Help !!!! Hammering sound in my Engine M30!!

[grave77]

I was testing a chip without a maximum RPM shutoff and I stepped on it to reach more than 7000 while the engine was still cold!! … so silly but I just forgot about it since I was anxious to know the chips results.

Now I have this hammering sound in the engine with a ticking sound too. It sounds out every engine rotation.


Is it the camshaft? Or the crank shaft? Pls advice . !!!

[Badkrma]

Pull the plugs and see what they look like. See is one of them is beat to hell. Valve is what I would think.

[grave77]

that means that the least is to pull out the head !! it's night time now .. I need to wait till tomorrow then ... but what if the spark plugs r ok ... ?

[Martin in Bellevue]

A few m30's on this board (& mye28) have over-rev'd, snapping the rocker.

There's not much more in an unblown m30, beyond 6k rpm.
http://www.bimmer.info/bmw/Martin5er/dyno535Nov04.jpg

[Jose]

I don´t think you´ll be able to see much of a spark plug in this case as it´s been too short time ago. Reving a M30 over 6200 rpm without stronger valve springs is asking for trouble even with a warm engine.At such high rpm the piston could collide with the valve, due to the std valve spring not being able to put up with the enormous speed the camshaft is rottating, thus not being able to close/retract the valve in time. Take of the valve cover, rotate the engine by hand and check visually for rockers without full movement and try to feel at the time you´re rotating by hand if there are any obstructions at the time of reaching tdc at each cilinder ( a lightly bent valve could be felt as a small resistance). Remove your plugs for better feel. Good luck mate, you´ll need it this time for sure.

[George M]

Agree with the above. We talked about max. reving the M-30 on old valve springs before...not a good mix. No reason to take a M30 above 6K as Martin said. I am not a big fan of raised RPM shut off on custom chips particularly on a 100k mile motor.
If anything is broken...which it sure sounds like...including a rocker arm you can see with the valve cover off, the head has to be removed for repair.
George

[grave77]

just to make things clear ... the rocker is the piece of metal that transmittes the camshaft torque to the valve to open? ( the rocker pushes the valve ) ?

[Jose]

yep, that' s the one.

[grave77]

by the way, the engine still runs as smooth as before ... smooth idle ... "with the sound!!"

[632 Regal]

spun a bearing, lack of lube at high rpms with cold non flowing oil...what oil are you running?

[winfred]

if you can't find anything with the valve cover off there may be bottom end dammage like a spun bearing, you can drain and strain the oil looking for copper/silver looking flakes, that would mean a bad bearing


by the way, the engine still runs as smooth as before ... smooth idle ... "with the sound!!"

[grave77]

synthatic oil 10,000 Km still 8,000 Km left ...

[Paul in NZ]

synthatic oil 10,000 Km still 8,000 Km left .

not now my friend :(

ouch sorry about that

a standard m30 goes flat as a pancake at just over 6200 when the rpm limiter cuts in...prolly just before valve bounce,as i found once passing a dude on a short uphill passing lane

[grave77]

Well ... I feel like I will replace the engine ... removing the head will cost 80% of installing a good condition second hand engine. therefore I will run the engine untill it dies maybe I will learn from it more than wasting time fixing it ... do u agree guys?

[632 Regal]

maybe you just bent a couple valves and its hammering into the guides??? heavy metal sound isnt good none the less. maybe with a lot of good luckits something stupid??? naww its trashesd, I would however like to see you start takin it apart finding whats wrong before replacing the deal. Never know man.

[Paul in NZ]

problem with a usedengine is just that...how "used" is it,i would fix the one you have got,my bet is a top end problem.....

[Rory535i]

problem with a usedengine is just that...how "used" is it,i would fix the one you have got,my bet is a top end problem.....

I broke a rocker arm on my M30 and it made a similar noise but I also had a considerable loss of power as the exhaust valve wouldn't open on that cylinder. I still managed to drive it 20 miles back home and I was quite suprised how well it ran on 5 cylinders! They're great engines. My original cam and rockers saw close to 150,000 miles before it gave up. When i took the head off i was pleasantly suprised to find out that it had been given a bottom end rebuild quite recently because I could still see the hone marks in the cylinder bore. Now with the new cam i now that i have a bomb-proof engine for another 100,000miles!

[Derek A.]

You might want to try and hook up a mechanical oil pressure gauge on the motor and see what kind of pressure you are getting. m30 is usually about 80psi cold with 15w50 oil in it. If you see a huge drop or the gauge is bouncing all over the place, chances are you hurt something on the bottom end.

First things first - pull the valve cover and watch the rockers arms as the engine is cranked - make sure that evertything there is in good shape.

[grave77]

well now I have a clear idea about what to do ...I'm going today to the mechanic to see whats going on... I will take pictures to keep in Bimmer archive. I will also change the head screws to Trox instead of Hex type before summer time. Hex screws r a timed Bomb !! by the way I drove her today around a 130 miles ... with speed 125m/h still running smooth ... this M30 engine is a Tank engine ... wish me luck guys ... :)

[winfred]

they almost never wear off the marks, i've done dozens of bmw head jobs and they all have hone marks, i did one that had 311k miles on the orignal bottom end that had most of it's hone marks


i was pleasantly suprised to find out that it had been given a bottom end rebuild quite recently because I could still see the hone marks in the cylinder bore.

[winfred]

the m30 hex are not the problem that the m20s are, different bolts completely


I will also change the head screws to Trox instead of Hex type before summer time. Hex screws r a timed Bomb

[Jeff N.]

Maybe one of the eccentrics was a bit loose and opened up some. That would give you a nice clatter in the top of the engine.

I'd go around and check all my valve clearances before I did anything else.

Jeff

[grave77]

well ... that was the reason, the valve adj. on the rocker was lose I re-gapped the valves and started the engine ... it was all smooth. seems like at the high RPM the rotating adj. on the rocker turned to protect the valve from being bent. anyway ... its done now ... am happy that nothing much happend in the engine. ..................... thanks guys ur da best :)