Bimmerfest - BMW Forums - View Single Post - signs of F30 N20/N26 timing chain issue, and OCI to the rescue?
View Single Post
  #90  
Old 05-04-2017, 11:25 AM
imtjm imtjm is offline
Officially Welcomed to the 'Fest
Location: VA
 
Join Date: Oct 2004
Posts: 1,992
Mein Auto: 328ix sdn; M240ix cpe
Quote:
Originally Posted by namelessman View Post
The slide rail and guide rail are the same part#, the changing from white to dark brown color is likely due to exposure to high shear/high temp for 10k's of miles.

There is no comparison of brand new part# before and after 1/2015 on the timing chain itself. Looking at my MY13 with 45k versus relatively new 2017 with, say, 4k miles, the timing chains itself look structurally the same, while the old one with 45k is slightly bronze-color(due to 10k's of high shear/high temp?!?) while the new one with 4k looks chrome.

BTW, the oil pump chain also has new part#, those part# do have structural differences, e.g. online pictures show that the center links of old part# are made of 2 plates, while the new part# are made of one solid piece.

It is worth noting that bmwtechnician.com does show how the rails broke, so there is factual evidence of failures. From the pictures/videos, the failure point is the snap attachment of the slide rail(#1 in diagram) and the guide rail(#2). The guide rail piece with the holes broke off, and that's not normal.

But given that Munich engineers were OK with that snap attachment in the first place, it would seem the expectation is there should be zero/minimal stress and force on the rails, hence those flimsy looking attachment points are not expected to be weak links.
well, it's interesting you mentioned bmwtech, because he posted that the plastic was different. I suppose, I should not be using one statement of his over another without any evidence of anything, either, so shame on me for that.

He shows rails broken, yes, so what? The complaint is about the TC. Yes, yes, people are guessing and sleuthing that slack in TC is braking the plastic components, but no one, even bmwtech, didn't actually show or measure the length of the old TC to new TC. Measuring the stretched length would indicate if the TC was in fact stretched; however, even then, bmwtech also did not show any evidence that x length of slack causes broken plastic rails. Plus, we don't know how the vehicle with the broken rails was used or maintained. Maybe he just got a bad part or production lot. Again, lots of sleuthing without any factual information. What factual evidence showed it was a bad TC over a bad guides and rails? As I noted, I never disputed that there were reports about busted guides and rails. I disputed the notion that it is widespread and disputed the TC is a widespread issue. You'll notice the new TC also supercedes TC from 2004-2011, so did we see failures in TC's replaced in 2004-2011 models? No. anyhoo, again, using anecdotal stories without actually showing facts about cause-effect or even showing comparisons is not a widespread epidemic make.

As fas as the oil pump chain: it wasn't an issue was it? It wasn't, yet the part number changed two times. Actually, I haven't seen any differences in the oil pump chains. I'd like to see what you saw online. One needs to ensure they are looking at an actual BMW part rather than febi, IWIS, etc. but I don't understand what you mean by two plates versus one. anyhoo, the oil pump chain hasn't been a complaint, though.

Last edited by imtjm; 05-04-2017 at 11:26 AM.
Reply With Quote