Universal M-30 Clanging Noise

[Quadrille in JB]

The clanging is definitely metal on metal. A repeats for about 15 seconds and subsides soon as I raise the RPM

[DougR]

What is the idle RPM?

[motretu]

sounds like it's time to get an automotive stethoscope [harbor freight] to pin down exactly where the sound is coming from..

i'd like to know cause I have a M30 in my CC33 [front of engine faces aft, with V drive], with no such symptoms..

[Quadrille in JB]

After being on the boat all weekend I determined that every time the boat is shifted into forward it makes the metallic clanging noise until the RPM is raised above 1500. The idle speed is 900 RPM. It doesn’t have to be shifted from reverse first.
It was a great weekend for sailing with 10 kt winds ar 73 deg F.

[Diesel Bill]

Seems like you've gone through all likely culprits. Could it be lower RPM harmonics shaking every thing bolted to the engine? Or something in the Fwd trans clutches or drive? At this point without actually being there and experiencing it all I can do is guess.
Looking fwd to a short video with good sound. Do let us know if you figure it out.

[fish53]

Pull the dipstick from the gearbox and smell the fluid, if it smells burned it may be a broken clutch plate, I'm assuming you checked the flywheel bolts when you changed the drive plate, I have seen them loosen. You really need to be in attendance when it's put in gear, you can do this tied to the dock and shifting right at the gearbox while you watch. I have a spare HBW100 1.79 to 1 if that helps.

[Quadrille in JB]

http://https://youtu.be/xJ0BxJI-Xv4

Thanks for all the great comments. I drained the transmission while I was changing the torque plate and the fluid was clean with no metal. I checked again today and everything looks good.
I took a video today of it running. The clanging doesn’t start until about one minute 40 seconds into the video. Sometimes it’s louder than this.
All,comments are greatly appreciated.

[boden36]

Assuming it is not that loose cable end rattling against something, have you made sure that none of the bolts on your flexible drive are projecting enough to come close to the back end of the box?
I had something similar recently on a car disk brake where a misplaced washer changed clearances just enough to make an intermittent contact.


Regards,
Richard.

[Quadrille in JB]

It was clanging before I installed the anti-vibe coupler.
And, the noise is a lot louder than a loose cable.
Thanks for the input