Z4M S54: Rod Bearings Replaced

[pal]

Last month I had Randy Forbes replace the rod bearings on my Z4MC with his coated ones. My car had 59K miles and close to 50 track days at the time and once the bearings came out, the timing of this job seemed very appropriate. The car has seen very regular oil changes (2-4 track days per change) and all oil has been analyzed by Blackstone that showed occasional high lead numbers.

Below are the pulled bearings. Disregard the sharp scratches as those were from them sitting in a plastic box and hitting each other.

#2 top was the worst for wear, followed by #3 top. #5 had an unsual slant on the right edge indicating that the bearing was possibly mounted at a very slight angle?? Discuss away.






Some of the interesting pictures I took while watching and learning from the master are below.

Positioned for its surgery.


Draining the oil in preparation for removing the oil pan.


After putting an engine support on the front of the motor the Z4MC was raised into position for its surgery.


Steering column removed from the rack and marked just to be on the safe side. Though it looked like it can only go in one way.



Removed subframe bolts - the liquid is just penetrating lube.


Rack unbolted from subframe and subframe removed and out of the way.




Pulleys loosened and power steering pump bracket disconnected


FCABS and sway bar links disconnected and sway bar removed from car. This allows the entire assembly to swing under the car to create a more usable workspace.


Draining the pan.




Dipstick and breather need to be removed from pan. Dipstick also has a nut on the top (near intake plenum) that needs to be removed.


Unbolt the seemingly infinite bolts on the pan and carefully remove it from the block and let it drain on the side.



Cleaned pan ready to go back when its time.


Oil pump and lines removed - the crank is painted blue for some reason.



Now it time to remove one rod bearing at a time (in firing order helps), clean the journals with scotch brite, apply assembly lube to new ones and reinstall.




Fresh coated set


Coated bearing on the right


Plasti guaging the new bearings takes time as they need to be installed and removed and then measured for proper clearance. This works as the new rod bolts call for 5Nm, 30Nm and 105° turn 3 times. So the bolts need to be loosened anyways.




Ready for final assembly after the plasti-guage step. They are not removed anymore.

[Randy Forbes]

Nice post PAL, the pictures turned out very good, combined with xlnt narration. The only thing I see that needs clarification, is that we didn't necessarily follow the firing order (1, 5, 3, 6, 2 & 4) but the actual pairs of "throws" on the cranshaft. Thus, we did #'s 1 & 6 together, then 2 & 5, and finally 3 & 4. It would not matter if you did #'s 1 through 6 in order, but you'd have to rotate the crankshaft twice as many times (there would be no harm in doing this).

After changing out all the inserts, I usually rotate the crank several times by hand anyways, before I put it all back together.

Good job PAL!

[inTgr8r]

Nice write up....
There is no one I'd rather have on a job like this other than Randy!

Looks like your timing is impecable
At what point(mileage) did you start getting high lead on the Blackstone samples?

Coated bearings - is this a Randy special? I'd like to hear more about them.

[Randy Forbes]

Originally Posted by inTgr8r

Nice write up....
There is no one I'd rather have on a job like this other than Randy!

Looks like your timing is impecable
At what point(mileage) did you start getting high lead on the Blackstone samples?

Coated bearings - is this a Randy special? I'd like to hear more about them.

This process has been around for quite a few years, it's actually a benefit of the technology transfer from NASA to the private sector that was initiated in the latter part of the 1980s.

I've personally been applying (and oven curing) the polymer dry-film lubricant (as well as others, with different thermal barrier/thermal dispersant properties) since 1992__nearly twenty years. I haven't built an engine without them since!

I hope that you're not in a hurry though, as I packed up my oven about three (>3) weeks ago, in preparation to moving south. Even my gray car has been shipped off (and temporarily stored in Clearwater, near the airport for any impromtu trips to monitor construction).

I'm hoping to get everything set up shortly after moving into the new digs; March 2012 is a realistic target

[pal]

Thanks for the clarification Randy and thanks for taking the time to get this done for me at such short notice

inTgr8r - the high lead readings don't appear to be related to after a specific mileage than to track events and usage style between changes. The first "high" reading (6 ppm) was at 24, 700 miles. The next 10K miles I was seeing 4 or 5 ppm, but then it dropped down to 3 after a road trip last March to Texas (and 10 - 12 standing mile runs to 150-156 mph). See below for history (all reports below 20K miles were 1ppm). At 42K I had a 7 and a 9 at 47K. It almost seems that once the numbers started to go up, they seem to settle at a higher ppm ...

I tried Greddy 10w60 for one oil change (3 track events) and it did just as well as the Castrol so may use that for a couple of changes next year.

[boondocksaint]

Good info!

[johanness]

Blue crank = v interesting. Thx for documenting ur project

[O-cha]

It's heat treated, not painted IIRC.

Did you plastigauge just to check or were you actually trying to set clearances different from the ones marked in the engine?

[JPWEraser]

Originally Posted by johanness

Blue crank = v interesting. Thx for documenting ur project

In regards to the crank, the color comes from using heat to harden the crank. The color is a function of how much heat has been cycled through the crank to harden and temper it. Coloring starts with a faint yellowing at around 425 F and turns darker yellow around 460 F. The crank will continue to change colors as the heat increases. The blue colors start to appear in the high 500 F to low 600 F range. So, the crank is blue because BMW put it in a furnace at around 600 F to harden and temper it

[pal]

Originally Posted by O-cha

It's heat treated, not painted IIRC.

Did you plastigauge just to check or were you actually trying to set clearances different from the ones marked in the engine?

Just to check.

Thanks for the info on the color guys.

[pal]

Here is a table of oil change intervals, track days on the oil against lead PPMs.

[chickdr]

Out of curiosity- what did this procedure cost?

[JCz04Bimmer]

Crap. I have about the same amount of track days and I literally just hit 59K. But I haven't been analyzing my oil. I'm curious as to the cost, as well, and how exactly did you get your NJ-based car to Randy?

[jmillet]

Originally Posted by JCz04Bimmer

Crap. I have about the same amount of track days and I literally just hit 59K. But I haven't been analyzing my oil. I'm curious as to the cost, as well, and how exactly did you get your NJ-based car to Randy?

I have my oil analysis done here:
http://www.blackstone-labs.com/
I'm at 38K miles with many, many track events and the last analysis showed elevated lead at 6ppm. Keeping an eye on it but not concerned yet.
Blackstone Oil Analysis S54 July 2011.pdf

[JCz04Bimmer]

Originally Posted by jmillet

I have my oil analysis done here:
http://www.blackstone-labs.com/
I'm at 38K miles with many, many track events and the last analysis showed elevated lead at 6ppm. Keeping an eye on it but not concerned yet.
Attachment 604696

I have the Blackstone sampling kit in my apartment... I just never remember to bring it with me when I change my oil.

I do have an oil change I need to do before it gets really cold up here in Boston and the car goes into semi-hibernation mode. I'll get a sample then and see what my lead numbers look like.

(The car is in the shop for another issue; possible leak on cylinder 6 or funky injector. Fun!)

[gcochard]

Is this at all related to the 2001-2003 rod bearing failures in the e46 m3 or is this just regular wear from track time?

[jmillet]

Originally Posted by cliffhopper

Is this at all related to the 2001-2003 rod bearing failures in the e46 m3 or is this just regular wear from track time?

Your guess is as good as anyone's. I'm sure BMW NA will say that the S54 bearing issue has been resolved.
I've heard tell that every mile driven on a HPDS road course is equal to ten miles driven on the street. I have about 4800 track miles on my Z4MC which equates to 48,000 street miles on top of 33,200 street miles which means my bearings have seen the equivalent of 81,200 miles

[pal]

The only co-relation to wear appears to be regular HPDE/track use where you spend a lot of time at high rpms.

Jared- I drove my car to Randy's and drove it back after the job was done. I would send him an instant message to get an idea of cost or IM me and I can give you a ballpark. Its not cheap but def cheaper than possibly a new motor or even a worn crank if the bearings wear through the 3 layers like they seem to be on bearing #2 on mine.

[onebluemcm]

pal- excellent write up, so nice to see a documented process like this

Randy- as I'm sure you get told all the time, nice work - what a pro. I've seen one other bottom end torn down and rebuilt, it was a 390 out of a '65 Galaxie that I had several years ago, but we pulled the engine for that job. Used the plastigauges just the same, such cool work. I've always been fascinated with the process.

It's a little concerning to me that this kind of rod bearing wear is occurring at just ~50k miles. Is it concerning to anyone else? Just thinking about it, at that rate you're quite likely looking at a major problem by the 80-100k range if they aren't changed. I guess to me it just seems, well, not right that you'd have to preemptively change rod bearings as almost a matter of routine maintenance... I am kind of felling like it's not even worth bitc#ing about because it seems to just be the plain reality of the situation with the S54, but I am none the less kind of disappointed I guess...

Also, it occurred to me to ask after reading the thread, why not look at the crank mains too? Seems like they could wear just as bad as the dang rod bearings. Obviously, much more of a job to drop the crank and reinstall on an engine still in the car, but after seeing the rod bearing wear, I'd be worried about the mains. Comments?

[onebluemcm]

Question about drain plug, relating to pics below:

Originally Posted by pal

Draining the pan.

Had my last oil change done at the dealer, was last one under warranty.....the tech said the threads in the pan seemed soft and were partly crossed. I'm not sure if they did it or if it happened during a prior oil change when the previous owner had it - not the point anyway, it is what it is.

I'm thinking of installing a time-sert insert when I do the next oil change (like this - http://www.timesert.com/ - if you don't know what it is) and my question to pal and Randy is do you think I'd be able to get into the pan enough by dropping the part with the cone shaped screen to get any and all shrapnel out from drilling and tapping for the time-sert? For obvious reasons I want to be 100% sure that there are no aluminum bits left in the pan after installing a time-sert. And if you think the time sert is a bad idea, please, let me know reasons why.

[kennyfrc]

This and other reliability issues have me looking at a new Z06. I think I'm done with german cars for a while. A 50K rod bearing life on top of the Vanos bolt and hub issues, O2 sensor failures, and other misc problems doesn't sit well with me. Who wants to rebuild their engine every 50K as part of "routine maintenance"?

Besides, GM finally fixed the seats for 2012!

[prodigal_m]

Originally Posted by kennyfrc

This and other reliability issues have me looking at a new Z06. I think I'm done with german cars for a while. A 50K rod bearing life on top of the Vanos bolt and hub issues, O2 sensor failures, and other misc problems doesn't sit well with me. Who wants to rebuild their engine every 50K as part of "routine maintenance"?

Besides, GM finally fixed the seats for 2012!

Your post just made my head hurt...you should definitely get the Z06.