigauge, between old and new bearings, did you use it at close to the same temperature as each other?
Btw, do you fancy doing a quick little experiment on your no7 shell? (Like Fezza did above with the left shell).

[IamFODI]

Originally Posted by Assimilator1

Ooo never's a strong word!

Hence the modifier "basically".

If you want more precise wording: "seemingly as unlikely as any other freak occurrence in an engine."