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.

[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!!"

[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!!"