[gwest]

For my 2022 Covid retirement project I bought a moribund 2013 BMW 118i sight unseen. The owner said that the car went into limp mode and after that wouldn't start. But he wasn't going to go into details. After a bit of reading up I got the impression that the problem could well be electronic, and might give me the opportunity to don my dust coat, and get some use out of my stethoscope, newly acquired endoscope and diagnostic tool. A proper white gloves job.

It was therefore with some disappointment that I observed coolant running out of the exhaust pipe when the vehicle was delivered! And when I drained 7 litres of emulsified oil from the sump! This turned into a rubber gloves and gumboots job! The cylinder head was warped 0.012"and its hardness was down to 73 Brinell. Unusable. The engine had obviously been over-heated. Coolant had leaked into the electrical contacts in the coolant level alarm at the base of the expansion tank so it would have been disabled. And the O-ring in the temperature sensor at the rear of the engine was degraded. A classic case of neglect. It also cast doubt on the condition of the block, and it would take a full strip down to evaluate this.

I bought a used N13B16A engine from a wrecker who claimed it was low mileage. I knew that I needed to transfer the turbo charger assembly to it as it came without an exhaust manifold. But I then noticed that the replacement engine had no oil cooler on the oil filter housing, and no oil level sensor in the sump. Its engine number was A276J068 whereas mine was A993J465, so mine was quite a lot later in the sequence. I am now thinking that it came from a 116i, as I understand that these do not have the oil cooler. I can transfer the original oil filter housing and sump to the replacement engine, but am wondering if there are any other complications in store that I an unaware of?

 

[martin10chk]

I am not an authority on this but did look into it a bit in respect of my 316i ... just out of curiosity and because I have mapped it to 180bhp.

So the oil cooler is just about the only parts difference and should swap over fine. The differences between the lower end (18i and 16i) variants of N13 variants is otherwise down to ECU mapping. Whilst the oil cooler is always good, it is hardly necessary in the UK climate at least. I have monitored mine (once remapped) and never had oil above 120 yet.

Hope that helps. I am sure there are others on here who know more.

 

[gwest]

That is reassuring Martin. I am going to replace all the 'rubber' seals and O-rings anyway so I will transfer the 18i oil filter housing to the replacement engine. I will also have to transfer over the oil pump solenoid and harness - my original one is in better shape than the 16i and the rubber seal through the side of the block is not leaking, unlike the replacement.

 

[gwest]

I did discover that I needed to transfer over from my 18i the sump with oil level sensor as the 16i did not have this. Which also meant changing the splash guard but that was painless. However, the replacement engine looked pretty coked up so I decided to remove the head to clean the pistons and valves. Fortunately the head was straight and hard (>100 Brinell) but it showed signs of battering possibly from a broken spark plug, and scratches indicated that the head had been off before. And it was unlikely to have been a low mileage car. Thinking that high mileage might show up in the pistons and rings I removed no.1 piston to check the ring gap and found that the 2 compression rings were near the upper limit (0.8mm (1) and 0.75 (2) vs 0.95 and 1.06mm respectively (data from BMW). I don't normally bother to check the oil rings as the three-piece scraper rings are so flimsy but this engine had a two-piece oil ring with a coil spring sitting in its groove, so it was easy to check. This was where things became a bit weird- there was no gap when I placed it in the bore. In fact it was distorted indicating that it was bigger than the bore. I am assuming that the rings are original and will check the new ones when I get around to buying them.

 

[gwest]

I should have added that the ring gap for groove 3 is 0.10-0.40mm, with a wear limit of 0.82mm (BMW)

 

[gwest]

I finally got a photo of the oil ring- see below. My current thinking is that the gap between the segments allows the oil ring to be compressed into its groove and hence provide the force to keep it against the bore. The coil spring just seems to keep it tidy? I have not found any online information on this type of oil ring.

 

[gwest]

The replacement oil rings were of the conventional 3-piece design and fitted predictably. Time will tell how the oil consumption fares. I have now progressed to the stage where I am fitting ancillaries like the vacuum pump. I thought I would check it for wear and replace the three O-rings but what I found has me puzzled. Apart from the expected signs of minor wear on the base and on the inner face of the oval cover, there was a narrow wear mark on one side of the cover in a position that corresponded to the short axis of the oval top hat. I then checked a similar unit from a Peugeot 207 that had covered 100k km and it was very similar.
The wear marks are about 5-6mm wide. The slippers that rub against the sides of the cover are 16mm wide. How is it possible for this wear pattern to eventuate? I have read about vacuum pump noise in Minis being checked by disconnecting the vacuum hose and if the noise disappears then the unit is considered ok. I must put a stethoscope on my Citroen DS5 THP155 that has covered 87k km and see what I can hear. On this rebuild because of the inaccessible nature of the unit on the 118i I will buy a new one.

 

[tweeky]

Did you get the Ecu ? other wise this all could be in vain and need to do a bit of coding once the engines in.

 

[gwest]

Tweeky, I am hoping that when the patient eventually comes out of its coma, that apart from some bad behaviour on its first outings, it will eventually work out by itself some sensible settings to run with. That way it need never know that it has had a transplant from a very dubious source. This approach did eventually work with a Peugeot 207 Vti that previously had the same operation. But I will update should I ever get the BMW to fire up - at the moment I am a little daunted by the pile of engine wiring harness that needs to find a home.