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Vee Drive /Shaft knocking

greasemonkey

greasemonkey

Regular Contributor
Is this time for a rebuild or does the tranny sound like this!

http://www.youtube.com/user/captlazybone#p/u/0/rWi3HuAz7sw

Done some research in the install manual and seems a rough running engine,low idle causes this gear rattle and should go away with an elevated idle.The new mount I put on seems to vibrate on the rubber more than the 20 year old one I had to take off.I didnt have this in the water and also there is no backpressure
 
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'Gear rattle', which sounds like a spray paint can being shaken, is very common and is caused by torsional vibrations in the drive train. It usually disappears as more load is put on the system. There are couplings/drive plates available that minimize or eliminate it. Torflex is one of them. Another company makes spring type couplings that can eliminate it, but they want an engineer to do a vibration calculation on your power plant so that they can get it right. It is not harmful. I changed camshafts during my rebuild and got a huge dose of gear rattle. Diesels get it a lot. I've never heard of a stock gas engine with a stock spring type drive plate having this problem. It was hard to tell from the video, but your noise sounded a little too regular to be gear rattle. Good luck.
 
Was able to bump the throttle up and it went away,I think and hope the load is the cause.Coulda been low on the fluid.Learned alot about the Velvet drives and V-drives today.Got a 2.05 to 1 instead of the 1.91 to 1.Might make a deference I have no idea.Post a video up and see what you guys think.
 
Man, you've got some major coupling misalignment going on! I can see the shaft jumping about when it goes into gear.

Jeff
 
Are you sure your not looking at the clamp style coupling which isnt round?THe shaft Im sure isnt perfect but doesnt seem real bad
 
Unless my old eyes are tricking me, I saw the coupling jump to one side when you put it in gear, and back when it went into neutral. I know that aligning a Vee drive is a royal pain, but you need to at least check it.

Jeff
 
V-drives need a load on the prop or they make noise. If it still does it in the water it is usually caused by a misfire at idle.

Dan
 
my 79 silverton has a slight tick/rattle that is continuous at idle and the only time i notice it is from the top station through the shifter (i assume the noise travels through the cable) i wonder if this is the same thing?
 
As a jet boat owner I'm out of my element when it comes to v-drives. However, when jet pump bearing(s) fail, they can make a similar sound (via the impeller shaft wobbling within the unit).

I don't know much about the makeup of a stuffing boxes or bearings within the shaft assembly but could those be possibilities?
 
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Theres not a bearing where you see the rubber boot and the cutllass at the strut is a nitrile in brass sleve "bearing" but no ball bearings and is watercooled and lubed

I gonna say its gear lash and went away with acceleration or load Im sure the water load has a bunch to do with it
 
I agree with Dan and Jeff. Could be misalignment. A subtle misfire will do it too, and so will too low an idle. What is your idle set at in gear (pushing water)?
 
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