Noisy Tappets solutions? M40b16

Post Fri Jun 20, 2014 10:10 am

I've developed noisy Tappets.
Usually when the car fires up then it goes to a more subtle tapping and will go from completely quite to subtle while
I drive.
What can I do about this? I've done an oil and filter change and it hasn't made a difference.
Anyone got some tricks? Or do I need a louder exhaust and music to drown out the sound.

Post Fri Jun 20, 2014 10:24 am

How well does the car rev up? If you have trouble getting over 4500-5000 RPM then it's likely that your cam has turned into a Toblerone, and signals the economical death of your engine.

Otherwise, your tappets have been oil-starved. Read this:

http://www.e30zone.net/e30zonewiki/inde ... sy_Tappets

Post Fri Jun 20, 2014 10:39 am

I will have a look under the rocker cover when I get a chance next week. How common is it that the spray bar is the problem?
Trouble is BMW thought it would be better to have a massive analogue clock instead of a rev counter in my cluster to compliment the other analogue clock on my centre console.
Also I heard myths of putting thinner oil in can solve the problem.. I guessed this was just a quick fix to get around a bigger problem like a blocked/clogged line somewhere (relevant to the spray bar?)

Post Fri Jun 20, 2014 10:41 am

It seems to rev fine though. Never had a small 1.6l before and it doesn't dissapoint so don't think there's a problem there.

Post Fri Jun 20, 2014 1:51 pm

pauljsc wrote: Trouble is BMW thought it would be better to have a massive analogue clock instead of a rev counter in my cluster to compliment the other analogue clock on my centre console.

I very much doubt if BMW is responsible for this. Far more likely that someone has swapped in an early 'poverty spec.' cluster at some time.
The tappet noise you describe is just that - noise. It doesn't signify a worn cam (although these are fairly common on badly maintained examples of this engine).
The tapping has little effect on performance, and doesn't cause any problems, except attract comments such as "your big ends are knocking, mate" from the uninitiated.
Depending on whether the tappets are clogged or worn, cleaning the engine for a few months with a high detergent diesel engine specific oil, coupled with experimenting with oil viscosity may give some improvement.
Worked for the blue one in my sig.

Post Fri Jun 20, 2014 8:12 pm

Hmm that's good to know about the cluster! I wouldn't mind having a rev counter again at some point.
By cleaning do you mean removing and leaving to soak for a few months?
Ill check under the rocker cover in a week and also try a thinner oil.
Thanks for the help guys!
If all else fails I might consider a m42b18

Post Sat Jun 21, 2014 11:28 am

I mean running the engine with oil intended for diesel engines. Because the filthy excuse for a fuel produces so many contaminants and pollutants, the oil needs to contain extra detergents to cope with the mess.
These hydraulic tappets were BMW's first attempt at self adjusting cam clearances, and it wasn't 100% successful long term.