Rebuilding a blowed up 335is

Aaron

Lieutenant
Nov 3, 2016
533
Colorado
2013 335is 6MT

Purchased at 30,000 miles, went FBO, full e85, 470whp/512wtq at the same time. No real unexpected issues up until now, just the typical N54 stuff. Took it to a track day at 52,000 miles. v8bait made me a track tune that came on more linearly, made HPFP less sad, and ran a bit more conservative in boost and timing. But ask any racer, and real racer, and he'll tell you it's all about the tune. So fuck v8bait and his pussy track tune, I ran the more aggressive daily tune #becauseracecar

Well ambient temps were low, 50*, so coolant and oil temps stayed perfect all day as I beat the everliving shit out of the car. Then coming off a corner engine ran rough, lots of smoke, check engine light, #n54lyfe. Engine runs but runs really rough, heavy oil smoking, limp mode. Drove it home plus another 200 miles like this. Cylinder 6 misfire. Spark plug on #6 is all black covered in oil, the other 5 look perfect. Disconnecting #6 injector makes engine run more rough.

Hypothesis so far is I melted #6 piston. So engine comes out for a cheap rebuild. Here's where I'm at so far. Thankfully I've got the man's transmission and man's RWD. The automatics, and the AWD, make pulling and dropping motors significantly more difficult. Cradle wont have to be dropped, no axles to pull, no driveshaft to pull, no trans cooler in the way, and no trans lines to get in my way. VRSF downpipes also help as I dont need to worry about breaking the damn downpipe studs. On a side note, the VRSF bolts/nuts still rust and seize, I broke 1/4 on removal. I'll replace all 4 with stainless hardware.

So far I've made huge progress in a month and a half. I got the bumper cover off, and almost got the intake manifold off. So stay tuned because I move fast.
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doublespaces

Administrator
Oct 18, 2016
7,206
AZ
Excellent, at this rate you'll be done when fossil fuels are a collectible. So what are the intentions here, just replace with stock parts?
 

Aaron

Lieutenant
Nov 3, 2016
533
Colorado
Hey fuck you and the horse you rode in here on! Just for that I removed the coil wiring today.

Haha I've been slacking because they just bought me a new twin turbo company car, and I've been riding my bike since weather is good.

My budget isn't super high, and honestly I've been happy with the performance of the stock turbos. And I haven't seen any aftermarket twin setups that I like. So for the time being, the plan is to replace the piston with an OEM one, new rings, and new bearings down low and slap it back together.
 
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Reactions: doublespaces

Aaron

Lieutenant
Nov 3, 2016
533
Colorado
Pulled out the fan, disconnected power steering lines, evacuated and disconnected A/C, disconnected charge piping, removed half of the bell housing bolts, and removed 3/4 of the engine mount bolts. A big bravo to BMW, putting the underside cross brace directly underneath the last engine mount bolt.

Everything is going smoothly this far, but I've pulled enough of these that I pretty much know exactly where to go. I'll probably evac the coolant and remove the intake manifold and the rest of the bell housing bolts on Tuesday.
 

brandon818

New Member
Mar 12, 2018
9
Why do you think piston 6 melted? you claim temps were fine, but maybe you didn't check? how long were you beating on it prior to this happening?
 

Aaron

Lieutenant
Nov 3, 2016
533
Colorado
Why do you think piston 6 melted? you claim temps were fine, but maybe you didn't check? how long were you beating on it prior to this happening?
I didn't 'claim' temps were fine, I said they were fine. Not I think they were, or I hope they were, but they were.

Oil, water, and intake temperatures are only loosely related to actual cylinder temperatures. That's why so many serious builds document and rely heavily on EGT readings, because those are very telling of actual cylinder temps. And with our notoriously restrictive turbine housings and exhaust manifolds, the problem is compounded.

I'm open to ideas though, what else could it be? A valve seal failure, but our weak pistons are much more common failure points than the valves.


Made decent progress today. Bumper, radiator, intake manifold, and coolant overflow are all off. Next step is the starter, remaining bell housing bolts (3 or 4), wiring, and it's ready. As of yet I don't see any problems on the front of the engine.

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Aaron

Lieutenant
Nov 3, 2016
533
Colorado
That wasn't exactly how it went! It was more like "Here's your street tune, but that's too aggressive for extended track use so use this dialed back track tune instead." Then I said "Fuck that little bitch" and ran the street tune anyways.

Haha! Although I'm not sure why you like me (I mean I am hung like a horse but that's weird), I like ya too. Simply because you understand the physics behind what is happening.
 

Rob09msport

Captain
Oct 28, 2017
1,164
Monroe CT
Deff have to say I think most tuners would have no clue to be able to do that and if they made a tune with good logs that wasn't glory run would prob say it's safe on track you deff sold me on v8bait for my tune
 

Aaron

Lieutenant
Nov 3, 2016
533
Colorado
There's none better, that's for sure.

Got everything pretty much ready, just got a couple more wires and hoses and it'll come out. I'm trying not to make this thread a how to pull an engine for retards, but do yourself a favor. Grab a set of standard flex-head ratcheting wrenches. The E-torx bolts on the bell housing can be difficult to get to. Standard 12 point sockets/wrenches grip them perfectly. 7/16" for the top 2 steel bolts, 9/16" for the 5 large aluminum ones. You're welcome.

Also, I did a thing. #becauseracecar. So much for that stock rebuild.

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Aaron

Lieutenant
Nov 3, 2016
533
Colorado
Good, I was going to wait but given $100 off I just couldn't. I currently run the Ambient Thermal Management intercooler, which seems to have served well. I know they test well. IAT's don't have a huge amount of impact on overall cylinder temps, but they do have an impact of course.

My main reason for swapping turbos is to get better manifolds and a larger turbine. I feel like that change would be huge for lowering cylinder temperatures. For this reason the MMP's and GC's stand out, but I have hesitations for both. MMP's are hugely oversized for my goals, and GC's have some reliability and warranty questions linger.

I've been following your build since day 1. I love the quality and attention to detail of your work. I will continue to talk trash about your womanly legs being unable to operate a man's transmission!
 

Aaron

Lieutenant
Nov 3, 2016
533
Colorado
Motor is ready, there's absolutely nothing still connected or interfering. I actually prefer to pull the N55, with the DME on the intake it makes clearing out wires a lot easier. But since I'll be pulling the head off I decided to go ahead and remove all the wires now. I dread the day when I have to figure out their routing, tie points, and attachment points. I'm OCD about that, so I won't quit until it's OEM perfect, meaning I'll spend weeks routing fucking wires.
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Aaron

Lieutenant
Nov 3, 2016
533
Colorado
No external signs of a failure, all charge piping is in tact, turbos look good. I do have signs of a VCG leak, I've replaced that fucking twice now. I'll be able to do a better job this time with the engine out.

Tear down is scheduled for this weekend. Are there any special tools required to take the head off? I know I need the timing tools eventually, but I don't need them to tear it down right?

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dyezak

Major
May 4, 2017
1,768
Plano TX
There's a set of swingarm/fork lifts in the garage but no motorcycle in sight. That's taking the squid scene to a whole new level.
 
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