[MatF30UK]

IWIS N47 chain kit, oil, coolant, rocker gasket, injector seals and whilst the engine was out I also had a new LUK dual mass flywheel and clutch installed along with a new starter. Total cost for all work £2980.

I need to say a massive thanks to ADC, absolutely amazing work.

Anyone who thinks the N47 snapping chain thing is exaggerated should see the yard full of F30's they have queued up down there waiting to get on the lift.











[/CENTER]

[Watsey]

It’s a real shame that it happened, but seems like a quality repair.

[TurboWeasel]

Blimey, it took the cam bridge out! Not good. Kudos for repairing it. Most people would scrap it.

I wonder if ISTA can show cam to crank correlation angles? Monitoring that would give you advance warning of the chain getting too slack, either through worn out links or a guide snapping/falling off.

Nice drive right there. E30 and R32 I had to do the chains on both of my R32s, so it's not just a BMW thing

N57s don't seem to be as hungry for chains as the N47 thankfully. I think because it's a more balanced engine, so no snatching on the chain between firing cycles.

[Watsey]

Originally Posted by TurboWeasel

Blimey, it took the cam bridge out! Not good. Kudos for repairing it. Most people would scrap it.

I wonder if ISTA can show cam to crank correlation angles? Monitoring that would give you advance warning of the chain getting too slack, either through worn out links or a guide snapping/falling off.

Nice drive right there. E30 and R32 I had to do the chains on both of my R32s, so it's not just a BMW thing

N57s don't seem to be as hungry for chains as the N47 thankfully. I think because it's a more balanced engine, so no snatching on the chain between firing cycles.

Plus, doesn’t the N57 have double row chains ?

[TurboWeasel]

Originally Posted by Watsey

Plus, doesn’t the N57 have double row chains ?

Unfortunately not. It's the same simplex chain as the N47. Duplex chains were dumped years ago.

It is at least a roller chain which gives a fighting chance for lifespan. The newer link style of chain is notorious for failing in diesel engines due to soot abrasion.

Another thing on the N47/57's side is rear mounted chain gear. When it was front mounted on the M57, that tended to put too much load on the front main bearing as there was also A/C and alternator load to deal with. So BMW moved it to the back of the engine. Their reasoning was reduced load and the rotating mass of the torque converter/flywheel absorbing some of the vibration.

As to why N47s lunch their chains more often than N57s I think is partly down to neglect. No offence intended but the 20d was more of an economy car and was therefore treated as such by a lot of previous owners. It's more or less universally accepted that frequent oil changes is the key to lifespan, otherwise oil clogged with too much soot acts like a mild grinding paste.

[TurboWeasel]

A further thought.....could start/stop be a contributing factor, especially in heavy traffic? Every time a cylinder catches during fire up, it must jerk on the chain, especially on high compression diesels?

It's one of the reasons why I disabled SS.

[Watsey]

Originally Posted by TurboWeasel

A further thought.....could start/stop be a contributing factor, especially in heavy traffic? Every time a cylinder catches during fire up, it must jerk on the chain, especially on high compression diesels?

It's one of the reasons why I disabled SS.

Yes that’s also my reasoning for coding Stop Start off as default. I never ever use it because of the inevitable chain lash.

[MatF30UK]

Originally Posted by TurboWeasel

Blimey, it took the cam bridge out! Not good. Kudos for repairing it. Most people would scrap it.

I wonder if ISTA can show cam to crank correlation angles? Monitoring that would give you advance warning of the chain getting too slack, either through worn out links or a guide snapping/falling off.

Nice drive right there. E30 and R32 I had to do the chains on both of my R32s, so it's not just a BMW thing

N57s don't seem to be as hungry for chains as the N47 thankfully. I think because it's a more balanced engine, so no snatching on the chain between firing cycles.

Thanks mate, I'm planning on doing the chains on the R32 myself, maybe over christmas but it looks like a bit of a monster job, I have been getting quotes of £2500 to do it by Indies but having looked whats involved that actually sounds about right now lol... I'm keeping it forever so may as well get it done.

Great all this new technology My E30 took about 90 minutes when I did the cam belt lol!

I coded stop start out when I got the car four years ago, not because of the chain, just because I hate it lol... Its had 10k miles services from new though with full history stamped up so very frustrating it went bang with so few miles on it :-(

[barf]

It's not possible to measure the chain with ISTA. With N47 and N57 the chain needs to be replaced every 200-250k depending on how much you drive. Regular oil changes are a must. Snapping chain on N47 usually does not damage the head and you only need to replace the chain.
The chain is the least of the worries with this engine. Be more afraid of main bearings on N57. For N47 its usually not a problem unless you have really not changed your oil

[Watsey]

Originally Posted by barf

It's not possible to measure the chain with ISTA. With N47 and N57 the chain needs to be replaced every 200-250k depending on how much you drive.

Presumably you're talking kilometres ?

[barf]

Yes. With unknown history or prolonged oil service interval i would replace the main bearings & conrod bearings on N57 aswell at 200-250k km, especially if you are running any serious power on it. N47 its not that much of an issue but have seen many failures for that as well. Mostly on E9x though.
B47 is solid, not many problems with chain or bearings.
Over here its quite normal to do this kind of service.
UK police has seen the consequences of N57 bearing failure and its not isolated to their driving style.

[TurboWeasel]

Originally Posted by MatF30UK

Thanks mate, I'm planning on doing the chains on the R32 myself, maybe over christmas but it looks like a bit of a monster job, I have been getting quotes of £2500 to do it by Indies but having looked whats involved that actually sounds about right now lol... I'm keeping it forever so may as well get it done.

Great all this new technology My E30 took about 90 minutes when I did the cam belt lol!

I coded stop start out when I got the car four years ago, not because of the chain, just because I hate it lol... Its had 10k miles services from new though with full history stamped up so very frustrating it went bang with so few miles on it :-(

It's not too bad a job once the gearbox is dropped, so probably a good time to change clutch as well if it's a manual.

If you have VCDS, have a look at measuring blocks 208 and 209. You want to see 0 to -3KW in there and all is good. -8KW is the outer limit and time to do the chains. If they get to -10KW, you'll get a EML on the dash as the engine ECU can't 'see' the cams anymore.

I know of only 1 car where the chain actually snapped, so it's super rare! The MK4 was far worse for chain wear. MK5s are OK but still need doing eventually.

I cost me £1400 to get the chains done, but that was a good 10 years ago now. £2500 is insanity! I hope that includes genuine parts and not Chineseium ones!

Lol, E30s are magic to work on.....but they throw you off a wet road far easier than an F30

Yeah I hate SS. Just utterly pointless for 1 or 2 mpg and hard on the starter, battery and engine.

[TurboWeasel]

Originally Posted by barf

Yes. With unknown history or prolonged oil service interval i would replace the main bearings & conrod bearings on N57 aswell at 200-250k km, especially if you are running any serious power on it. N47 its not that much of an issue but have seen many failures for that as well. Mostly on E9x though.
B47 is solid, not many problems with chain or bearings.
Over here its quite normal to do this kind of service.
UK police has seen the consequences of N57 bearing failure and its not isolated to their driving style.

Well maintained stock N57s rarely suffer main bearing failure. If it does suffer from that, it's usually always the front bearing caused by crank pulley wobble from a failed vibration dampener.

If main bearing 4 goes (which the N55 suffered from mainly) that's usually oil way plugging from neglect, or oil surge from cornering too hard with low oil in the sump. N47/57 doesn't have a baffled sump.

UK police situation was found to be oil degradation from long service intervals, extended periods of idling followed by sudden full throttle acceleration. 8 N57s were sent to a test facility in Austria and the suggest fix was more frequent oil changes (surprise surprise) and switching to 5W40. Average consumers are unlikely to ever experience that problem. Untimely valve cover gasket replacements also caused thinned out, roasting hot oil to drip onto the manifold, which is likely the cause of the engine fire that sadly took the life of a police officer.

Tuning only clobbers the rod bearings if boost onset is too early, which can also crack the pistons. Need to watch out with that and tuning as the upper bearings are sputter, so harder than the crank. Damage those and it's new crank time. It's why BMW's tuning is linear. Component protection.

[closetwagonlover]

OP, do you use the stop/start in traffic feature? Just curious.

[barf]

Originally Posted by TurboWeasel

Well maintained stock N57s rarely suffer main bearing failure. If it does suffer from that, it's usually always the front bearing caused by crank pulley wobble from a failed vibration dampener.

If main bearing 4 goes (which the N55 suffered from mainly) that's usually oil way plugging from neglect, or oil surge from cornering too hard with low oil in the sump. N47/57 doesn't have a baffled sump.

UK police situation was found to be oil degradation from long service intervals, extended periods of idling followed by sudden full throttle acceleration. 8 N57s were sent to a test facility in Austria and the suggest fix was more frequent oil changes (surprise surprise) and switching to 5W40. Average consumers are unlikely to ever experience that problem. Untimely valve cover gasket replacements also caused thinned out, roasting hot oil to drip onto the manifold, which is likely the cause of the engine fire that sadly took the life of a police officer.

Tuning only clobbers the rod bearings if boost onset is too early, which can also crack the pistons. Need to watch out with that and tuning as the upper bearings are sputter, so harder than the crank. Damage those and it's new crank time. It's why BMW's tuning is linear. Component protection.

The main problem of oil degradation comes from the issue of DPF along with long service interval. Of course driving style of the police was increasing the problem but was not the underlying cause of cheaping out on materials.
I have heard the theory of vibration dampners being the issue but to me that is a fairy tale because of M57. How often do you see bad bearings on those? Its relatively rare although there are a lot of shot vibration dampers on those aswell and over here almost are all neglected and running some sketchy stage1s and dpf deletes.

I don't believe untimely valve cover gasket replacement theory but the valve covers themselves are an issue on the N series diesel engines. They start to leak from the seams if i call it correctly leading to many people replacing the seals thinking thats the issue but its usually the cover itself. Thats why there is aftermarket covers sold for them aswell.

Just this summer i saw an X5 with under 100k miles driven and suffered main bearings problem. Properly serviced at the dealer and later by independent with more regular intervals.

We can all make justifications to defend something that is badly engineered reliability wise but it is what it is. Starting from the chain problems on N47, EGR problems requiring a recall, lots of bearing failures, HPFP issues. While M47/M57 is still going great even when neglected and there isn't many problems with the B47/57 that i've heard from the dealers mechanics.

And also its not related but its not the boost that is the issue but too early SOI when you tune the diesels but you have to be really confident tuner to go too early on SOI anyways.