M42 timing chain life

[kevin316i]

Is there any particular reason why the timing chain should be replaced on a M42 engine if its running sweetly?

The car has just under 132,000 miles on the clock.

[E30Mark]

Nope!

assuming the sprockets are in good nick then the chain shouldn't slip, i don't know of a chain ever breaking!

Always worth putting in a new hydraulic chain tensioner once in a while, about £25 from the dealer.

[tim_s]

i would kinda agree with mark, but would definitely suggest that its a good idea if you're even the slightest bit worried to pull all the covers off and take a look for yourself. its a bit dramatic if anything fails there and so I think its a good precaution to check everything - would check all sprockets and guides for wear and check the chain for slackness etc, and check that the cams haven't moved off position due to chain stretch.

[kevin316i]

Thanks guys, there is a BMW specialist that I trust to check it for me, so if it needs any work for the NCT in November (Irish MOT) I'll get him to check it out for me.

[Pal318is]

My 318is has done 205,550 miles now, still go's ok and no real major problems, i had the chain, tensioner and sprockets done from my local stealer when the milage was on about 100,000 miles, having said that it was the stealers who recommended that the work was done (even though it fookin cost over £700)

So as the guys have already, should be sweet. If any one know's 318is's then it's Mark & Tim.

I only know a little

Pal

[jagtech2002]

i would definetely recommend fitting a modified tensioner, mine went t*t's up slipped a tooth and ended up bending the majority of the valves. OOP'S

[320Touring]

i would definetely recommend fitting a modified tensioner, mine went t*t's up slipped a tooth and ended up bending the majority of the valves. OOP'S

as far as i'm aware you can only get the e36 m44 tensioner from the stealers/GSF etc anyways. takes about 5 mins to change then 3 mins of worrying as it rattles its lil head off til it fills with oil

[koos]

I personally prefer chains to cambelts, I like reliability rather than decibels. M20 should have had a chain.

[tim_s]

i would definetely recommend fitting a modified tensioner, mine went t*t's up slipped a tooth and ended up bending the majority of the valves. OOP'S

as far as i'm aware you can only get the e36 m44 tensioner from the stealers/GSF etc anyways. takes about 5 mins to change then 3 mins of worrying as it rattles its lil head off til it fills with oil

i dont agree with this method at all, i always pop the tensioner out, as in the meantime you're letting the timing chain beat the hell out of the timing case etc and risking damaging the chain, damaging the timing cases, damagin the guide rails, risking chain slip etc.
really a v bad idea imo
also giving it more consideration, i'd def change the chain at 130k. jsut not worth the risk. you risk slack chain meaning bits of guide rail or bits of chain ending up in oil pump. m42 oil pickup gauzes are notoriously shit, engine wouldn't have to be massively noisy for any of that to happen - we're not talking terminal chain failure here. have seen a few timing chain related failures on an m42 normally ending up in seized oil pump, for what a chain costs i dont see the point in risking it.

i'd def properly inspect it all at minimum, and probably replace the chain and tensioner and a few odds and sods just as a matter of course.

[jagtech2002]

depends on if you are prepared too strip the front timing cover off as it isn't a particurlarly nice job, then you might encounter the problem of the water pump being seized solid to the cylinder head plus varius other seized parts,no dis respect to tim but if the car is running sweet as kev explain's why go to all the trouble?

[tim_s]

think timing chain life is supposed to be circa 120k in general. simple as that really - after 130k+ i think its time to look into it really if you care about your motor. in fairness my bro had an m42 years ago with 170k on it with original chain, it depends how much your car means to you. i guess ultimately its personal choice, if you're worried replace it, if not don't.

you might encounter the problem of the water pump being seized solid to the cylinder head plus varius other seized parts

timing covers easily come off, water pump can stay in place, and isnt attached to the head anyway dude! if you mean t-stat, which is attached to the head, that needs replacing every 2 yrs anyway, and can also stay in place when inspecting the chain so seized parts really are a complete non-issue.

[jagtech2002]

sorry man guilty as charged! it's just with my experience of m42's @ that mileage they can be a bit of a t**t

[mark_i]

timing covers easily come off, water pump can stay in place, and isnt attached to the head anyway dude! if you mean t-stat, which is attached to the head, that needs replacing every 2 yrs anyway, and can also stay in place when inspecting the chain so seized parts really are a complete non-issue.

so once the timing covers are off... how d'ya check the chain, sprockets and tensioner for stretch and wear?
my 1990 iS just clocked 180K km (+/- 110K miles) and is noisy from idle to 3500 rpm.

[tim_s]

tensioner you don't check - just replace. sprockets and chain is the same as checking stuff on a bicycle. the chain check for excess play and lateral movement, any front-back movement in the links/rollers etc and its def stretched. checking whether the cams have moved off is also a surefire way of telling the chain has stretched. the chains can also show damage to the rollers on really screwed ones. the sprockets will look sharpened and worn away if they are worn. the guides are important to check too, they can crack or just get really worn - metal chain on plastic means they eventually just wear.

[patrick85]

I've just stripped the timing case on my M42 to fix an oil leak and to inspect a noise. The noise used to come at 3000rpm and go again at about 3100rpm. Changed the tensioner a while ago and didn't help. Guide rails are worn so I think this was the problem but now I don't know if i'll replace the chain. Seems fine to me.

Timing chains do break. I've seen it happen.

I think I'll replace it.

Where you from Kevin, I'm Irish too.

[hammoj28]

Hmmm, how much would it cost to get a timing chain replaced? Mine was done at 76k just to keep it quiet iv been told.