[Dynamics99]

Hi,

I am at 136k Miles and currently FBO with MHD Stage 2+. I am taking care of an oil pan gasket leak and wondering if I should do the rod bearings since the bottom end is being opened up. The car's production date is 9/2010. I've read that N55s can tend to suffer from oil starvation on corners for too long due to no baffle system or secondary oil pickup. Don't know how the original owner drove but would it be worth it to replace it now? A well-known local shop is advising me to send in the oil for Blackstone analysis first. What do?

[Hoody007]

I’d do it. Your’s is an early production car without the revised oil pump and bearings (from 07/2011 on). Even my 10/2011 bearings were showing some wear - I have a low miles (70K) example with a verified BMW service history.

[whyzee125]

Absolutely do it. Search any city's craigslist and you'll find 2-3 N55's being parted out on craigslist due to a spun rod bearing, often less than 100k. It's not much more money or work to do them and you'll have the peace of mind.

[Dynamics99]

Thanks for the speedy responses! I have King Bearings STD in hand and as well as new connecting rod bolts. I'm doing this on jack stands. I will be replacing all the stretch bolts as well as the oil pump o ring.

As for the startup procedure with the assembly lube, do I have to prime the engine with the fuel pump fuse pulled out or let the assembly lube do its job?

I couldn't find much info on the min or max clearance. What would it be? I want to measure them using the plastigauge and post it on here.

[Will_460cs]

Defiantly do it - just done mine at 69K they were past their best and this was a FBMWSH car, which of course is half the problem as the oil change interval is too long.

[Will_460cs]

Originally Posted by Dynamics99

Thanks for the speedy responses! I have King Bearings STD in hand and as well as new connecting rod bolts. I'm doing this on jack stands. I will be replacing all the stretch bolts as well as the oil pump o ring.

As for the startup procedure with the assembly lube, do I have to prime the engine with the fuel pump fuse pulled out or let the assembly lube do its job?

I couldn't find much info on the min or max clearance. What would it be? I want to measure them using the plastigauge and post it on here.

The recommended is to disconnect the injectors electrically.. turn over for 10 seconds - rest for 20-30 secs and repeat 3 times.

And yes use assembly lube.. as you using no genuine bearings etc.. use plastigauge with you old bolts first.. jut to make sure your clearances are good - just one 70 degree torque is fine for this element..

remember to have on hand :

oil pump stretch bolt kit
rod bearing stretch bolt kit
sump stretch bolt kit.
Windage tray/oil pickup bolt kit
new oil pump sprocket bolt (not essential but highly recommended its a couple of quid)

A good digital angle wrench is great investment

Even with the above mark your bolts with a line so you can monitor torque.

Be wary of the oil pump bolts there are different torque specs for the different lengths

Have replacement steering rack bolts and nuts on hand ( the ones that hold the rack to the subframe)

I made a tool to hold the oil pump spoken while i torqued it, otherwise it looks a pain in the ass to do with a punch and 45 degrees angle torque.


LOTS OF BRAKE CLEAN, particularly on rod caps for cleaning!!



Also check for plastic in the sump, and check the timing gear

[wheela]

Originally Posted by Will_460cs

Defiantly do it - just done mine at 69K they were past their best and this was a FBMWSH car, which of course is half the problem as the oil change interval is too long.

Thanks for all the great info! I'm feeling a little dense with that acronym, what does FBMWSH stand for?

[Dynamics99]

Update:

I pulled the rod bearings for Rods 1,2,5, and 6. 3 and 4 require me to pull the spark plugs to relieve pressure I believe. Something I should have done from the get-go.

Pictures where they are ordered from upper to lower bearing:

Rod 1:



Rod 2:


Rod 5:

This is dirt on the bearing due to my friend handling it with his dirty hands .


Rod 6:




I think Rod 2 and Rod 6 had the worst wear. By the way, all the plastic gauge results for the Rods I have pulled so far are 0.0038mm which seems nominal. There are NO marks on the crankshaft or scoring. I have run my fingers on it. It's smooth as butter but I think I caught the wear in time.

Going to see how Rod 3 and 4 come tomorrow. I will be replacing all the stretch bolts even the oil pump sprocket.

I was struggling to do the 70 degrees twice when putting on the new bolts due to being under the car and in a tight spot. I got a digital angle torque wrench that is handy and I have lubed all the new bearings with assembly lube.

I have bruised my fingers. I wish I could disconnect the subframe completely but the steering joint cannot come free. There was so much caked-up oil on the subframe I left it to soak overnight with a degreaser. The oil pan gasket is brittle. There are no flakes in the oil pan, sump, and pump.

[fastboatster]

Perhaps trying soaking steering joint in wd40 or some other rust penetrant. Your rod bearings def look a lot more worn than mine (I replaced mine at 108k) but maybe it’s the lighting. Perhaps retake the pics with brighter light. There’s a thread for the n55 rod bearings somewhere in this section, would be good to have it posted there as well.

[Dynamics99]

Originally Posted by fastboatster

Perhaps trying soaking steering joint in wd40 or some other rust penetrant. Your rod bearings def look a lot more worn than mine (I replaced mine at 108k) but maybe it’s the lighting. Perhaps retake the pics with brighter light. There’s a thread for the n55 rod bearings somewhere in this section, would be good to have it posted there as well.

I will take some better pictures tomorrow. The bolt was easy to remove from the steering joint but the joint will not separate from the plastic fin alignment.

[Dynamics99]

Okay,

Pulled rods 3 and 4. They were in okay condition like rods 1 and 5. I have torqued them down and lubed them up. All the bolts have been replaced and angled.


I have an oil cooler that sits behind the passenger bumper.

For the oil priming procedure, I read that you have to disconnect the injector power wire. Is it easier to disconnect the red cable on the positive battery terminal?

Referring to this post here:
https://www.e90post.com/forums/showthread.php?t=1905438

[Dynamics99]

Update:

I did the rod bearings and I primed the engine 4 times. After running for about 1 minute and 15 seconds I started hearing loud knocking. It seems to be coming from the top but I'm sure that I spun a bearing or two. I drained the oil and there are no big-size chunks but a small amount of tiny flakes. I lubed the top and bottom bearings on the side that touches the crank.

When I put my hand on the fuel injector tubing I can feel it vibrate.

Also, my oil pressure during the knocking was around 41-44psi at idle.

Here is the MHD Log:
https://datazap.me/u/dynamics99/rod-...og=0&data=4-16



Should I check for bent valves, and lifters, or go straight for the rod bearings? I pray my crank is salvageable. Was priming the engine with lubed bearings, not the right choice? Could I have blocked the crankshaft galley from providing oil to the bearings?

[__G__]

Great thread, very helpful. I'm about to do the same to mine (engine out though). It doesn't sound like a happy ending! Did you get any error codes when it started knocking? No misfires?

[Dynamics99]

No error codes. I did the bearings one by one so there is no way I messed up which cap goes where. Also the top and bottom bearings cannot be mixed up due to the tang lineup.

Im going to check for piston play today. Hopefully there is no play in any of the cylinders and its just a stuck lifter. The knock sounds like its a camshaft frequency since camshaft spins half the rate crankshaft does.

For the rod bearing change you will need new:

Bearings
Connecting Rod Bolts
Assembly Lube
Oil Pump Bolts (the kit does not provide the small two front bracket bolts)
Pickup tube bolts
Oil pan gasket
Oil pan bolts


When you get to the bearings make sure you spin the crank clockwise only with a 22mm socket. I would take the spark plugs out. When you turn the crankshaft oil more oil will seep out.

And when torquing down the bearing bolts make sure you get a good grip and let them stretch for 5 mins for the first 70 degrees.

Then dont forget the prime procedure. I didnt disconnect the fuel injector power wire but i pulled out the quick release cable going to the positive terminal in the battery to cut fuel supply.

Let me know how yours come out!

[bmw335ie90]

What exactly are we calling 'bearing wear'? That pic on the second post shows mint condition bearings. All of the bearings from OP also look decent given the mileage.

N55s seem to seize from complete oil starvation not 'wear'. Go look at pictures of S54 and S65 if you want to see true bearing wear. Preventatively replacing bearings wont stop a seizure from total oil starvation.

[Dynamics99]

Originally Posted by bmw335ie90

What exactly are we calling 'bearing wear'? That pic on the second post shows mint condition bearings. All of the bearings from OP also look decent given the mileage.

N55s seem to seize from complete oil starvation not 'wear'. Go look at pictures of S54 and S65 if you want to see true bearing wear. Preventatively replacing bearings wont stop a seizure from total oil starvation.

Well,

Cylinder 1 Rod cap shot through the oil pan. Pulling the motor out and rebuilding it.

[Hoody007]

Originally Posted by bmw335ie90

What exactly are we calling 'bearing wear'? That pic on the second post shows mint condition bearings. All of the bearings from OP also look decent given the mileage.

N55s seem to seize from complete oil starvation not 'wear'. Go look at pictures of S54 and S65 if you want to see true bearing wear. Preventatively replacing bearings wont stop a seizure from total oil starvation.

Well I guess that makes me feel better about the condition of the motor - was doing my oil pan gasket and replaced them while I was in there.

Regarding the oil starvation issue, I wonder how many motors with the updated (post 08/2011) oil pump have failed.

[__G__]

Originally Posted by Dynamics99

....
Pickup tube bolts
...

Is this referring to the aluminium bolts for the windage tray/pickup tube?

I don't have these (yet) :-(

[Dynamics99]

Originally Posted by __G__

Is this referring to the aluminium bolts for the windage tray/pickup tube?

I don't have these (yet) :-(

Yes, The pickup tube bolts should come with the oil pump kit if you ordered from FCP Euro. Make sure to get the two small front oil pump bolts that bolt the sprocket bracket to the pump.

[Will_460cs]

Originally Posted by wheela

Thanks for all the great info! I'm feeling a little dense with that acronym, what does FBMWSH stand for?

Full bmw service history

[Will_460cs]

Originally Posted by Dynamics99

Update:

I pulled the rod bearings for Rods 1,2,5, and 6. 3 and 4 require me to pull the spark plugs to relieve pressure I believe. Something I should have done from the get-go.

Pictures where they are ordered from upper to lower bearing:

Rod 1:

Attachment 3210127

Rod 2:
Attachment 3210124

Rod 5:

This is dirt on the bearing due to my friend handling it with his dirty hands .
Attachment 3210125

Rod 6:
Attachment 3210126



I think Rod 2 and Rod 6 had the worst wear. By the way, all the plastic gauge results for the Rods I have pulled so far are 0.0038mm which seems nominal. There are NO marks on the crankshaft or scoring. I have run my fingers on it. It's smooth as butter but I think I caught the wear in time.

Going to see how Rod 3 and 4 come tomorrow. I will be replacing all the stretch bolts even the oil pump sprocket.

I was struggling to do the 70 degrees twice when putting on the new bolts due to being under the car and in a tight spot. I got a digital angle torque wrench that is handy and I have lubed all the new bearings with assembly lube.

I have bruised my fingers. I wish I could disconnect the subframe completely but the steering joint cannot come free. There was so much caked-up oil on the subframe I left it to soak overnight with a degreaser. The oil pan gasket is brittle. There are no flakes in the oil pan, sump, and pump.

I feel for you!! Brake clean is your friend! I hate the steering rack bolt it can be pain incoming and reattaching.

[Will_460cs]

Originally Posted by Dynamics99

Okay,

Pulled rods 3 and 4. They were in okay condition like rods 1 and 5. I have torqued them down and lubed them up. All the bolts have been replaced and angled.


I have an oil cooler that sits behind the passenger bumper.

For the oil priming procedure, I read that you have to disconnect the injector power wire. Is it easier to disconnect the red cable on the positive battery terminal?

Referring to this post here:
https://www.e90post.com/forums/showthread.php?t=1905438

Disconnect the injectors individually and I would do the coil packs too - that is from bmw technical docs and is the safe way to do it as it the only way to guarantee no firing