[miksebik]

Hi, with a little less than 100 thousand miles, I decided to change the rod bearings. Just to be sure that, the engine is safe on the bottom side. I have over 500 european horses, not as much as many of you. But still, I thought it would be a good idea. The engine worked perfectly well, no noises.
On the picture, you can see 5 bearings, 6th is not much different. The worst is 3rd bearing. My indy says it will be OK. The crank looks OK and he says that if it lasted before, it will be OK with new bearings.
What do you think? I will add the rod bearings change as a recommended measure to the thread that is here.. As I remember clearly as somebody said it was a nonsense to change it. I am not sure it is a nonsense now.

[Maniac0908]

Oooo can't wait to see. Mind posting some pics and maybe a price tag. I'm at 150k and need to start looking at this stuff

[1and1]

Have a UOA or two (or three....) prior to this tear-down?

Wear like this should have been readily apparent in the results

[08 335Ci]

If the engine is apart, I'd run a brush through the oil passages then flush them out. I'd also check and or replace the oil pump. Cheap insurance.

[eligard]

I'm not an expert, but the way it looks, might be wise to change them now.

[limitdown]

If you decide to rebuild your engine, I highly recommend ditching BMW bearings. They're soft and expensive. It's a pain to decode the exact combination of colors you need. You need to look at serial numbers on your crankshaft and crankcase, then check BMW's matrix to figure which combination you need. Some people order every single bearing possible, then return the ones they don't use.
It's better to get higher quality ones, like the coated ones from VAC.

[miksebik]

Well, I did few oil analysises and every time, all was OK. Nothing out of norm.

Of course I ordered new bearings. I know it might look like pain in the ass, from the manuals.. But we just ordered the same bearings that were on the crank (all were combination of red and yellow). The guy at BMW shop wanted to know my engine block number (which is the most most important number when determining all this) but my indy rejected looking for it and told me to just order those that were in before.

In the manual and also from an experienced guy, I knew there should be made a plastigage measuring.. to know the gap rod - bearing. From some reason, my indy said that this was not necessary. Even if we found that the gap was higher, bmw does not offer bearings that would solve this. I think he just wanted to move on. On the other hand, he rebuilt my LSD, without special tools, changed turbos without dropping the subframe... he is this kind of a guy. So I hope he knows what he is doing.

I watched the indy changing the bearings. The crank was very lightly scratched. You could feel it with your nails, but nothing bad. He said that all that should be done is a proper break-in. 2000km, when I should accelerate as lightly as possible. During this period, the new rod bearing should "get used to" the crank and it should be OK after. BTW the torque to tighten the bolts is 20Nm + 70 degrees + 70 degrees. A lot of force needed :-D

As I am from EU and the car occupies one of two jacks, it is just not possible to wait 2 weeks for some other rod bearings.

[miksebik]

BTW. Will map 6 on JB4 work, when I set it to 4 PSI max boost?

[langsbr]

I'd be very concerned if there was a big enough scratch on the crank that you could feel. Let us know how it turns out.

[miksebik]

At first, I did not feel them. Then the indy told me how to check it and when using your nail, there was little something...
Anyway, alea iacta est :-) I will flash the stock flash and start breaking in soon, I hope.

[m5james]

Bump how this turned out. GF's 08 535xiT lost it's first engine around 120k...seems that a leaking injector forced some rod knocking issues and then ultimately the engine failed when piston #1 lunched itself and the engine seized. I picked up a used 75k engine locally and it hasn't even been 10k and this ones got rod noise as well. At this point I'm looking into Ghassan or MMP rebuilt engines with their upgraded rod bearings...something I should have done in hindsight. I'd like to see if I can get away with just bearings but I haven't dropped the pan to check things either.

[THE BEAST]

I would have polished the crank.

[miksebik]

Sorry, forgot to answer.
So I really drove the first 2000km very lightly to break it in properly. Now I loaded the Trebila flash and drive normally. No change in noise, everything is OK. I repeat, that all this was done as prevention, I had no warning signals.
I also changed 3 old injectors which was a good idea as I had weird warm start-ups, sometimes. Which I do not have now.
Anyway, funny as many people said that it is not necessary to change rod bearings and that it is a stupid idea :-) You never know until you drop the oil pan.

Polishing the crank.. Maybe yes maybe no. Too late to discuss it and people who saw it live said it should be OK.

[LessIsMore]

Makes me wonder what mine look like at 120K miles ...

curious, what was labor on this job, if you don't mind saying?

[miksebik]

Hard to say, my indy said 80h for complete job that included:
- rod bearings
- oil pump cleaning and checking
- all the front&rear subframe bushings
- diff bushings
- front turbo wastegate tightening
- break fluid


I estimate that the bushings were the bigger part of the 80h job. The indy hated me for the bushings job :-D

[dyezak]

You'll be just fine. New bearings and drive forward.