FG649 Cabin harmonics

[whatcharterboat]

Thank you john for you reply and suggestion.
I have doubled checked the bolt down of the hatch, the bolts all face up so they should be right. As I also have removed and replaced the seats I have double checked their bolts as well. They do not appear to be touching the engine, alternator etc. I have also since applied a layer of sound deadening paint to the wheel arches. Today I put the water tanks back in and I am close to being able to drive the Amesz again. Will let all know if moving the vehicle makes a difference. Thanks again
Steve

Hey Steve........ Mate, that's fine. I didn't have much for you other than that. Kerry's thought on the turbo shield was pretty good. We chased an engine noise for six months on an old 637 Canter back in the day. Turned out one of the boys dropped a Stanley knife down in under the exhaust manifold somehow and no one could find it. Haha.

Kind regards John

 

[NMC_EXP]

Everything has a natural frequency of vibration. If the natural frequencies of two connected objects are the same a resonant condition can result.

Engine and drivetrain and even tire lug patterns can cause a vehicle cab to resonate.

Assuming there are rubber mounts between the cab and frame you might replace them.

I worked a problem with track type excavators. The rubber compound used for the cab mounts was changed without doing any testing. Turned out the natural frequency of the rubber mounts matched at certain speeds the frequency of the track grouser bars as they struck the ground thus amplifying the vibration into the cab. End result was as they drove the excavators out of the factory building, the cab resonated so violently the glass popped out of the cab windows.

We changed the rubber compound used for the cab mounts and eliminated the problem.

 

[steve4wdaus]

Hi all
Finally reassembled my Amesz and took it for test drive today. Appears the harmonics vanished on moving of the truck.
Thank you for the help and the witty assistance
Regards
Steve