Cat 3304. What do you think the machine gun noise is in this video clip? 963 cat: http://youtu.be/Q56FrjHWU14
I guess the easiest thing to check would be the turbocharger, but it sound to heavy to be that. More like something in the valve line.
Transmission pump drive coupling to me??? if it was on a D6H/R on a 963 I would be removing the rocker cover. tctractors
Does it come and go like that all the time? I would install a manual oil pressure gauge, remove loosen fan belts or remove, if it doesn't change after removing belts, like Tc said pull valve cover and give it a listen, you could loosen injector lines one by one and see if it goes away, wrist pin. I've seen broken crankshafts make funny noises, Overworked, PS when did it start? Has it changed?
The noise starts after engine warms up just a little. does not go away. I'm pretty set on pulling the motor and rebuilding. 10k hrs on the meter...its time.
I second overworked's plan, seen minor accessories cause major noise, and broken/loose rockers, broken rocker studs
Could be engine expansion slap, pistons moving in the bores or worse, carbon expanding on the piston heads/head surface making contact. I would 'short' out the cylinders one at a time and see if any make the noise worse or to go away. That is to take the fuel line loose to the nozzle and allow that cylinder to miss with it at temp and some RPM where you know the issue is loudest.
If it is the older 3304 with mechanical injectors it could be one of them sticking after warming up a little i worked on one about two years ago and it finally stuck three or more down and it lets the rocker arm loose from push rod then it looses that cylinder and a lot of power. I am thinking this because from when i watched the video i am pretty sure i can hear engine change tones to when you hear that sound.this was a big problem i guess with the mechanical injected engines .
Sound s like its in the valve line to me for what that's worth. I did work on a D6H once that did this , turned out to be a wrist pin. I wouldn't pull it until I did a little digging around.