All,

Was speaking to a former six pot BM owner lately, who mentioned that the Timimng chain on the six pots has to be changed @100,000 miles.

Anyone ever hear this before?

More applicable to the "M" cars' engines, esp. the M88 24-valve, rather than the standard 12-valve 6-cyl.

Having said that, the cylinder head on some 6-cyl engines, e.g. the M30, should ideally be checked at about 130,000 for camshaft wear, worn rockers/tappets, failing head gaskets (oil in the coolant type of thing)

Oh boy have we heard this one !

As the horse says, it been discussed at great lengths in the M power forum, do a search, turned out to be quite a passionate subject with strongly held views on both sides.

I think I remember reading something in the FAQ section too.

Drew540i wrote: The only timing chain that NEEDS changing at 100k is the M635CSi and E28 M5 (except USA and catalyst cars which have duplex chains).

This is the M88/3 engine, which was given a single-row chain. Changing the chain is an engine-out job, which is likely to cost the thick end of two to two-and-a-half grand, unless you are talented / miserly enough to do it all yourself.

If you use your car every day, which I did until very recently for work, then that 100,000-mile / two grand mark comes up quicker than you think. It's the main reason why, in 2000, I stuck with my '83 635CSi rather than take on a 172,000-mile 1986 M635CSi which had been offered to me for three grand (the body was also not particularly good).

US & catalyst cars will generally have the S38 engine which has a double-row chain (the M30 12-valve also has a double chain).

It is not inconceivable that one or two of the cars which originally had the M88/3 might have been converted to the S38, e.g. one or two M635CSis which now bear the E34 M5 engine. In theory, the S38 conversion would be sensible in terms of peace of mind, but there is also the unavoidable cost of doing it.....

Your choice.

HORSETAN WROTE:

"the M30 12-valve also has a double chain"

Not every M30 engine has got double chain .I know that 3430cc engines have got single ones , 3453 cc on pre1982 has got double(or not...Now i am scratching my had...).My 3,3 L Automatic has a double chain....

Anyway , Total BMW and also BMW car magazien did "definitve" articles about weak chain engines...

S14 with big mileage usually has rattles from the chain ...But no dealers or specialist they contacted  have ever seen a broken chain...The cure for the noise is to remove old chain tensioner and put E36 M3 evo tensioners,They were told it 's a really good improvement...

M88/3 need timing chain at 160 k kms or 100k miles , in Italy there's the mighty "100k kms for a chain"(in Italy 100k kms are seen as a bad mileage...It' a strange idea coming from a mental brain...).No S14 nor M3 e36 evo tensioner can fit those engines, despite they are closely imparented with S14 ...

S 38 : over 200 k miles a chain and other important stuff  is normal routine...but not 100k miles.

E36 M engines naver had those problems ...

M5 E34 engines, 3.6 or 3.8 ,never had those problems...

M5 E39 : it's too early to say if their engines are affected...

I like to add M1 M88/2 : if You have enough money that You can buy and afford one, I think a chain swap is the smaller problem for your wallet ....

Francesco from italy

siscobmw wrote: Not every M30 engine has got double chain .I know that 3430cc engines have got single ones , 3453 cc on pre1982 has got double(or not...Now i am scratching my had...).My 3,3 L Automatic has a double chain....

That 3453cc unit was technically the M90, no?

My M30 3430cc unit is a double-row, not single.

Horsetan wrote:

"My M30 3430cc unit is a double-row, not single."

Are You sure?

I have a single one.It's a 3430 cc unit...and I only saw single chains on late M30 engines, 32, and 34, liter  turbo units on 745is E23....

SiSco from North Italy

My last car a Vauxhall Senator 3.0i 24v needed new timing chains anywhere between 100,000 and 150,000 miles and this was also a good time to replace the big Vauxhalls other weak spot the CHG.  This would have cost me about a grand and the car was only worth £300! So naturally when I bought the E39 I made a few enquiries about life of a 6 pot timing chain and was told they should last about 400,000 miles.

My M52 engine has 3 chains in it. Crank to exhaust cam, exhaust cam to inlet cam and crank to oil pump.  Needing 3 chains on an engine like this when it gets older would write the car off!

Aren't most of the problems associated with timing chains breaking due to the fact that either the hydraulic tensioner and or the plastic guards break/malfunction and cause the chains to stretch/snap/mangle 12 of your valves?

Andrew

Dont wish to upset anybody here

But the m30 3430cc uses a single row chain not a double , and it is so under stressed that to change it at 100,00 miles would be pointless in most cases.

E34 M30 535i SPORT



                                

micky_h wrote: I would say only if it starts to rattle, and if that happens on a simplex chain get it done asap coz they are prone to snapping.

Do you know in all the years that i have had BMW`s and been around BMW`s i have never heard of one of these chains snapping.

E34 M30 535i SPORT



                                

i'm just at 120k now so I'm screwed if that guy is right...

read somewhere anywhere between 150k-200k is recommended, but it wasn't a manufacturer recommendation, just another forum.

What are the typical costs associated with getting them replaced?

I Think You have to remove engine, if you want to do it without fuss....

I know that rattles on a simplex chain are symptoms of a highmileage engines , but I recently gave away-as a present of how great M30 engines are..and because I needed space- a 3430cc 735i engine,with 985k kms , the last oil service done a lot of hundreds kms before-from about 300k kms only adds of oil and coolant fluid, if I remember correclty- ...The engine was a everywhere-rattle , so I can't say the only noise I heard of was the chain....But chain did not snapped.Well after almost 1 million of kms, I wouldn't revv that engine to redline....but the engine was still running with a smooth idle at 800rpm with A/c on, before I parted the 735i out,and despite it was idling with a big blue smoke on exhaust....

Francesco from North Italy