2UC reversing gearbox drain plugs

[jenevers]

Just draining the old oil out ready for cruising. Each of the 3 plugs in the reversing gearbox, is a different size and 1 has a hollow stem (to collect crud I guess). I know where each 1 came from but, as they all have the same size thread, how do I know they where in the right place to start with???

Thread length first then head depth they are the following sizes.....1/2" hollow stem with 1" head, 3/4" with 1/2" head, 3/4" with 3/4" head.

I would guess that the hollow plug is the "dirt sump"plug (middle position) but if anyone knows the correct positions I would be grateful. Gardner's did everything for a reason!

[Timleech]

The hollow one should not have been removed, it locates the bottom pivot for the brake shoes (AFAIR).

Good luck putting it back

 

Tim

[jenevers]

The hollow one should not have been removed, it locates the bottom pivot for the brake shoes (AFAIR).

Good luck putting it back

 

Tim

But Er, but Er, the manual says the 3 drain plugs must be removed and the diagram shows flywheel sump, dirt sump and main oil sump, and those are the ones I've removed. Are you saying the 3 drain plugs should all be solid?

[Timleech]

But Er, but Er, the manual says the 3 drain plugs must be removed and the diagram shows flywheel sump, dirt sump and main oil sump, and those are the ones I've removed. Are you saying the 3 drain plugs should all be solid?

 

Sorry, I'll take that back, I was just working from memory and have no memory of hollow drain plugs.

The brake band locator is actually a stud, with nut underneath.

Possibly the hole was for a magnet.

 

Edit, my parts list gives all three as the same part number,

 

"Plug, faced, 1/2" BSP x 7/8" x 5/8" Hex"

 

Tim

Edited March 13, 2015 by Timleech

[jenevers]

Sorry, I'll take that back, I was just working from memory and have no memory of hollow drain plugs.

The brake band locator is actually a stud, with nut underneath.

Possibly the hole was for a magnet.

 

Edit, my parts list gives all three as the same part number,

 

"Plug, faced, 1/2" BSP x 7/8" x 5/8" Hex"

 

Tim

Phew! You had me worried. I'll check my parts catalogue too (forgot I had one)

Just checked and mine says 1/2" BSP x 7/16" x 5/8" Hex 3off.

So why have I got 3 different different ones and why is one hollow??????

Edited March 13, 2015 by jenevers

[Tony Dunkley]

Phew! You had me worried. I'll check my parts catalogue too (forgot I had one)

Just checked and mine says 1/2" BSP x 7/16" x 5/8" Hex 3off.

So why have I got 3 different different ones and why is one hollow??????

 

I would think the originals have either been damaged or lost and been replaced with anything that would fit.

[Timleech]

Is the hollow one a banjo bolt?

 

I agree with Tony, basically they're just 1/2" BSP parallel plugs, anything fitting that description will do the job.

 

Thes boxes were often piped up from the drains to a manifold on the side, so that each point can be pumped out in turn.

That required banjo bolts.

 

Tim

[swift1894]

Is the hollow one a banjo bolt?

 

I agree with Tony, basically they're just 1/2" BSP parallel plugs, anything fitting that description will do the job.

 

Thes boxes were often piped up from the drains to a manifold on the side, so that each point can be pumped out in turn.

That required banjo bolts.

 

Tim

No it's not a banjo. It's a steel bolt with a half inch long thread and a 1 inch long hex head. The hollow section is a good inch deep. I think it must be like that so crud can collect or originally had a cylindrical magnet inserted to attract scarf.

[The Pipe]

No it's not a banjo. It's a steel bolt with a half inch long thread and a 1 inch long hex head. The hollow section is a good inch deep. I think it must be like that so crud can collect or originally had a cylindrical magnet inserted to attract scarf.

I hope the magnet is not attached to another part of the gearbox. Sorry I'm a budle of joy this morning...

Edited March 15, 2015 by Jim Evans

[swift1894]

I hope the magnet is not attached to another part of the gearbox.

So do I! And more than you do!!

[The Pipe]

So do I! And more than you do!!

Not really giving you a good time are we there's Tim telling you you've just pulled the vital bolt out of the gearbox so it falls to pieces and now I give you great joy of having a magnet about to launch itself into the gears. Have you ever thaught of a PRM?

[swift1894]

Not really giving you a good time are we there's Tim telling you you've just pulled the vital bolt out of the gearbox so it falls to pieces and now I give you great joy of having a magnet about to launch itself into the gears. Have you ever thaught of a PRM?

What as opposed to a Gardner??????

[Tony Dunkley]

If this suspected 'missing' magnet does end up by wrecking your box, there is at least some consolation in that if you replace it with a PRM you'll have a much better gearbox than before.

The 2UC was alright on fishing boats and the like that ran for most of the time in ahead and made little and infrequent use of astern gear. For inland work such as barges it was a very poor box because it couldn't take the amount of astern use that the bigger boxes (3UC) would stand.

I reckon you should just put the plugs back in, fill it with oil and stop worrying . . . . . after all, you weren't worried before you drained the oil, were you ?

[Timleech]

If this suspected 'missing' magnet does end up by wrecking your box, there is at least some consolation in that if you replace it with a PRM you'll have a much better gearbox than before.

The 2UC was alright on fishing boats and the like that ran for most of the time in ahead and made little and infrequent use of astern gear. For inland work such as barges it was a very poor box

 

I imagine that it based on experience with the 2UC as fitted to 6LX and above, shouldn't really be an issue on the likes of 2/3 LW or L2.

I think you're trying to get him worried again

 

Biggest problem with the Gardner boxes in my experience is that it's so horrendously expensive to overhaul them if they do fail.

 

Tim

[swift1894]

If this suspected 'missing' magnet does end up by wrecking your box, there is at least some consolation in that if you replace it with a PRM you'll have a much better gearbox than before.

The 2UC was alright on fishing boats and the like that ran for most of the time in ahead and made little and infrequent use of astern gear. For inland work such as barges it was a very poor box because it couldn't take the amount of astern use that the bigger boxes (3UC) would stand.

I reckon you should just put the plugs back in, fill it with oil and stop worrying . . . . . after all, you weren't worried before you drained the oil, were you ?

Blimey I'm surprised to hear that a 2UC could be regarded as small. It's bigger than most modern narrow boat ENGINES!!!

 

I don't think there ever was a magnet, and even if there was It wouldn't be able to defy gravity and get off the bottom of the sump, which is steel and therefore would attract the magnet.

Magnet.

I imagine that it based on experience with the 2UC as fitted to 6LX and above, shouldn't really be an issue on the likes of 2/3 LW

 

Tim

Arghh!........ It's a 4LW

[The Pipe]

 

 

Biggest problem with the Gardner boxes in my experience is that it's so horrendously expensive to overhaul them if they do fail.

 

Tim

Biggest problem with Gardner boxes you a 3 foot longer boat to fit one for the same amount of cabin space, never seen anything so large.

[Tony Dunkley]

Blimey I'm surprised to hear that a 2UC could be regarded as small. It's bigger than most modern narrow boat ENGINES!!!

 

I don't think there ever was a magnet, and even if there was It wouldn't be able to defy gravity and get off the bottom of the sump, which is steel and therefore would attract the magnet.

Magnet.

 

Arghh!........ It's a 4LW

 

As Tim indicated, the 2UC box was shortlived when used on (inland) commercials with 6's. For pleasure boating with a 4 cylinder you're unlikely to wear it out in a hurry. Nothing lasts forever, and your box will work until it stops working, and there's nothing anyone can do or say to change that, but your box will be/is working relatively few hours compared with commercial use, very rarely transmitting anywhere near the power it's rated for, and all in all it has a very easy life.

So, as I said before, put the plugs back in, fill it with fresh oil and stop worrying.

 

Nb. Gleniffer engines were tried out at one time in a few barges, the engines were fine but they were let down by the gearboxes. Same problem as the small Gardner boxes, alright at sea running ahead for virtually the whole time, but they couldn't stand up to the amount of frequent full power use in astern that came with working locks.

Edited March 15, 2015 by Tony Dunkley

[swift1894]

As Tim indicated, the 2UC box was shortlived when used on (inland) commercials with 6's. For pleasure boating with a 4 cylinder you're unlikely to wear it out in a hurry. Nothing lasts forever, and your box will work until it stops working, and there's nothing anyone can do or say to change that, but your box will be/is working relatively few hours compared with commercial use, very rarely transmitting anywhere near the power it's rated for, and all in all it has a very easy life.

So, as I said before, put the plugs back in, fill it with fresh oil and stop worrying.

 

Nb. Gleniffer engines were tried out at one time in a few barges, the engines were fine but they were let down by the gearboxes. Same problem as the small Gardner boxes, alright at sea running ahead for virtually the whole time, but they couldn't stand up to the amount of frequent full power use in astern that came with working locks.

So what actually wears out on a 2UC (and what does UC stand for?)

[Timleech]

(and what does UC stand for?)

 

Unit Construction.

They bolt straight on to the engine crankcase.

Earlier Gardner boxes were separate, with a shaft input. The engine and gearbox were, separately, bolted to the same cast iron bedplates. The equivalent size to the 2UC was the 'No2 Conic Drive'

Edit - they were fitted to early versions of the L2, as well as some Gardner semi-diesels.

 

Tim

Edited March 15, 2015 by Timleech

[Tony Dunkley]

So what actually wears out on a 2UC (and what does UC stand for?)

 

For inland commercial use on 6LX's the astern gear on the 2UC box didn't last long, with rapid wear of the stuff that makes the howling noise, ie. the small astern bevels and bearings, closely followed by the driving and driven main bevels. The brake band was also prone to wearing fairly quickly.

Something to bear in mind with both the 2 and 3(UC) boxes is that the oil pump is driven off the output shaft, and with the engine idling in neutral there is nothing being pumped round the internal lubrication system, so avoid excessively long periods of running the engine out of gear, and if you have to do so then clutch in for a minute or so after no more than half an hour.

Another point to note with regards to the oil pump and lubrication system is that if tied up with the engine stopped and box in neutral in a current or tide strong enough to paddle the prop round, then the oil pump will empty the gearbox sump into the flywheel sump and the box will be running dry for the first few minutes after the next start up.

[Timleech]

No2 Conic drive box, from the MPS website:-

 

 

Tim

[swift1894]

For inland commercial use on 6LX's the astern gear on the 2UC box didn't last long, with rapid wear of the stuff that makes the howling noise, ie. the small astern bevels and bearings, closely followed by the driving and driven main bevels. The brake band was also prone to wearing fairly quickly.

Something to bear in mind with both the 2 and 3(UC) boxes is that the oil pump is driven off the output shaft, and with the engine idling in neutral there is nothing being pumped round the internal lubrication system, so avoid excessively long periods of running the engine out of gear, and if you have to do so then clutch in for a minute or so after no more than half an hour.

Another point to note with regards to the oil pump and lubrication system is that if tied up with the engine stopped and box in neutral in a current or tide strong enough to paddle the prop round, then the oil pump will empty the gearbox sump into the flywheel sump and the box will be running dry for the first few minutes after the next start up.

Thanks for this important info. Looking at the gearbox you'd think it was indestructible. I'll be cringing now every time I go astern.

[Tony Dunkley]

Thanks for this important info. Looking at the gearbox you'd think it was indestructible. I'll be cringing now every time I go astern.

 

There's no need to . . . . these boxes made a loud and distinctive howling/ whining noise when operating astern from the day they left the factory. It's not a sign that they're worn out or about to fail, but all due to the design of the reversing gear train which is all straight cut bevels.

The kind of use that these boxes didn't stand up to at all well was when they were frequently (many times daily) transmitting the 6LX's Heavy Duty Marine Rating of 110 Bhp in astern gear for long enough to bring well over 300 tons to a standstill , . . . . and you're not going to be doing that with yours.

[swift1894]

There's no need to . . . . these boxes made a loud and distinctive howling/ whining noise when operating astern from the day they left the factory. It's not a sign that they're worn out or about to fail, but all due to the design of the reversing gear train which is all straight cut bevels.

The kind of use that these boxes didn't stand up to at all well was when they were frequently (many times daily) transmitting the 6LX's Heavy Duty Marine Rating of 110 Bhp in astern gear for long enough to bring well over 300 tons to a standstill , . . . . and you're not going to be doing that with yours.

Thanks for the reassurance

Having said that, what replacement parts should I look out for, should I ever come across any?

[swift1894]

Btw I can only find a serial number on the reducing gearbox, nothing on the reversing gearbox. Is there one somewhere?

Also what's the recommended use of the grease cup on the reducing box?

Edited March 16, 2015 by swift1894