BMW 740iL Timing Chain

DUSTINATOR4U2000

MEMBER
1974 BMW 740

I was told that my timing chain is going out or the timing belt im not sure if its a chain or timing belt or if there is 2 seperate timing mechanisms. There is a loud ticking coming from the engine. They also said I shouldnt change the oil because that could cause more problems. Is this a repair worth making? Do you recommend I dont drive it anymore?

5 Replies

BLACKOP555

MECHANIC
10,371 POSTS

If the timing belt or chchain is going out I wouldnt until it is fixed. If that goes out then say goodbye to the engine. Its a simple fix

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Saturday, October 20th, 2007 AT 12:42 PM

DOCHAGERTY

MECHANIC
9,601 POSTS

There is a timing chain in the M62 motor.
This might be a tensioner issue, and may be a lifter issue.
Without hearing the noise myself it is not possible to be accurate.
As far as being worth it, it is practically impossible to say
from where I sit.
Send me a PM and lets talk about it on the phone.

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Saturday, October 20th, 2007 AT 2:02 PM

SCOTT POOLE

MEMBER
1 POST

In my oppinion BMW made an engineering oops. Rather than use an idler gear, they use a guide rail to deliver the chain from passenger to driver side intake cam. The guide rail is "U" shaped and has alot of stress on the bottom of the "U". When the wear becomes excessive the timing chain tesioner piston becomes extended beyond its working range. The result is the tensioner looses its oil pressure. The determining factor would be to line up the two intake cams. If the cams are out of sync you have your answer. It is a costly repair to replace the guide, $2,500-$3,000. I found another solution.

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Saturday, October 27th, 2007 AT 6:33 AM

DOCHAGERTY