Track/AX 128i Log

[spidertri]

I’ve been meaning to start a thread about my car for way too long, not for any particular reason other than to keep a log of what I’ve done with it.

After an AutoX a couple weeks ago (Feb 2025), I had a weird metallic rattle when the engine was revved to 2000 rpm. At first I thought it was my DMFW but when I got home I pulled the oil filter and found it full of metal. Videos of N5x cars with bad rod bearings sound just like my engine, so I've started looking for a replacement motor.

I'll update this thread as I work through swapping the motor, I plan on refreshing the "new" engine once I get it and preventatively replacing the rod bearings.

Due to all my mods, I run local SCCA autox in the XA class.

Car spec:
- 2011 BMW 128i
- N51 engine
- 6-speed manual
- Space Grey over black leather
- Factory options: sport package, comfort access, no sunroof

Engine:
- Euro airbox
- Silicone intake pipe
- 3IM (Not a mod but std on N51)
- MILVs
- AA Exhaust Header
- 135i Dinan axle back exhaust
- Stage FP tune - 7200 rpm limit
- Setrab oil cooler
- VAC oil t-stat bypass (stock tstat installed over the winter)
- Condor oil pan baffle

Suspension:
- Ohlins R&T w/ vorshlag camber plates
- Springs: 500 lb front, 800 lb rear
- Swaybars: E92 M3 front and rear
- 1M strut brace
- Front arms: GAS monoball tension arms and M3 control arms
- Rear arms: FCP Euro rear trailing arm monoballs, M3 upper control arms, Bimmerworld inner camber arm monoball, Manzo toe arms

Brakes/Driveline:
- Front: F30 340mm Brembo calipers and rotors
- Rear: E90 328i 42mm piston calipers, 300mm rotor
- PFC-08 pads front and rear (track)
- PFC Z pads front and rear (street)
- Brass caliper bushings in rear calipers
- Motul RBF600 fluid
- 135i Master cylinder
- Narrow hub mod in rear
- 135i N54 shift lever
- Delrin shift carrier bushings
- 22RPD DSSR
- Limitedslip.de 4-clutch ZF LSD, stock 3.23 ratio
- M3 front diff bushings

Interior/Exterior:
- Racetech RT4009W seats
- Brey-krause seat mounts on factory sliders
- Custom 4-pt roll bar
- Schroth 6-pt harness
- Rear seat delete
- 135i front and rear bumpers
- 135i gauge cluster
- Oil pressure gauge
- H5 AGM battery

Track related coding:
- Sport brakes (+spbr)
- C0F_FLR ("Engine Power Reduction to Prevent Brake Overheating") - changed from wert_01 to wert_00 and wert_02
- C0F_FBS ("Brake Fading Compensation") - changed from wert_01 to wert_00
- C0F_BB_RAB "(Ready Brake Alert") - changed from wert_01 to wert_00
- DSC: Added C0C_DBC_MIN_AUSLOESEDRUCK min_pressure 00 data value
- Diff lock off

Wheels/Tires:
- Street: 17x8.5 ET40 Apex ARC8 w/ 225/45 Vredestein Quatrac Pro
- Track: 17x9 ET52 Apex ARC8 w/ 255/40 Kumho V730 (15mm front spacer, 12mm rear)
- AutoX: 17x9 ET42 BW TA5R w/ 255/40 Bridgestone RE-71RS (5mm front spacer)

Car weight:
- Feb 2025 - 3,080 lb

Personal Best Lap times:
- CMP Full - 1:48.92
- VIR Full - 2:16.99
- Road Atlanta - 1:47.29
- CMS Roval w/ Chicanes (2023) - 1:44.30
- Roebling - Been there once and I'm sure my time wasn't very good.

[spidertri]

Random pics from events:

On track at CMP back in 2021, stock bumpers


Coming down roller coaster at VIR 2022


AutoX 2023 at ZMax in Concord, NC


AutoX 2024 at ZMax, photo courtesy of ZHPizza

[MikeroniNChz]

Oof another N51/N52 engine failure. How many track hours would you say your engine had?

[cerealwars]

Wow! Under 3100lbs. Other than seats, has anything else major been deleted to get you there? I guess that slicktop is helping too.

I'm still attacking corners on those springs you sent me. Excited to see where this thread goes.

Sorry about your N51 dude. About how many track days/auto-xs do you reckon you've done in this thing by now?

[spidertri]

Since I bought the car in 2019, I have done about 46 track hours and 22 AutoX events. The previous owner of my car did some track days with it too but he didn't go as far down the rabbit hole as I have with it.

I didn't baffle the oil pan until Feb 2024, maybe if I had baffled sooner it would have held off a little longer? Not sure, but I'm definitely planning to log oil pressure going forward and add an accusump to the system.

Otherwise, my motor did burn oil during track days, at VIR I'd add 0.5L every 2 sessions, at CMP it was 0.5L for 3 sessions. But I actively started checking the mm level of the oil to keep it as close to the 74mm maximum as possible during track days. It never burned any oil at AutoX or street driving.

For the weight stuff, yeah front seats are way lighter than stock, rear seats deleted, H5 AGM battery is a little lighter than the stock H6. The headers and my axle back weigh less than stock but I'm not sure on the exact amount, my car is pretty base spec, it would definitely be nice to take it further but I've been trying to keep it streetable so I can drive it to events (and work lol).

[MikeroniNChz]

Seems like baffled pan/accusump is a must...or the $2300 pan from bimmerworld. Good thing N52s are cheap and plentiful.

Your weight seems slightly high for your mods. Do you remember how much the roll bar weighed? You could probably save another 20lbs per side getting rid of the factory sliders.

[spidertri]

I've been looking and haven't found a cheap or good N52 yet. Went and looked at a 2013 80k mile engine the other day only to find the oil filter full of metal and chunks of plastic and metal bits in the oil pan. Definitely depends on how people maintained these cars on if you're going to find a good one.

Rollbar was about 65lb. Yeah I could go to fixed mounts for the seats, the sliders are nice but I really don't move the seats at all anymore now that the rollbar is in the back.

Hard to justify the Bimmerworld oil pan when there is almost no information out there on it. I really think the rod bearings getting spun is a cumulative thing over time and not necessarily a single event that causes it. If anything I should have replaced the rod bearings last year when I did my oil pan baffle.

Theses engines were released with extended oil change intervals and you hope the first person who owned the car actually kept the oil topped up and got it changed when the car told them to. But more likely than not, they weren't on top of keeping up on maintenance.

[MikeroniNChz]

That weight makes more sense now. Thanks for sharing.

My '09 has 20k miles so I'm less concerned with previous maintenance. But I agree with you that it's likely more of a gradual wear issue. There's a reason race engines are rebuilt after limited hours.

You could try using LKQ or car-part.com to find a new motor.

[blnk-128]

Love the thread, hate to hear about the motor. Fingers crossed on the next one!

[spidertri]

Picked up a motor last weekend. It's a 2012 N52 with about 100k on it, inside is extremely clean from what I've inspected so far.

Plan is to refresh the engine with:
- ACL rod bearings 6B1584H-STD
- AL oil pan, weld in AAF baffle and M18 Racing dipstick conversion
- Turner 18lb flywheel and ACT clutch kit
- New gaskets everywhere
- Front and rear crank seals
- Vanos bolts are the updated version already but I'm going to swap them out
- MILVs, 3SIM, headers, injectors, and accessories from my N51 (new AL bolts where required)

Need to start pulling the old motor out of the car to make it easier to swap parts over, so I'll probably get moving on that before I go too far with the new one. Ideally I'd have the car back on the road by May, we'll see if that holds up.

[blnk-128]

Sounds like a solid plan, nice that you're going from an N51 to an N52.

Any rhyme or reason you went with the ACL bearings? The shops I talked to recommended going with the WPC version of the ones you listed, I'm currently deciding which way to go.

For the oil pan, why switch to the aluminum pan if you already have a baffled steel pan?

[spidertri]

Here's my reasons for why I just went with the standard ACLs

- My engine survived from 2011 to 2019 daily driving and "some" track days. Then I bought it and started tracking and AXing it pretty frequently for another 5 years. Got to 121k mi before a bearing let go.
- Because of that, I'm probably going to treat rod bearings as a consumable and plan to change them out in some amount of time, 4-5 years?
- This ACL part number is for the N52/N54/N55/S55. If this bearing can survive in a turbo motor making way more power than we do then I think ours is a pretty conservative application.

I didn't really consider the WPC version but I haven't installed them yet so I could always return the ones I got. I like that WPC is a treatment rather than a coating, so you aren't adding thickness to an already tight bearing clearance.

As for the AL pan, I want to add the dipstick and the kit for the AL pan makes it very easy. I like that the AL pan is somewhat "structural" in that the transmission bolts to it rather than the sheet metal shield. Heat transfer from the aluminum pan should be better than the steel pan, but that could be marginal with the airflow available under there. The AL pan is a couple of pounds heavier than the steel pan, but I can live with that.

[blnk-128]

All of that makes sense to me, I'm leaning towards the WPC treatment being overkill despite what the shops say. The friction reduction is a positive, but making the bearing stronger is debatable imo. I'd rather the bearing wears than the crankshaft surface. If you're going to replace them every 4-5 years which sounds smart, that's more reason to go with the standard bearings.

I hear you on the aluminum pan likely being better for heat transfer. Does the aluminum pan have a provision that avoids having to weld in the dipstick? If you're already welding a baffle, seems like you could avoid the hassle and $ of finding a new oil pan and weld into the steel one instead.

[spidertri]

Yeah, that's a good point about the WPC making the bearings harder and less sacrificial.

Later aluminum pans have a plug where the early cars drained the PCV. M18 racing makes a kit that just screws into that bung. My N52 came with an aluminum pan so I figured I'd clean it up and use it.

A guy on the E82 track group said he's installed this kit on 8 128s with no issues. He did recommend adding some RTV around the dipstick tube where the little O-ring seals to the threaded adapter.

Engine is dirty for now, but I'll clean it up before I start moving parts over.

[spidertri]

Hit a bit of a set back last week. I was pulling the oil pan off the new-to-me motor to start looking at the rod bearings and discovered several cracks in the magnesium bed plate. I counted 7 cracks on the bearing bridges from cylinders 1-4. None on 5 and 6. The cracks are only in the magnesium, not on the ductile iron bearing seat inserts.

Obviously there is also significant bluing on the crankshaft at both the main and rod bearings, it would appear that the bearings were starved of oil at some point.

It's a pretty big bummer, this motor was really clean otherwise. I'm looking at options now to either exchange this one with the seller or find a way to fix it.

I still need to pull my old motor, it would be interesting to see if there are any cracks in that bedplate.

Just wanted to post this for awareness when looking for a good used motor. I know it's not easy or even possible to pull the oil pan/pick up tube/windage tray before buying a motor but this is another potential issue you may run into.

[MikeroniNChz]

Big oooof. At least you found it now instead of after installing it. Where'd you end up sourcing this motor from?

[MikeroniNChz]

Also curious how your fitment is with 17x9 +42 - any fender work? Is the narrow hub mod a must for rear fitment with this offset?

[spidertri]

I rolled all the fenders pretty soon after I got the car in 2019 so that I could fit the 17x8.5 with a 245 on them. The rear had to be rolled to fit that without rubbing.

17x9 et42 would stick outboard further than the 8.5 so yeah I'd say the hub mod would be necessary. I didn't try to run that size until after I did the hub mod.

[spidertri]

Motor update: I was able to exchange engines over the weekend and picked up a 2010 N52 with 110k on it that is in good shape and has no cracks in the bedplate. Luckily the original seller was reasonable to work with and willing to pull some oil pans to find a clean one.

Looking forward to getting this engine refreshed and back in the car.

[PureE92]

Any plans on changing the water pump to a n54 pump? 400watt pump should circulate the coolant better and keep the oil cooler for the Rodney bearings to be less bothered. Psa n52 cars have 2.5mm2 wiring vs n54s 6.0mm2 for power and ground. Most likely will need the Mickey Mouse house and thermostat to water pump as well.

[spidertri]

Honestly never heard of anyone doing that before, have you done it? I've never had an issue with coolant temps or oil temps since I installed the oil cooler. I think the rod bearing failed due to repeated oil starvation, not high temp oil.

[PureE92]

Originally Posted by spidertri

Honestly never heard of anyone doing that before, have you done it? I've never had an issue with coolant temps or oil temps since I installed the oil cooler. I think the rod bearing failed due to repeated oil starvation, not high temp oil.

The guy who talked to me about it on E90post (RIP) justpete was the one who gave me the idea. I ended up doing dual 19 row setrabs, csf rad and 600watt fan since mine was a 400watt(manual n52).

I had repeated high oil temps which caused my original motor to have cam ledge bearing extremely bad(flakes in oil filter housing). I figured the high oil temp could cause degradation and the rod bearings to experience wear also. (Not qualified in anyway just making a guess, please correct me anybody)