[saxman42]

Hey Everyone,

I've been reading all of the pages of posts related to the timing chain problem with the N20 engine. Some of the "facts" are inconsistent and I'm hoping someone can clear this up:

1) Most people are saying the new chain only comes in cars built after 1/2015 since the part number changed on that date. It seems like the main reason people go off of this is because one guy wrote one article (see below) about how BMW changed a part number on that date.
http://www.rightfootdown.com/cars/au...nents-n26-too/

Other people have said their SA went to BMW training on this issue and that the new part has been used under the old part number for at least a year before the part number was changed. This seems to line up better with the BMW TSB which says it only applies to cars built before 3/2013.

2) The author of that article mentions the date of 1/2015 because RealOEM says that's the date the part number changed. Is RealOEM referring to build date, or model year?

3) Even if the new chain wasn't used until the part number was released in 2015, is there any proof that they scrapped all of the old chains and started using the new one on that date? It's not uncommon for a factory to use up old supplies

It seems like there are a lot of assumptions being made about this problem and very few of them have been backed up with official information from BMW or people directly involved with fixing the problem. Can anyone confirm, with a reliable source, a specific build date or model year that the timing chain fix was implemented?

Thanks in advance for the help.

[D041987]

Real OEM part numbers usually are correct and give the full on in date use of the part for a car. So chances are that if a car was a month back it is a 50/50 shot if the parts are of the new revised edition or the older stock. That being said Not every car is affected but there were issues found on cars that had long service intervals. Like the BMW 12K miles oil change (Total BS, change your oil every 5K) But better safe than sorry as it is a expensive repair but I think BMW has a extended service interval on this issues.

The numbers they mention are of the production of car for that start date. So 1/2015 means any cars built during that month and onward have the latest revised part.

You will never get the correct answer to this question but easiest thing to check would be to look inside your oil cap. If you have a really dark brown/ caramel chain guide than you have the older chain. If it is a coffee color chain guard than it is the new chain as the new plastic pieces that came in the kit are white and will get a little darker with oil and time. And BMW only replaced the entire assembly not just the chain itself as it was both the chain and the guides that had issues.

OLD Chain Guide:


New Chain Guide:

[saxman42]

Thanks. I don't own one yet, but I've been seriously considering one of two CPO 328is. I'll definitely be checking under the filler cap before committing to anything. I've read a few posts indicating all of the chain guides start white and darken over time. Are you sure the guide in that first picture isn't just darker because it's older? In this BMW N20 production video from 2012, the chain guides that are installed are white (go to 1:30 into the video).

I also noticed on RealOEM that the chain tensioner part number never changed; only the timing chain part number.

[MONSTAR]

I love it. Please come be a part of our community. 3 posts and already getting down to business!

[saxman42]

Originally Posted by MONSTAR

I love it. Please come be a part of our community. 3 posts and already getting down to business!

Haha. Thanks. I'm an electrical engineer and deal with running design changes like this all the time. I just want to get the facts straight so myself and others can be familiar enough with the problem to decide which cars are at risk and if that risk is worth the reward. I know it's easy for things to get confused when everyone's hysterical about possibly having to pay $20k for a new engine in their very young car.

[MONSTAR]

Maybe I missed it, but did that guy even set the time on the chain?? I'm used to seeing 3 silver colored links, 1 that lines up with a dimple on each cam sprocket and 1 for the crank? Also, how did he even slip the bottom of the chain around the crank like that?

[saxman42]

Originally Posted by MONSTAR

Maybe I missed it, but did that guy even set the time on the chain?? I'm used to seeing 3 silver colored links, 1 that lines up with a dimple on each cam sprocket and 1 for the crank? Also, how did he even slip the bottom of the chain around the crank like that?

I think the timing is set with the jig he was building it in. It looks like that metal tool is keyed to line up the timing. It also looks like the crank gear is already in that assembly, too.

[slugmaster]

I just checked the chain guide on my MY 2014 build 6/2014 328 and it looks like I have the new design. It is light orange instead of dark brown. This supports that the new part was used before 1/2015.

Great thread

[Billfitz]

As noted already it's quite possible that the color has less to do with whether it's the new or old design as it does the mileage on the engine, as it may very well continue to darken with age.
There is a visible difference between the old and new oil pump chains, see in this picture:


The links of the old version are all made with two plates back to back. In the new version the center links are still two piece, but the inboard and outboard links are one piece. There must be pics of the old versus new timing chains as well.

[slugmaster]

Originally Posted by Billfitz

As noted already it's quite possible that the color has less to do with whether it's the new or old design as it does the mileage on the engine, as it may very well continue to darken with age.
There is a visible difference between the old and new oil pump chains, see in this picture:


...

Is the chain in this picture the same chain as in the second post? I might be missing something but the chain in the second post does not have the middle links.

[saxman42]

Originally Posted by slugmaster

Is the chain in this picture the same chain as in the second post? I might be missing something but the chain in the second post does not have the middle links.

The chain in that post is the oil pump chain. The chain on the second post is the timing chain. They both got new part numbers. Does anyone have a picture of what the new timing chain looks like? What changed?

[Billfitz]

I haven't seen one. The oil chain picture was originally posted in a timing chain thread, because when the one goes the other tends to as well. A broken timing chain in and of itself probably won't be catastrophic, but when pieces of a broken timing chain cause the oil pump chain to fail it's usually game over.

[E81]

Does anyone know the actual or even estimated failure rate of the old design? The internet is relatively quiet about the issue compared to number of engines produced. Nothing compared to N47 timing chain issues. My bet is the failure rate is actually quite low.

Another question is why is this only N20 issue when the timing chain and some of the chain guides are same in N52 and N55 engines? I never heard of timing chain issues in those engines.

[Billfitz]

I'd say that N52 and N55s don't get pushed as hard as N20s, not only from having more torque available, but also because of the different demographics of their owners. Cars with sixes cost more than cars with fours, so the driver is likely to be older, with more conservative driving habits.

[saxman42]

I've been thinking about this a lot and I honestly don't see why changing the timing chain fixes anything. Isn't it the timing chain guide that breaks? That part number hasn't changed. I wonder if BMW switched vendors for the timing chain guide around 2013 due to the previous vendor not making them to the proper spec. It's very common for companies to switch vendors because of quality problems but not change the part number since the specs didn't change.

Also, I talked to a SA at my local dealership. For what it's worth, he said he's only personally seen one 328i engine replacement since he started working there 17 years ago.

[Billfitz]

That's the $64,000 question: which breaks first, the chain or the guide? Then there's the matter of the chain tensioner, which is also suspect and has been superseded. It's been suggested that a new tensioner may prevent the chain from either jumping the sprocket or breaking the guide due to the chain stretching over time. All I can say for sure is that when the dreaded whine occurs foreshadowing impending doom they replace all three.

[slugmaster]

Originally Posted by E81

Does anyone know the actual or even estimated failure rate of the old design? The internet is relatively quiet about the issue compared to number of engines produced. Nothing compared to N47 timing chain issues. My bet is the failure rate is actually quite low.

Another question is why is this only N20 issue when the timing chain and some of the chain guides are same in N52 and N55 engines? I never heard of timing chain issues in those engines.

The failure rate seems low. The reliability history published by Consumer Reports from earlier this year, shows Engine Major and Engine Minor are not trouble spots for any years 2012 - 2016. 2012 does have a slightly lower ranking than 2013 and later in engine minor. The overall reliability for 2012/2013 is below average. 2014 - 2016 are average or higher

[Delija]

Maybe we could create a poll here - to see how many N20 owners we have here and how many of them have this problem.

[madmortar]

Originally Posted by Billfitz

I'd say that N52 and N55s don't get pushed as hard as N20s, not only from having more torque available, but also because of the different demographics of their owners. Cars with sixes cost more than cars with fours, so the driver is likely to be older, with more conservative driving habits.

I dunno, that seems like a huge stretch of a statement.
N20 is in X3, 228, 328, 528, etc etc. Tons of models that are not bought or driven for performance. And there have been issues of the timing chain in X3's driven by soccer moms so..

Also, look at the aftermarket for N52/55...it's huge. I think based on the marketing push and sales of aftermarket parts for the inline 6 vs 4, my opinion would be that people track/drag/push those cars just as, if not harder than ones with N20.

[atam1980]

Originally Posted by Delija

Maybe we could create a poll here - to see how many N20 owners we have here and how many of them have this problem.

you'd be taking a really small sample of the population, and most, if not all, of the people that have had the problem have moved on and are no longer active on the forum.

[CalCarNut]

Originally Posted by Billfitz

I'd say that N52 and N55s don't get pushed as hard as N20s, not only from having more torque available, but also because of the different demographics of their owners. Cars with sixes cost more than cars with fours, so the driver is likely to be older, with more conservative driving habits.

Huh?

I have one of each...(N52 and an N26). I've stomped the crud out of the N52 to see what it'll do. It's in an X3 and quicker than I expected. I don't make it a habit but same owner/demos . I also am easy on my N26. I've only turned off the DSC system once, never have used the launch control function, and am generally pretty easy on the car.......other than going to 'sport' mode and using the paddle shifters when I want to......

[Billfitz]

Look at the mod threads. You can pretty much tell that the guys doing mods tend to be younger, they're not doing mods because they're conservative drivers, and it's mostly 320 and 328s that they're modding. I took a glance in the F10 forum, the same applies to the 528 versus 535, and there are timing chain threads about the 528, but not the 535.