[ucsbwsr]

I put the oil pan back on to examine the damage and try to draw conclusions on how the impact was delivered, at which angles and how hard, to hopefully tell us the likelihood of any potential internal damage.

From what I can tell, it looks like there was an impact from the front by how the front edge of the pan is separated and pushed reward, also there are splits branching off of that hole. The oil pump cog is bent reward in to the pump from impact and the chain is a little damaged but the to total damage to the unit doesn't seem great enough to harm the other chain driven components and structurally the pump seems pretty stout and doesn't seem to be compromised at all and certainly not the block it is bolted to.

The chain and pump from my old engine should be undamaged and can be swapped over along with my valve cover which has <10k on it, oil pan will be replaced. So as long as there damaging from the front impact making it past the oil pump then all internals should be good to go after a good cleaning/flush. Sound logic?

Would it be worth giving it a leak down test? Could I get accurate readings with the engine in this current state?

Evan






I rotated the engine to inspect the chain a bit and this was the worst of the damage, you can also see the gouges to the left of the chain where it stuck the plate.



PISTON CARNAGE

[techwhiz]

DANG!

[335is-dct]

interesting that the 335is block has additional cooling passages around the cylinders....

[ucsbwsr]

Originally Posted by 335is-dct

interesting that the 335is block has additional cooling passages around the cylinders....

I think it was a 2009+ block feature. There is a thread floating around which discussed it, I think on N54Tech

[ucsbwsr]

Cleaned the engine a bit more. The $800 N54 looks promising.

[Supra2k6]

i would have done a leakdown on the new engine before purchasing it but sounds like a good engine. The only thing that would worry me is that the oil pan cracked in the accident oil leaked out while engine was still running maybe?

[smitty513]

Evan, here's what I would do. Replace the oil pump chain guide on new engine, definetly check the crank pulley and flywheel (if it has it) for impact damage and turn engine over. With no spark plugs in it, it should spin freely. There's a BMW SIB about compression/leak down testing on N54s, I'll try to locate it. Check the cam bearings and ledges for wear, clean out vanos solenoids and check valves. Check for broken or damaged bed plate bolts. Replacing oil pump is an involving process and I can get you repair instructions if you can't find them. PM me if you have questions.

[ucsbwsr]

Originally Posted by Supra2k6

i would have done a leakdown on the new engine before purchasing it but sounds like a good engine. The only thing that would worry me is that the oil pan cracked in the accident oil leaked out while engine was still running maybe?

Ideally I would have liked to as well but considering the inconvenience to do that and also the price I was getting the engine for I was happy to do it on my own accord.

Originally Posted by smitty513

Evan, here's what I would do. Replace the oil pump chain guide on new engine, definetly check the crank pulley and flywheel (if it has it) for impact damage and turn engine over. With no spark plugs in it, it should spin freely. There's a BMW SIB about compression/leak down testing on N54s, I'll try to locate it. Check the cam bearings and ledges for wear, clean out vanos solenoids and check valves. Check for broken or damaged bed plate bolts. Replacing oil pump is an involving process and I can get you repair instructions if you can't find them. PM me if you have questions.

Thanks for the tips. I have the Bentley manual but if there is additional documentation to that I would love to see it, anything is appreciated. I tried to do a leak down test today with a Harbor Freight unit but the adapter was too large for the spark plug tunnel so I need to find another tool. I have inspected all bed plate bolts (between oil pan and block right?) and they look be all good. No damage to the block that I can tell.

While browsing Realoem I saw there is a hub connecting the crankshaft and the pulley so I plan to replace that and assume it will alleviate the wobble my pulley has and it if it doesn't, it will be obvious the crank is bent. Oil seals front and rear will also be replaced since it is convenient and good practice.

Evan

Continued to clean up the engine bay, removed the sway bar brackets and unbolted the steering rack to clean and inspect everything.


Sway bar bushings look to be in excellent condition, they only have 30k on them.


The crank pulley/harmonic balancer had a slight wobble to it.
Tilted backwards


Tilted forwards


I swapped on my old crank pulley to confirm the wobble wasn't from the pulley itself, and it wasn't.


I noticed that the 535xi pulley was noticeably larger and heavier than the 335is.


Pulleys are the same diameter


Cleaning and inspecting turbos


I have done some inspection and reached out to turbo experts to pick their brain and I decided the turbos are likely undamaged and good to go back in.


There was an oil pan bolt which broke off into the block


Prepped work area


Screw extractor and the broken bolt


Tested the hole (and others near the impact site.


Seemed like a good time to inspect subframe bushings and replace if needed, surprisingly they look great, no chunks or major cracks, only some hairline cracks on opposing sides, what appear to me as very minimal wear.

[MM Performance]

Evan,

You can remove the turbine housing vband and remove the compressor housing snap ring to remove the CHRA and get a closer look at it. Very easy to do and easy to put back together without affecting anything. Just mark your clockings with a marker but if they are VTT units since they use the stock bearing housings there should be alignment pins still in for the clockings.

I would check under the turbine heat shield for signs of oil leaking out and also on the turbine itself and turbine housing when removed and also for axial and radial shaft play of the CHRA and for ports free and clear of debris and general visual inspection for any damage.

[ucsbwsr]

Originally Posted by MM Performance

Evan,

You can remove the turbine housing vband and remove the compressor housing snap ring to remove the CHRA and get a closer look at it. Very easy to do and easy to put back together without affecting anything. Just mark your clockings with a marker but if they are VTT units since they use the stock bearing housings there should be alignment pins still in for the clockings.

I would check under the turbine heat shield for signs of oil leaking out and also on the turbine itself and turbine housing when removed and also for axial and radial shaft play of the CHRA and for ports free and clear of debris and general visual inspection for any damage.

Good info, thanks for sharing.

Evan

[ucsbwsr]

Finally got around to pulling the head off my blown motor, here are some updated pics.

Evan


You need an "extra long" T50 and T60 bit to get the main head bolts off. I didn't feel like paying a huge premium for "BMW Special Tools" or over priced bits sold locally. I ended up buying a set from AB Tools in the UK (via eBay). $25 and 8 days later these arrive. 3/8 drive which was tiny for the task of getting these bolts out but they worked flawlessly.


Head off



Cylinder #1


Cylinder #2


Cylinder #3


Cylinder #4


Cylinder #5


Cylinder #6



Took 4 pictures (quarters) of the cylinder walls on #3
#3 Cylinder Wall 1/4


#3 Cylinder Wall 2/4


#3 Cylinder Wall 3/4


#3 Cylinder Wall 4/4


Head/Valves


#1


#2


#3


#4


#5


#6


General Carnage

[MM Performance]

Everything is so mangled it's hard to tell what failed first and how it failed. 2 guess are piston split in half from detonation and the let go of the rod which just sawzall'd everything OR rod bent like crazy from to many low end pull with high torque which dropped the piston out of the cylinder which destroyed everything or just the rod broke.

What do you think failed first and how from examining everything up close? Any evidence of piston melting indicating hyperlean fuel? Do you run PI?

[ucsbwsr]

Originally Posted by MM Performance

Everything is so mangled it's hard to tell what failed first and how it failed. 2 guess are piston split in half from detonation and the let go of the rod which just sawzall'd everything OR rod bent like crazy from to many low end pull with high torque which dropped the piston out of the cylinder which destroyed everything or just the rod broke.

What do you think failed first and how from examining everything up close? Any evidence of piston melting indicating hyperlean fuel? Do you run PI?

Piston melting would show damage on both the piston and cylinder walls right? If so, it doesn't look like it melted. My very novice guess is that the piston head cracked at the same time the con rod bent. I was running TBI and pushing my Stg 2 LPFP towards it's upper limit. I will be running PI once my car is back together for more accurate fuel control.

Evan

[MM Performance]

Any of the other rods bent when you took them out? Even slightly bent?

[maaaaackle]

Damn that is some motor carnage right there. What causes this kind of catastrophic failure? Were there any warning signs that you overlooked?

[ucsbwsr]

Originally Posted by MM Performance

Any of the other rods bent when you took them out? Even slightly bent?

Haven't checked closely, I will let you know if any appear to be so.

Originally Posted by maaaaackle

Damn that is some motor carnage right there. What causes this kind of catastrophic failure? Were there any warning signs that you overlooked?

I think it was improper fuel distribution.

[muncie21]

My layman's guess is the piston shattered and lodged itself in the cylinder. The rotational inertia slammed the rod into the lodged piston, bending the rod and aerating your block. The rod definitely looks damaged from compression.

Why the piston let go is the $1MM question. From the log posted earlier, fuel trims were moderately positive and AFR was ~11/12'ish. Which seems to be ultra safe considering these motors (from the factory) tend to run much leaner than that under boost. Timing looked OK at 8-9*, didn't see any evidence of pulled timing due to knock...unless the sensors were desensitized.