[AmuroRay]

Have you tried the M2/3/4 GTS temp sensor kit? I know bimmerworld sells it. It allows a reading for overfill and allows more oil capacity. No idea if it works on a Non M though.

[AbbeyRoad]

Originally Posted by AmuroRay

Have you.....

I've never owned nor worked on a BMW before last year.

[AbbeyRoad]

Almost ready to bolt down the crank!

Below is my bearing order from raceeng.com. The mains are 235°-ish groove by my measure. The rods are normal King bearings with an aftermarket coating.

This is a different block -- I was concerned about the oversize on cylinder 5. Lucky there was a good one at a local scrapper: $500 ouch.

Blue-print:
Crank runout 0.002"
Crank end play 0.004"


=-=-=-=-=-=-

CALICO COATED KING ROD BEARING: BMW N54/55(6 CYL SET) - CAL-CR222SV-STD-6

CAL-CR222SV-STD-6

$167.50

ACL RACE MAIN BEARING: BMW 3.0L N54/N55 - STD(SET-6 CYL) - 7M1397H

AC-7M1397H-STD

$271.95

[yupetc]

Well done AbbeyRoad. I'm down here in Houston, TX. I'm a manufacturing engineer and have been tinkering with BMW's for over 10 years now, I started out with N18 motors on Mini Cooper S, then N52, then A LOT N55's, now B58. The last 5 years I was mainly building forged internals, rebuilding stock motors since I got bored from all the COVID work from home break. I've done over 30 N55 motors so far and more than half of them are EWG versions, not that it really makes too big a difference. Anyway, I just want to say that I've watched most of your Youtube postings so far and you're pretty much on point, and being extra cautious, which is great. I can't say I agree with drilling the holes out of that oil pump, but maybe your trial will lead to something new. I'll state for the record that these N55's are "temperamental" motors in my opinion. I've gone through 4 of these motors on my own X5 tuned with FBO mods and forged internals.

And just to put it out there, since I've done quite many rebuilds so far, I have the authority to say that these oil pumps may work well enough, but oil starvation IS the main cause of catastrophic rod bearing failure, almost 100% of time. The only 2 motors I come across which had rod bearing seizure were of flooded motors where water got into the motor and there's hydro-locking. And one of the hydro-locked motors has the oil pump completely ganged by water in that oil pump (Newtonian fluid). The moment I relieved that oil pump, water poured out, the crank was able to rotate freely except the #2 and #5 rod bearings were toast, I saw heat signatures on those copper-tin layers where soft babbits are completely gone, and whatever is left of the bearing shell basically welded onto the crank journal.


For all of you out there, oil starvation on an N55 is real, though millions of motors may not go through this, those who are quite seriously modded and drive with a lot of G's may realize how serious this problem gets. One may get lucky at times, but almost always, these motors CAN suck up empty space and there goes your bearing.

Another big point which was talked about by other posts here, which I agree with, is that oil service intervals need to be kept short. That whole CBS from iDrive will get you in deep shit and leave you stranded on side of the road if you're solely relying on it. I pretty much use the iDrive's oil level measurement feature when I go to a car wash, only to let the sensor read oil height. If it's not green, I'd keep it filled up to about 7-quarts total always. What I've learned from the N55's is that you need to constantly (at least once a month) check oil level, and change that oil between 3,500 to 5,000 miles. Do not wait for 10k mile or whatever that CBS says. That'll keep your oil clean and constantly checked for level.

These motors are also VERY prone to have gasket leaks. Valvecover, busted PCV (oil goes into intake tracts), front main seal, rear main seal, turbo plumbing, Oil filter housing, oil pan, etc.. These some leaks can lead to rapid oil loss where the oil sensor doesn't pick up soon enough. So you must take great care and address leaks as soon as you discover it. Good luck with Oil pan and rear main seal leaks, those will require motor to come out of the subframe and/or remove the transmission. Also with oil filter housing gasket replacement, the 3 bolts that secure the heat exchanger to the housing need to be accounted for, one of them is a shorter bolt and if you mixed up the bolt locations, you'll have one side installed loosely, and it takes less than 5 miles for oil to spew out completely and there goes your bearings again.

I've at once pieced together a kit to install the double suction S55 oil pump onto the N55, but upon mating it to my transmission is when I realized my oil pan cover was made for manual transmission. I couldn't secure it to my auto transmissions torque converter bolts that way. The only way to do this is to remove the oil pan, mate the block to the transmission first, then re-install the oil pan. But then next time if there's anything I need to do to dismantle the transmission, I'd have to undo the oil pan first in order to access the torque converter bolts. Since then I've given up the S55 pump kit and sold it. Nowadays I just learn to check oil level weekly while car pass through a carwash. Just enough time to read 100% and know what height the oil is. I noticed the harder I drive the car, the quicker the oil loss; sometimes a quart per 2k miles. That's enough to close this entire conversation if I don't check it enough and drive 5-6 thousand miles blind and half the oil's gone.



Whoever comes forth saying there aren't any oil starvation problems with an N55, clearly you either don't know what you're talking about or you're simply poorly learned and researched on these motors. I wouldn't call it a "design flaw" by BMW, but I'd be confident enough to say that by the way this motor runs, there are a few solid ways to mix up a perfect storm and toast those bearings.

And 5w-50 oils may appear a bit thick, yes, but if you know your own build and draw some intel from the way your bearing clearances are set, doing 5w-50 may be the smarter move to close the gap and keep that film intact to levitate the rods from the journals. All this misunderstanding that you must use the colored shells from BMW OEM parts are just naive. I've ran King's, ACL,s, Calico-coated, and iRox coated aftermarket bearings, and they all seemed to perform better than OEM's 2-layer crap. The coated bearings give you an extra protection when shit goes south, to an extent of how many more revs you can put it through. But OEM bearings simply will seize and weld onto the journal more than any coated aftermarket tri-layer performance bearings. So yeah, these aftermarket bearings DO perform better even during an oil starvation event; but after all, when all oil's gone and the film's lost, no bearing or coating will save your rods; except coated bearings will have you spinning a bit longer, overheat maybe, but less likely going straight for seizure and welding up to the journal.

[LA1Z24]

Originally Posted by yupetc

I've at once pieced together a kit to install the double suction S55 oil pump onto the N55, but upon mating it to my transmission is when I realized my oil pan cover was made for manual transmission. I couldn't secure it to my auto transmissions torque converter bolts that way. The only way to do this is to remove the oil pan, mate the block to the transmission first, then re-install the oil pan. But then next time if there's anything I need to do to dismantle the transmission, I'd have to undo the oil pan first in order to access the torque converter bolts. Since then I've given up the S55 pump kit and sold it. Nowadays I just learn to check oil level weekly while car pass through a carwash. Just enough time to read 100% and know what height the oil is. I noticed the harder I drive the car, the quicker the oil loss; sometimes a quart per 2k miles. That's enough to close this entire conversation if I don't check it enough and drive 5-6 thousand miles blind and half the oil's gone.

I have that pan bolted up to an automatic transmission. The S series pan is the same between auto and manual. The 'auto' that pan comes with is a DCT though.

To install that pan on an automatic, Intake manifold off, starter out, crank position sensor out. Tekton 3/8" drive 18mm swivel socket. Worked great for me.

[yupetc]

Originally Posted by LA1Z24

I have that pan bolted up to an automatic transmission. The S series pan is the same between auto and manual. The 'auto' that pan comes with is a DCT though.

To install that pan on an automatic, Intake manifold off, starter out, crank position sensor out. Tekton 3/8" drive 18mm swivel socket. Worked great for me.

Yea that was the thought process I had at that point but I still gave up because if I ever had to deal with those bolts again with engine in the bay, my fragile spine wouldn’t last long bending and trying to get within torque in that little bitty space that’s left. And I’ve also had incidences where torquing against a locked timing plate did “bend” the flywheel at once. Result was some annoying chatter and vibration. So that’s why I didn’t go for it. But yes, the S55 oil pump with double suction is the best way to go. There are other aftermarket options available in the latter years but I didn’t want to do those because at some point if I have the sell the car as-is, I just don’t want to sweat the next owner with parts that they just can’t locate or figure out easily.

[AbbeyRoad]

Originally Posted by yupetc

Well done AbbeyRoad. I'm down here in Houston, TX. I'm a manufacturing engineer and .......

Very interesting, thanks.

You are correct: drilling a hole in the oil pump (and/or flipping the piston) is a bad idea.