Gearbox oil black...problem?

[parkstone bay]

Originally Posted by parkstone bay

Bukh DV24 see pic. I really like it. You'll note that the flywheel is at the forward engine of the the engine, gearbox aft. GB is is directly bolted onto aft of engine interfacing with the output shaft. There's no clutch or drive plate. I like simple.

.... "Forward End of the engine ..... " of course.

[parkstone bay]

Originally Posted by Uncle Bob

Hi, I am a little curious, given that the gearbox mounts to the rear of the engine on a spacer that encloses the drive plate, just how would the engine oil possibly enter the gearbox?

On the Bukh, there's no drive plate or clutch - I'd forgotten it was even possible to do things differently. See the pic. So while the gearbox does always "mount to the the rear of the engine" , the words "on a spacer that encloses the drive plate" aren't ALWAYS true. As I said, I'd forgotten that other engines are different.

[GILow]

Originally Posted by parkstone bay

On the Bukh, there's no drive plate or clutch - I'd forgotten it was even possible to do things differently. See the pic. So while the gearbox does always "mount to the the rear of the engine" , the words "on a spacer that encloses the drive plate" aren't ALWAYS true. As I said, I'd forgotten that other engines are different.

You might have forgotten, but I didn’t even know in the first place. Thanks, you have opened my eyes to a different (and mildly terrifying) way of doing things with boat engines. Mine, to date, have all been of the more conventional layout, mainly because they’ve all been converted truck or tractor engines.

[Sailmonkey]

Originally Posted by parkstone bay

On the Bukh, there's no drive plate or clutch - I'd forgotten it was even possible to do things differently. See the pic. So while the gearbox does always "mount to the the rear of the engine" , the words "on a spacer that encloses the drive plate" aren't ALWAYS true. As I said, I'd forgotten that other engines are different.

You’ve got a pair of clutch packs in your gearbox, no different than any other marine engine of this size. Your gearbox slips into a spline on the aft end of the engine. Like any other engine, I’d be surprised if it doest have a damper plate! So to have engine oil in the gear would require the failure of two seals, and oil migrating down a circuitous route.

Here’s an example of an engine that will have sump oil in the gear (because they’re the same)

[RaymondR]

Originally Posted by Uncle Bob

Hi, I am a little curious, given that the gearbox mounts to the rear of the engine on a spacer that encloses the drive plate, just how would the engine oil possibly enter the gearbox?

It wouldn't, it would go onto the flywheel and get flung out to the bell housing and drain out.

[RaymondR]

Originally Posted by parkstone bay

My engine has the gearbox bolted direct to the output shaft at back of the engine: (flywheel is on front, no clutch or drive plates). I'd forgotten that some engines have a different arrangement.

Common arrangement on speed boats where auto engines were used. Lets the engine be mounted lower in the boat.

[GILow]

Originally Posted by Sailmonkey

Here’s an example of an engine that will have sump oil in the gear (because they’re the same)

Attachment 221445

Mercedes OM636?

[Sailmonkey]

Originally Posted by GILow

Mercedes OM636?

The often lovingly called “atomic bomb”. The Universal Atomic 4. A 4 cyl flathead engine with an updraft single barrel carb, buried beneath the intake so that when the float fails you’ve got a bilge full of gasoline (petrol to the other English speakers).

[GILow]

Originally Posted by Sailmonkey

The often lovingly called “atomic bomb”. The Universal Atomic 4. A 4 cyl flathead engine with an updraft single barrel carb, buried beneath the intake so that when the float fails you’ve got a bilge full of gasoline (petrol to the other English speakers).

Oops, got my wires crossed. Yes, now I recognise it.

They seem to have a loyal following, despite their incendiary propensity.

[svbravo]

Hi all. Thanks for the response. At this point, I think the best thing to do is to start with an oil analysis. I'm thinking that the cause of the overheating must be friction in the clutch plates, hopefully the analysis will help in determining that. There is an oil cooler on this gearbox, so it's hard to see how else the oil could get that hot. Once we figure out the cause of the burned oil (yes, it does have a burned smell), we can figure out how to stop it, as obviously the engine/gearbox is under warranty. Hope it doesn't become an arm wrestle, but I'm trying to stay positive that we'll get it resolved quickly.

[GILow]

As noted, check the position of the gear selector arm when the throttle is engaged. If it is set wrong it will, most likely, void your gearbox warranty, in which case you’ll have a case against whomever commissioned the engine. So take photos, make records etc.

[svbravo]

Originally Posted by GILow

As noted, check the position of the gear selector arm when the throttle is engaged. .

Interesting. Now I get the significance of your earlier comment about actuator angle. Sorry I missed it before. So if the Morse cable is not correctly adjusted to align with the stops for forward and reverse, this could cause continual clutch slipping when the gear is engaged, leading to the overheating?

If this is the cause, and the builder corrects it now, is there any way to determine if any permanent damage has been done?

Thanks

[Wotname]

Originally Posted by svbravo

Interesting. Now I get the significance of your earlier comment about actuator angle. Sorry I missed it before. So if the Morse cable is not correctly adjusted to align with the stops for forward and reverse, this could cause continual clutch slipping when the gear is engaged, leading to the overheating?

If this is the cause, and the builder corrects it now, is there any way to determine if any permanent damage has been done?

Thanks

If this proves to be the reason for the black oil, then the permanent damage is the amount of wear of the clutch. It can only be properly ascertained by measurement i.e. pulling the gearbox / clutch apart (AFAIK).

The good news is - it has only occurred for 50 hours; the bad news is - it must be slipping a lot to get that bad in 50 hours.

Did the builder commission the engine installation or some one else?

[GILow]

Originally Posted by svbravo

Interesting. Now I get the significance of your earlier comment about actuator angle. Sorry I missed it before. So if the Morse cable is not correctly adjusted to align with the stops for forward and reverse, this could cause continual clutch slipping when the gear is engaged, leading to the overheating?

Yes, at least that is my understanding from the installation instructions that came with my Beta engine, fitted with a TMC manual gearbox.

Wotname has the best answer on the wear question.

I assume you didn’t install the engine and gearbox yourself, hence my advice to photograph/video the alignment if it is a problem as you may need it for the warranty claim. If you did install it yourself... well, painful lesson and hopefully the damage is not too bad (as per Wotname’s remark about the low hours.). I did my own install, so all this stuff has dominated my thinking these last few months.

[jimbunyard]

Originally Posted by svbravo

Hi all. Thanks for the response. At this point, I think the best thing to do is to start with an oil analysis. I'm thinking that the cause of the overheating must be friction in the clutch plates, hopefully the analysis will help in determining that. There is an oil cooler on this gearbox, so it's hard to see how else the oil could get that hot. Once we figure out the cause of the burned oil (yes, it does have a burned smell), we can figure out how to stop it, as obviously the engine/gearbox is under warranty. Hope it doesn't become an arm wrestle, but I'm trying to stay positive that we'll get it resolved quickly.

Barring unknown information, with only 50 hours, I'd start with a call to the manufacturer...