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emerald
emerald

Posted: Sat May 16, 2009 2:55pm

Post Subject: Technodrive Gearbox Whine

I have a 3 year old boat which has a Vetus 4.17 engine and Technodrive TMC60M gearbox, The box is by far the noisiest thing on the boat, being heard to whine loudly at all buty tickover in forward. there is no noise in reverse. The box was changed under warranty but the second one is no better. The driveline has a water sealed stern gland but no Centaflex type coupling (said by the engine fitter to be uneccessary) Anyone else had/cured this problem, or do I just buy a PRM 150? Mad Boater

Tony-B
Tony-B

Posted: Sat May 16, 2009 3:41pm

Post Subject: Technodrive Gearbox Whine

Dear Gil, I have to be very careful what I say here, so all I can advise is that you log onto www.canalworld.net and join the forum - its free. Then do a search on Technodrive and spend an hour or two reading the posts about the gearbox Vetus. If your shaft bearings are all Cutless rubber ones I might agree with your engine fitter because they will allow the shaft a certain degree of lateral movement, but if you have a greaser and/or a plain metal outboard bearing I would be very sceptical and I fear more wear on any plain metal shaft bearings than there would otherwise be. In fact I would want to remove as much shaft movement as I could from the bearings and gland so would fit an Aquadrive, but that may not be possible once the engine has been fitted. Tony Brooks

emerald
emerald

Posted: Mon May 18, 2009 1:01pm

Post Subject: Technodrive Gearbox Whine

Thanks for your prompt reply Tony-sounds ominous and intriguing. I shall follow your advice and join the site you recommend. Should I buy the earplugs now? Cheers Gil

Tony-B
Tony-B

Posted: Mon May 18, 2009 2:02pm

Post Subject: Technodrive Gearbox Whine

Not really ominous but you seem to be deciding between repair or changing for a different make so you need a good idea of what others have found. You are always welcome to email me (address in my profile) and then I can give a much fuller answer. Tony Brooks

emerald
emerald

Posted: Mon May 18, 2009 2:15pm

Post Subject: Technodrive Gearbox Whine

Tony, you are a mindreader!I am indeed thinking of a replacement and PRM seems the obvious choice. My previous boat had a PRM120 box which I was very happy with. Is that suitable for this engine as I think it will be tight to fit a PRM150. Thanks PS I have the water injection Vetus stern gland which I THINK you are saying means I don't need a Centaflex, but would that help with noise? Cheers. Gil

Tony-B
Tony-B

Posted: Mon May 18, 2009 4:22pm

Post Subject: Technodrive Gearbox Whine

I am sure the PRM will do admirable, but paler check with PRM first. There is a question about where the couplings on the two boxes are relative to the centreline of the engine because a box change may require the engine beds to be modified and I do not have the drawings to check. Now to the stern gland - Centaflex question. I accept your gland is inherently flexible so the gland end of the shaft is free to move in a lateral direction as the engine shakes about on its mounts (I assume the engine is flexibly mounted), but I have no idea what other bearings are in use in the stern tube. The Vetus manual for one of this type of seal (possibly not yours) http://www.vetusweb.com/manuals/files/Shafts/030 311.01%20r01%2011-07.pdf) refers to "the outer rubber bearing if fitted" but I have no idea if your outer bearing is rubber of plain metal. Vetus say the outer rubber bearing requires over 30 litres of water per hour fed into your gland assembly to keep it cool and lubricated. I can not see how a water scoop at canal speed would supply that so you may have a plain metal bearing and greaser. I have no idea. If you do have a rubber bearing just in front of the prop there is probably enough compliance in it to allow the shaft and gland to shake about with the engine so a flexible coupling is probably not required. However if its a plain metal bearing try this experiment. Make a rind with your thumb & first finger and grip a pencil or pen in it. Now try to shake one end of the pencil about. You will find it shakes easily. Now use your whole hand to form a tube and grip the pencil. You will now find any shaking about is very limited. This is what a metal stern bearing does to the shaft and in my view not fitting a flexible coupling could lead to accelerated wear in that plain bearing and noise/vibrations being transmitted to the hull. However I can not go against what Vetus say but I will say nothing would induce me to have such a stern gland (or gearbox) in my canal boat - it may well be different for river or sea work. If I was forced to have that type of setup I would want to remove as much lateral movement from the shaft as I could and this implies an Aquadrive or long Centaflex type coupling with its own thrust bearing but that is my not wholly trusting technology that has only been introduced to canals in recent years. I get uneasy when I am told on the QT that boat builders like Vetus engines because they supply the "whole kit" rather than having to source the stern gear separately. They may be fine products but ........... Without hearing the noise I can not be sure where it is coming from or if a flexible coupling will cure it. Going on what you say I rather doubt it will. Tony Brooks

emerald
emerald

Posted: Tue May 19, 2009 11:15am

Post Subject: Technodrive Gearbox Whine

Tony Thanks for another excellent and helpful response. I certainly have a water scoop which feeds the bearing in the shaft and, having seen the shaft when disconnected, I know it has lots of lateral free movement. Part of the lubrication requires applying silicone through a port. This gives me some confidence that the fitter was correct (he is employed by a Vetus distributor, so should know. However, it seems to me it would be a good idea to fit a single centaflex, anyway, although there isn't room to fit the Aquadrive or double Centaflex. That would give some more protection and wouldn't hurt the noise levels, either. First, though, I shall be looking into the PRM120 option, since from the web forum you recommended to me, it's only a matter of time until a new box becomes necessary. Thanks a bunch Gil

Tony-B
Tony-B

Posted: Tue May 19, 2009 11:56am

Post Subject: Technodrive Gearbox Whine

Dear Gil, that silicon grease is only for the seals in the actual sterngland (as far as I can make out) so if there is not other greaser you probably do have a rubber rear seal so the shaft should be able to shake about without causing undue wear. TB

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