Ticking noise from the top end of 2.5 engine

[steve955i]

Noticed an occasional faint ticking noise from the top end of my 2.5 engine back in October. Thought it was a tappet but it's got louder now - especially on start up. Sounds like a singular noise emanating from the top end rather than the bottom. Any ideas? - thanks

[Brianmoooore]

Tappet sounds like a likely diagnosis to me.

[Moose1]

Hmm, got a ticking noise on my '90 316i... Thought it was the tappets as well, but spoke to someone about it the other day in conversation, they mentioned it needs "re-shimmying" - something to do with replacing a gaskety thing (not the head gasket). Not a pricey thing apparently so i'll be getting that done at some point. He reckons its not doing any harm so no rush. Could be the same for you, he had a 325.

[Brianmoooore]

I think "someone" doesn't know what he's talking about!
The M40 ('90 316i) engine uses (intended to be) hydraulic self adjusting tappets, not shims, which were intended to require no maintenance at all.
These were BMW's first attempt at hydraulic tappets, and unfortunately they weren't as successful as was hoped.
Anything over 60,000 miles without the tapping, at least some of the time, is good going.
You can experiment with different oil grades and even an engine flush, and you may get an improvement, but ultimately replacement is the only cure, although if you can live with the noise and comments from other people, it does little harm and has little effect on performance.
The 325i engine, on the other hand, has good old fashioned hand adjustable tappets, by rotating an eccentric disc.
This is a regular maintenance task, and shouldn't be left for too long, or parts will wear.

[Moose1]

Aaaah, ta for clearing that up!! mines done 154,000 and the noise is just about there, quite a result really i'd say!
Are you 100% sure about mine being an M40 though? i thought it was an M10, based on what i've read in Haynes manuals. Is there any way i can tell from parts numbers etc? It would certainly explain a few things thats for sure!!! (Apologies this isnt really my post, i kinda invaded it! )

[Brianmoooore]

Are you 100% sure about mine being an M40 though? i thought it was an M10, based on what i've read in Haynes manuals.

Well no, I can't be 100% sure from here, but if it was first registered in 1990, it had been sitting around unregistered for a couple of years! Unlikely at a time when BMW could sell every E30 they produced.
Distributor is right at the front of the engine at the top on the M40, and is right at the back of the engine, sticking up vertically on an M10.

[hongkongfuey]

Noticed an occasional faint ticking noise from the top end of my 2.5 engine back in October. Thought it was a tappet but it's got louder now - especially on start up. Sounds like a singular noise emanating from the top end rather than the bottom. Any ideas? - thanks

do you think it might be exhaust manifold gasket, that makes that sort of noise if its going?

[Moose1]

Cool cool, that makes sense to me... the distributor is at the front. Cheers fella.

[sam325is]

injectors

[snoops]

snapped exhaust manifold stud?

[freynolds]

Noticed an occasional faint ticking noise from the top end of my 2.5 engine back in October. Thought it was a tappet but it's got louder now - especially on start up. Sounds like a singular noise emanating from the top end rather than the bottom. Any ideas? - thanks

I've got this from the 325i I've just bought. It's done 177k miles, and I don't think it's always been looked after as well as it deserves - don't worry, I'm gonna give her the love she deserves now

I did the tappet adjustment today (boy is that fiddly!) After I was content they were all ~ 0.25mm clearance and had done an oil change at the same time I started her up and the tappet noise was the same or maybe more noticeble What's the reason for the clearance gap on the tappets?

I spent a while trying to identify exactly were the noise was coming from under idle -it seemed to be the front of the engine more than anywhere else. Could the distributor make this noise? I also tried the trick of using a metal bar to listen inside the engine, and no ticking noise was obvious from the rocker cover. There was more ticking noise from the inlet manifold. Can injectors make this ticking noise? Also, should they?

If anyone has any ideas let me know. Cheers[/i]

[Brianmoooore]

The injectors used on the 325 are an early design, and are noted for ticking.
Rev the engine and switch off the ignition. If the noise ceases immediately, it's the injectors. If the noise continues as the revs die, then it's not the injectors.
A blowing exhaust manifold gasket or a cracked exhaust manifold can also produce a tick which changes when you switch off the ignition.

[Dave_M3]

There's quite a tick developing in the iS over the last few weeks too, very bad on start up this morning.
Might try that reving and switching off the engine tomoro

[robbo86]

ive got a tick on my m40 heap.... which is quite audible in the cabin, my old man said it might be exhaust manifold gasket, but my mechanic said it does not sound like it...... now i am confused...

[bmwe30mtech]

ive got a tick on my m40 heap.... which is quite audible in the cabin, my old man said it might be exhaust manifold gasket, but my mechanic said it does not sound like it...... now i am confused...

Nearly always the tappets on the M40's.

M20's its often the injectors more than the rockers. Brians method is the best way of testing. That said, just adjust your valve clearances anyway its good to check they are all correct from time to time.

[freynolds]

The injectors used on the 325 are an early design, and are noted for ticking.
Rev the engine and switch off the ignition. If the noise ceases immediately, it's the injectors. If the noise continues as the revs die, then it's not the injectors.
A blowing exhaust manifold gasket or a cracked exhaust manifold can also produce a tick which changes when you switch off the ignition.

Cheers for the tip, Brian. I tried it out yesterday only to find that the noise died away gradually with the engine. So that's injectors off the list of possible culprits I suppose.

What's the easiest way to eliminate the exhaust manifold from the list? Listening closely to the engine bay while running at idle it certainly seems more intake side than exhaust if anything, but I wouldn't put much dosh on it!

[bmwe30mtech]

Place a screwdriver on the rocker cover roughly above where the rockers are located under it, and place the screwdriver handle to your ear. You wil be able to hear which ones, if any, need adjustment/are wron.

[dannyboy759]

The injectors used on the 325 are an early design, and are noted for ticking.
Rev the engine and switch off the ignition. If the noise ceases immediately, it's the injectors. If the noise continues as the revs die, then it's not the injectors.

Is this a problem?
And is it worth changing them as ive got this problem with one of mine.

[bmwe30mtech]

The injectors used on the 325 are an early design, and are noted for ticking.
Rev the engine and switch off the ignition. If the noise ceases immediately, it's the injectors. If the noise continues as the revs die, then it's not the injectors.

Is this a problem?
And is it worth changing them as ive got this problem with one of mine.

Injectors are expensive i think, you can get the old ones cleaned and new seals for quite cheap.

Its not a problem that injectors tick, perfectly fine.

Cam/rocker ticking again is fine, just an annoying sound. M20B25 engines should run a tiny bit ticky, otherwise the valve clearances are too small and your risk breaking a rocker.

[dannyboy759]

Cam/rocker ticking again is fine, just an annoying sound. M20B25 engines should run a tiny bit ticky, otherwise the valve clearances are too small and your risk breaking a rocker.

Thats another reason why you adjust them to 0.30