BMW 1 Series 118d - BMW N47 Timing Chain

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Sun 21 Oct 2012 15:24
BMW 1 Series 118d - BMW N47 Timing Chain - Grease_monkey

I am looking/was looking at purchasing a BMW 1 Series 118d. The car was registered October 2009. I'm very concerned to be reading about timing chain failures on this engine. I believe the crank was changed from 01/09 so the car i'm looking at should have this new crank fitted from the factory. Thing is i'm reading about people who have had problems with cars from 07 & 08 but not seen any problems reported for cars from 09. Even in the honest John review section for what's bad it's 2, 07 cars and a 08 with timing chain problems.

Did the new crank sort most of the timing chain problems?

MTIA

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Sun 21 Oct 2012 19:06
BMW 1 Series 118d - BMW N47 Timing Chain - 659FBE

I'm not familiar with this particular diesel engine, but I've tested enough of them in my time to make some observations which I have found to be generally valid:

The only long-lived chain configuration I have found to be suitable for a diesel engine is a duplex roller chain, preferably with a hydraulically damped rolling sprocket sprung tensioner. A single chain or a hy-vo type chain will not last much longer than a good belt and is far more expensive to change.

Marginal on a petrol engine, the single chain is over stressed by the need to drive the fuel pump which provides extremely high pressures. The pump also presents a jerky load to its drive which chains generally dislike, especially with a poor design of tensioner.

Best - duplex roller or a geared drive (if you don't mind the noise). Well designed, this will last the life of the engine. Example - early M-B (meets the requirements of para. 2).

Reasonable - a well designed belt drive which is accessible for maintenance. One or two belt changes within vehicle life. Example - PSA HDi.

Worst - single or hy-vo type chain. Requires maintenance with costs out of proportion to vehicle value as the vehicle nears the end of its life. Example - some newer M-B, eg. old A Class.

Find out what sort of chain is fitted to this engine and report back - preferably with details of any modifications which BMW have made.

659.

Edited by 659FBE on 21/10/2012 at 19:09

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Mon 22 Oct 2012 16:26
BMW 1 Series 118d - BMW N47 Timing Chain - Grease_monkey

I went to have another look at the BMW today armed with more information about chain noise and the chain on the car is making a noise. Slight when cold but as it warmed up got very noticable. Not a BMW dealer i'm purchasing the car from but they have promised it will be fully repaired by BMW and offered me to test drive the car after repairs and if i'm still not happy i can walk away from the deal with my money back!! Can't ask anymore than that!!

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Mon 22 Oct 2012 16:42
BMW 1 Series 118d - BMW N47 Timing Chain - 659FBE

I've since had a look at the design of this chain drive and in my opinion, its long term chances of survival are slim. It meets none of the criteria for long life as outlined in my previous post.

Google "N47 timing chain failure" and see what you find.

I cannot reasonably advise you as to how you should spend your money, but buying a product which many people have found to have such a profound inherent weakness cannot be wise. There are plenty of diesel engines on the market from other suppliers which do not exhibit this problem.

659.

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