N63B44B rebuild

[Chrisg2121]

Hello so this is my first post I just wanted to do a build thread. This 2012 750 is a puzzle of a car it’s been sitting torn apart for over a year n I am receiving it in pieces. The engine was taken out as well as the transmission, radiator, n condenser (all were removed separately for some reason I watched this all happen). The engine has the heads n all accessories removed. To make a long story short a customer from the dealer next door bought this car n blew it up within a month. It had some sort of warranty which is why the engine was torn down by the last technician (they needed pictures of the damage) anyways the warranty was ultimately denied n the vehicle was taken back as a trade in. One of their employees bought it for fairly cheap n came to me to see if I would be willing to rebuild it n put it all back together (he’s too cheap to buy a used engine for 10k)
So piston # 4 melted and left a slight gouge on the cylinder wall (pistons are proving to be hard to find anywhere else but the dealer unless we get a used set) This vehicle only has 50,000 miles so I’m not sure exactly what the customer did to blow it up but it definitely looks like some detonation damage everything else looks great, that gouge on the cylinder wall somewhat worries me (but I’ve seen worse that have ran) so we’ll see what the machine shop says. This vehicle did come in running completely fine other than the misfire on cyl 4.
As of now I’ve torn the block apart completely n I am getting ready to send it to get honed? (not sure that’s what it’s called for alusil cylinders) I am getting the cylinder heads resurfaced but I need to still disassemble all the valvetronic stuff so I can send them out, once I get them back I will be replacing the valve seals. So far I think I will only be replacing the pistons, rings, and gaskets I will be updating everything as I go

[Chrisg2121]

So I got the crank removed n was able to get the heads torn apart today to get them ready to send out to the machine shop. Found some used pistons for the n63b44b but they want over 200 for one used one n new ones are a bit more we still need rings so I would still have to source that (I can only find those through the dealer for the n63b44b). I found a set of pistons n rods out of an n63b44a (rods are totally different) n I can find aftermarket rings for those way cheaper they look identical, diameter is the same, wrist pin diameter is the same, n so is the compression height on both so we’re going to purchase those n hopefully they match up if they do we’ll go ahead n purchase the rings for those pistons.

[Chrisg2121]

Everything is back from the machine shop n looks great I was able to get the crank dropped in n that’s about it for now. Pistons and rings have been ordered just waiting on those they should come in Wednesday

[Chrisg2121]

Definitely the most beautiful engine block I’ve ever seen
It’s also ridiculously light there is no weight to it when empty

[Kyngofpop]

This is probably the first time I've heard a vehicle owner being blamed for "blowing up" an N63. As a 550xi owner that's TERRIFIED to drive my car for fear of the motor going, I can say that it probably wasn't the owners "fault".

There's heaps upon heaps of stories of N63's just randomly and mine too is problematic...

[Chrisg2121]

Originally Posted by Kyngofpop

This is probably the first time I've heard a vehicle owner being blamed for "blowing up" an N63. As a 550xi owner that's TERRIFIED to drive my car for fear of the motor going, I can say that it probably wasn't the owners "fault".

There's heaps upon heaps of stories of N63's just randomly and mine too is problematic...

Not directly blaming the customer the dealer could be at fault as well since it’s possible the vehicle could’ve had some issues that weren’t addressed when it left but that should’ve been noticed when purchased
No matter what though this kind of catastrophic damage could’ve been avoided had the customer brought it in for repairs I understand its a new vehicle to them n things should’ve been done before the vehicle was sold but ignition coils or any sensor can randomly fail so there must have been some major warning lights or some sort of hesitation, oil burning, misfires or something to let the customer know that he should probably bring it in but it was ultimately ignored n this happened thanks to the ignorance of the customer
No engine just randomly blows up that is misconception people put into their minds to blame the manufacturer or some shenanigans
It all comes down to proper maintenance and preventative repairs as outlined by the manufacturer or recommended by a trusted shop but most people ignore these things or claim they’re being ripped off
Their warranty wasn’t denied because they were blamed for the damage it was denied because they never transferred the policy into their names
But like I said this kind of damage can always be avoided engines don’t just blow up

[Chrisg2121]

So pistons n rings arrived last week only differences I see is ring thickness and dome shape is slightly different the replacements came with rods attached so I got those swapped n the rings installed other than that the only other progress I have made on this is getting the valve stem seals replaced on one cylinder head both intake n exhaust valve stem seals were leaking pretty bad bmw is notorious for this on their engines but I didn’t think it would be this bad at just under 60k miles hopefully I can finish the other one a bit sooner then get the pistons dropped in to get it all assembled soon

[Chrisg2121]

Valve stem seals all done on one head both intake n exhaust valves n seats cleaned up great both camshafts n eccentric shaft installed

[Chrisg2121]

Here’s some close ups of the valvetronic rockers n springs

[Chrisg2121]

So I’ve gotten a few things done since my last post. I got the pistons all dropped in and the heads installed.

[Chrisg2121]

I finally got the car pushed over into my shop along with all the parts for it as well, now this will take me some time since I’ve never had one of these apart before n I didn’t disassemble this in the first place but I’ll try my best. I also washed off the oil pans, valve covers, n timing cover.

[Chrisg2121]

I got the oil pump installed along with the outlet tube, return tube, n oil pump drive chain.

[Chrisg2121]

I got the timing chains installed as well as the timing cover, water pump, n harmonic balancer. The balancer mark (MP) needs to face the divet on the timing cover after that it is ready for the cams to be set

[Chrisg2121]

After lining up the MP mark on the balancer to the timing cover you then line up the flat spots facing up on each camshaft then timing is all set. (Didn’t have the right timing tool so I had to improvise) I double checked to make sure timing was right by spinning it over n making sure my firing order was right. Sure enough it was all good n everything lined back up great after. I got most of this done today since I couldn’t do much actual work due to the heavy rain here

[Chrisg2121]

I got the upper n lower oil pan installed

[Chrisg2121]

I got the exhaust manifolds on as well as the turbos n some plumbing for the vacuum pump. The alternator n the catalytic converters are on as well but I’m still figuring out where all the brackets n heat shields go so I may have to disassemble some of this if I realize I forgot something

[Chrisg2121]

I started plumbing the turbos n called it quits for the day. I’ve got a lot installed already yet there’s still tons of parts left to put on

[Chrisg2121]

I got the valve covers installed n replaced all the o rings for the crankcase ventilation system. I also got the wiring harness on as well as the fuel injectors n high pressure fuel pumps

[Chrisg2121]

I got the intake manifolds, intercoolers n some heat shields put on as well as the ignition coils n the belts

[Chrisg2121]

Finally coming off the stand almost ready to be back in the car. They’ve been separated for so long. I got the rear water jacket cover installed as well as the flex plate (forgot to take a picture)
I also dropped the front subframe to install the engine n trans

[Chrisg2121]

Engine n transmission bolted together n dropped on the subframe
Dropping the vehicle onto frame

[Kyngofpop]

Big props to ya man cause you sure are doing the thing. Awesome project and much success. Love following threads where there's work being done and we can certainly it. These motors aren't the garbage ppl make them out to be, just need dedicated mechanics willing to go the extra mile.