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Timing chain

Printed From: - BMW Owners Discussion Forum
Category: Technical & Model Specific Forums
Forum Name: BMW 6 Series
Forum Discription: This forum will deal with any issues on the BMW 6 Series (E24, E63 & E64)
Printed Date: 05-June-2020 at 00:31

Topic: Timing chain
Posted By: black m6
Subject: Timing chain
Date Posted: 12-July-2008 at 02:41
Has anybody got any idea of how to find out if the timing chain has been changed on M635.It has got a full service history mostly main agent and then BMW specialist.Phoned both agents up and they could not tell me if it had been done  not even though they serviced the car.I know that it should be replaced at about 100,000 miles.My car has done 140,000 and was last serviced about 150 miles ago there is no timing chain rattle and she is very smooth.I am just wondering that when the car was serviced at about a 100,000 miles by the dealer would they have replaced it anyway?I have got loads of bills for the car but no paperwork for the servicing though the service book is stamped up (30 stamps).Thanksangry1

Posted By: alpina17
Date Posted: 13-July-2008 at 12:43

If it had been done, would be documented, if that many stamps surely the previous owner would get same BMW garage to carry out the work. Some interesting reading below; - -

Posted By: Bayerische
Date Posted: 13-July-2008 at 15:02

I agree, if the work had been done it would probably have been documented as it is a very expensive job to get done and requires alot of new parts. If the previous owners were fastidious enough to document everything else, it is unlikly they would have forgotten the most important job on the engine. Costs vary from 1500-2500 depending on who does the work.

If there is no record of it then I would assume that it has not been done. A chain slipping on an M88 engine can be fatal and at 140000 miles it is 40000 miles overdue. If the head gasket looks new then perhaps it has been done, but I dont think I would take the chance.



Current: 1989 E24 M635csi
        1996 E36 323i coupe

Previous: 1989 E24 635csi
           2001 E46 330ci
           1987 E28 M5

Posted By: m3Cecotto
Date Posted: 14-July-2008 at 21:16
I'd assume that it hasn't been done until you can establish otherwise.

They can break - I have seen the evidence and it's not pretty, but I don't think I've heard of one going in about 10 years.  I think it's probably down to lower use - these cars tend to do 5000 miles p.a. at the most now and on that basis, it's a once every 20 years expense now.  Having said that for every broken chain, there is a tale of a car doing 200000 miles on the original chain.

The achilles heel is the plastic/rubber guides - these become brittle with age more than anything and wear, effectively increasing the length of the chain.  Additionally the sprockets do wear the chain does stretch - my chain was noticeably longer than its replacement.

The E46 M3 spring loaded tensioner is the oft recommended mod, and it does cure that occasional death rattle on startup, but I hear that there are now tales of premature chain weaa with these too - mostly on S14s.

Parts are about 950.  It's not a particularly complex job nowadays - and it can be done without removing the head, despite what the "marque experts" say.  2500 for a timing chaim and associated parts is taking the piss imo.

Would I do it in your position?  Probably not tbh.  It's not noisy and it's smooth.  Your car has a good service history and is now owned by an enthusiast, who will not skimp on maintenance. I'll bet you'll find few cars with full service histories and regular oil and filter changes that have suffered a broken chain.   I think I'd find a good running spare engine for 1500 and stick it under a bench just in case.

That way when you do eventually need a rebuild, you have an engine to keep your car going and you can sell it once your need has passed.

1981 E23 735i
1989 E30 325i Motorsport Cabrio
1989 E24 635CSi Motorsport Edition" rel="nofollow - Bavarian Retro Cars

Posted By: black m6
Date Posted: 16-July-2008 at 11:49
I think i will try and get in touch with the previous owners and see if i have any joy.If it needed doing i would get it done but she runs and sounds really well and it seems a shame to strip her down.I have got some expensive bills for other parts that have been done ie steering rack/shocks/exhaust/and other parts that i know that they have been replaced but have not got receipts for.I have also got a motorsport e30 convert and i know that the cam belt has been changed on the last service but is not stamped on the service book.I suppose it is the chance you take ,hope i dont end up paying the price.Thanks happy driving .

Posted By: Howard
Date Posted: 23-July-2008 at 22:00
I once sold an M6 that had 190+K on the clock that had never had the chain replaced to my knowledge. It rattled a bit, but still kept on running.
Last I heard it had done about another 50K miles with no new chain.
One reason that the cost is quoted at 1500 to 2500, is that when you have the head off, you may as well go the whole hog and fit anything else that looks like it needs changing. Whatever you do, make sure that if you change it, the person who does it knows how to do the job. A local guy with an M5 came to me a couple of years ago having just had his chain changed. Halfway through the job, the garage rang him up and said that it needed a couple of new pistons and some valves. When it came back, it leaked water inside. The owner offered it me for 2k, but I refused it. More fool me! He took it to a garage that I recommended, and it turned out that the head bolts just needed tightening up. However, I reckon that perhaps the original garage had set the timing wrong during the chain change. After all, it was running when it went in.

I guess that it all depends how much money you have in the car, and how long you propose to keep it.

Spare engines are OK if you can see them running before you buy them. Can you imagine the annoyance when your chain goes, you fit the spare engine and find that it needs a new chain?

The M6 from the 80's is a great car. Look after it and it should appreciate.

1963 700 LS
1988 635 CSi
1990 M635 CSi no longer!
2001 E38 728i Individual" rel="nofollow -

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