Lister LH150 Reversing Box

[paulcatchpole]

It means it's still in forward, 'cos the clutch is stuck, innit

 

Richard

 

Hopefully that rattle left and right doesn't mean your driveplate is knackered...

 

Woss the difference between stuck in forward with the bolt removed (as normal) with the shaft actually stuck and not movable - and stuck in forward with the bolt inserted, with the play and rattle. It looks to be movement within the box, but I guess it could be rocking on some large angular play in the driveplate I guess... If it even has a driveplate?

 

Shouldn't both engagements of forward feel the same?

 

PC

[WotEver]

Shouldn't both engagements of forward feel the same?

Wouldn't have thought so, no. Without bolt, box is in fwd. With bolt, box is in neutral but plate is stuck in fwd. Stiction, stuck, glued, not free to rotate

[RLWP]

 

So Part E is turning inside part D. With the box in neutral, what happens though? I guess that the output shaft should try to drive part D around via the sun and planet gears, but there will be inertia and some drag from the reverse gear friction band. I also guess that Paul isn't strong enough to overcome that lot by only gripping the output shaft

 

Richard

 

It means the cone clutch isn't stuck. That's what it means

 

So, what else is going on?

[Mick_B]

Mine is the manual verssion and sticks in forward all the time. If I forget and go from neutral to reverse I stall the engine. I knock it in and out of reverse very quickly to disengage the cone. Sometimes it takes a couple of tries when not warmed up completely.

I have noticed lately it is begining to free up a little and sometimes comes out of forward itself. Mine had water in the engine, gearbox and reduction box for over 3 years...

[alan_fincher]

At risk of appearing even dumber, but.....

 

I usually can make a crack at understanding sectioned engineering drawings.

 

But when I look at the one in this thread, I am still completely unclear where the gears (those that constitute "reverse") actually are.

 

Some clues please - it might need a version of the diagram with some big arrows on though - sorry to be so dense!

Edited May 4, 2010 by alan_fincher

[paulcatchpole]

<snip>

 

So Part E is turning inside part D. With the box in neutral, what happens though? I guess that the output shaft should try to drive part D around via the sun and planet gears, but there will be inertia and some drag from the reverse gear friction band. I also guess that Paul isn't strong enough to overcome that lot by only gripping the output shaft

 

Richard

 

It means the cone clutch isn't stuck. That's what it means

 

So, what else is going on?

 

Well, anecdotally, from our ST2/LH150 combo, the output shaft will turn gently and slowly when in neutral with the engine running, stoppable by hand or foot on the coupling - so that would be the drag I guess?

 

I've never tried manually engaging neutral on our ST2's box to see how hard it is to turn.

 

On the SR3 in question, when I say I couldn't get neutral, I mean that I had my hand on the output shaft to see, and I couldn't detect a change in speed or my ability to slow it (none) between forward and neutral positions on the selector...

 

In neutral, the end float is present when the box is in the neutral selection position, 'cause you can gently push the shaft in and it'll slowly float out again, while turning...

 

Not sure if that helps anything.

 

So if I've not got a stuck cone (ouch), then what have I got?

 

PC

[WotEver]

It means the cone clutch isn't stuck. That's what it means

I missed something... how do you get to that conclusion, Richard? In fact, why do you say "Part E is turning inside part D"? I thought we'd established that they're not turning independantly because they're stuck together. No?

 

T.

[RLWP]

I missed something... how do you get to that conclusion, Richard? In fact, why do you say "Part E is turning inside part D"? I thought we'd established that they're not turning independantly because they're stuck together. No?

 

T.

 

From watching the video

 

 

Richard

[MoominPapa]

At risk of appearing even dumber, but.....

 

I usually can make a crack at understanding sectioned engineering drawings.

 

But when I look at the one in this thread, I am still completely unclear where the gears (those that constitute "reverse") actually are.

 

Some clues please - it might need a version of the diagram with some big arrows on though - sorry to be so dense!

 

I'm home now and have looked in the manual for my gearbox, which is a "G2", the previous generation to this. However apart from being manual rather than hydraulic and using a multi-plate clutch rather than a cone clutch for ahead, the principle seems to be the same.

 

The drive in reverse goes from the pinion on the input shaft to the pinion on the output shaft, both of which are to the left of the cone clutch. There are two sets of small gears on the spider: each set consist of two gears. One gear is short and meshes only with the input pinion. It also meshes with a long gear next to it. This gear is slightly further out from the axis so it doesn't mesh with the input pinion, being longer, it reaches righwards where it does mesh with the output pinion. In reverse the spider is held still and the input pinion drives the short small gears which drive the long small gears which in turn drive the output pinion. The output pinion has to be slightly bigger than the input pinion so the ratio is just less than 1:1.

 

You can see the short pinion from one of the pairs at the top of the cross-section, and the long pinion from the other pair at the bottom.

 

In forward, the spider is locked to the output shaft which in turns stops the short and long gears from turning. This locks the input pinion too, and the whole assembly turns.

 

In neutral, the spider rotates and stops the gears from transmitting drive.

 

Clear as mud?

 

MP.

[RLWP]

I'm home now and have looked in the manual for my gearbox, which is a "G2", the previous generation to this. However apart from being manual rather than hydraulic and using a multi-plate clutch rather than a cone clutch for ahead, the principle seems to be the same.

 

The drive in reverse goes from the pinion on the input shaft to the pinion on the output shaft, both of which are to the left of the cone clutch. There are two sets of small gears on the spider: each set consist of two gears. One gear is short and meshes only with the input pinion. It also meshes with a long gear next to it. This gear is slightly further out from the axis so it doesn't mesh with the input pinion, being longer, it reaches righwards where it does mesh with the output pinion. In reverse the spider is held still and the input pinion drives the short small gears which drive the long small gears which in turn drive the output pinion. The output pinion has to be slightly bigger than the input pinion so the ratio is just less than 1:1.

 

You can see the short pinion from one of the pairs at the top of the cross-section, and the long pinion from the other pair at the bottom.

 

In forward, the spider is locked to the output shaft which in turns stops the short and long gears from turning. This locks the input pinion too, and the whole assembly turns.

 

In neutral, the spider rotates and stops the gears from transmitting drive.

 

Clear as mud?

 

MP.

 

Spot on. Apart from the different diameter gears, that's what I worked it out to be.

 

Richard

 

Thanks for that

[Guest User]

I'm at the check-everything-all-over-again-even-if-it's-not-relevant stage .... is the brake band correctly adjusted ?

[alan_fincher]

Clear as mud?

 

MP.

Sorry, no!

 

Must be me I guess, but I'm not convinced I can identify for absolute certainty any of the (I think!) 6 gears in total you are talking of.

 

I'd love to understand, but I suspect without a diagram with the pinions/cogs/whatever actually labelled, I'm not going to get there!

 

In my ("differential-like") Parsons box, all the gears were bevel gears, but I'm guessing none of these are ?

 

Thanks for trying, anyway!

[MoominPapa]

Sorry, no!

 

Must be me I guess, but I'm not convinced I can identify for absolute certainty any of the (I think!) 6 gears in total you are talking of.

 

I'd love to understand, but I suspect without a diagram with the pinions/cogs/whatever actually labelled, I'm not going to get there!

 

In my ("differential-like") Parsons box, all the gears were bevel gears, but I'm guessing none of these are ?

 

Thanks for trying, anyway!

It would help if I could get my scanner going and post an exploded diagram. Absent that, here goes.

 

The input shaft is on the left and the output on the right: find the bush in the middle where the output shaft runs inside a hole in the input shaft. The pinion on the input shaft is right at the end, around the hole with the bush, the pinion on the output shaft is also at the end, just to the right is the pinion on the output shaft.

 

You can't see all the small gears, two of them are out of the plane of the cross-section. What you can see is the short gear from one pair above the input shaft and meshed with it. You can also see the long gear from the other pair, below the shaft. Note that this is slightly further away and doesn't mesh with the input pinion but it does mesh with the output pinion.

 

I hope Lister had patents on this stuff!

 

MP.

 

Edited to add: I photographed the diagrams and put them here and here. Warning, big images behind a slow internet connection, don't click these unless you really want to wait and see them.

Edited May 4, 2010 by MoominPapa

[alan_fincher]

Ah!

 

Thanks - I think I am finally there!

 

So I guess it does still class as "epicyclic", but not with gears arranged as many of us instinctively think.

 

In the type I was talking about 1:1 was a given, I think. I finally understand why it is not here.

 

I can't immediately see the advantage of this over the type I had, which had only 4 bevel gears in total, and seemed less complex.

 

Except I imagine the engineers will tell me that bevel gears are a less satisfactory piece of design than "unbevelled" gears. (Certainly a Parsons box always whines heavily in reverse - what gave the Petter re-engined BW Town and Star boats such a distinctive sound when working throughh locks, I'd say).

[RLWP]

Equally, my PRM box with multiple shafts, fewer gears and two plate clutches makes both other boxes look archaic. I can't see the advantage of either of those types, but then, it's the devil I know, isn't it Alan.

 

Richard

 

Parts list for the curious

Edited May 4, 2010 by RLWP

[MoominPapa]

I can't immediately see the advantage of this over the type I had, which had only 4 bevel gears in total, and seemed less complex.

 

Except I imagine the engineers will tell me that bevel gears are a less satisfactory piece of design than "unbevelled" gears. (Certainly a Parsons box always whines heavily in reverse - what gave the Petter re-engined BW Town and Star boats such a distinctive sound when working throughh locks, I'd say).

The Lister type whines too (certainly the older ones) you can see why when the reverse drive goes through all of those straight-cut gears.

 

I guess that the advantage of the Lister scheme over bevel gears is the lack of sliding tooth contact and therefore the need for "EP" oil. The original ones like I have share oil with the engine.

 

MP.

[Timleech]

Ah!

 

Thanks - I think I am finally there!

 

So I guess it does still class as "epicyclic", but not with gears arranged as many of us instinctively think.

 

In the type I was talking about 1:1 was a given, I think. I finally understand why it is not here.

 

I can't immediately see the advantage of this over the type I had, which had only 4 bevel gears in total, and seemed less complex.

 

Except I imagine the engineers will tell me that bevel gears are a less satisfactory piece of design than "unbevelled" gears. (Certainly a Parsons box always whines heavily in reverse - what gave the Petter re-engined BW Town and Star boats such a distinctive sound when working throughh locks, I'd say).

 

Any straight-cut (rather than Helical) gears will tend to be noisy, the Lister Blackstone boxes can be horrible in astern if the gears are less than perfect. We had a Self-Changing Gears hydraulic box on our Gardner 4LW, that had small planetary reverse gears working on a bigger central pinion than the Lister boxes, which often led onlookers to ask "is that engine turbocharged?"

 

Tim

[MoominPapa]

Equally, my PRM box with multiple shafts, fewer gears and two plate clutches makes both other boxes look archaic. I can't see the advantage of either of those types, but then, it's the devil I know, isn't it Alan.

 

Richard

 

Parts list for the curious

 

The Lister box has far fewer bearings: the PRM box has three shafts, two bearings each, all rotating all the time. The Lister box has one shaft, which is supported by the engine main bearing at one end, and one other bearing for a 1:1 box. If there's a reduction box there are still only three bearings in motion and contributing friction when in forward.

 

Since modern designs don't look like the Lister, I guess that it's a failed design now, but it does have some advantages.

 

MP.

[Timleech]

Equally, my PRM box with multiple shafts, fewer gears and two plate clutches makes both other boxes look archaic. I can't see the advantage of either of those types, but then, it's the devil I know, isn't it Alan.

 

Richard

 

Parts list for the curious

 

I think the basis of the PRM design was probably originated by TwinDisc in the USA, also used by Kelvins for their hydraulic boxes and probably others too. No idea when the first ones were produced though.

 

Tim

[RLWP]

The Lister box has far fewer bearings: the PRM box has three shafts, two bearings each, all rotating all the time. The Lister box has one shaft, which is supported by the engine main bearing at one end, and one other bearing for a 1:1 box. If there's a reduction box there are still only three bearings in motion and contributing friction when in forward.

 

Since modern designs don't look like the Lister, I guess that it's a failed design now, but it does have some advantages.

 

MP.

 

That's the disadvantage of me talking in riddles...

 

I can't see any particular advantage or disadvantage of any of these boxes. They all work, they all drive boats, they all brought a profit to the companies that sold them. For me trying to identify one or other as better or worse, having an advantage or disadvantage is really pointless speculation. To me, the best is the PRM 260. It's the best because it's the one I have and it works. Having any other would mean spending money to get it and I don't want to do that. So on my criteria - how much will it cost me - the particular PRM 260 in my boat is by far the best.

 

I'm not sure what criteria you would use to decide if a Parsons box was "better" or "worse" than a Lister box, or a PRM box either

 

Richard

[springy]

Hi Paul

 

This threads grown a bit since last night - its just taken me half an hour to

catch up!

 

I've also gone back to your video & come up with another question. First am

I correct in thinking that the video was made with "Bolt B replacing Bolt A" to

overcome the pressure of the spring pack i.e. hold the box in neutral ? If so

then the slight rotation play could indicate one of two things - which one

is not clear in the video, but you may be able to see the difference in situ.

 

When you rotate the shaft :-

Either item E moves a small amount but item D does not - if so the friction

material has probably broken up and is jamming,

Or items E and D are still locked together and the movement is the backlash

in the splines/geartrain.

you may be able to tell the difference if you look carefully but in the video the

reverse brake band effectively obscures the two.

 

If the friction material has broken up then you have no option but to strip the

box, if the E and D are still stuck together then I would be tempted to see if a

point of leverage could be found to use a large screwdriver and try carefully to

persuade item E to move backwards away from item D, with the bolt still in

position to overcome the spring pack of course. Because the forward band is a

Cone section they are more prone to just sticking.

 

springy

[paulcatchpole]

Hi Paul

 

This threads grown a bit since last night - its just taken me half an hour to

catch up!

 

Aye, all good discussion fun! Ta for taking the time to catch up with it...

 

I've also gone back to your video & come up with another question. First am

I correct in thinking that the video was made with "Bolt B replacing Bolt A" to

overcome the pressure of the spring pack i.e. hold the box in neutral ? If so

then the slight rotation play could indicate one of two things - which one

is not clear in the video, but you may be able to see the difference in situ.

 

Yes, the video was taken whilst the magic bolt was in place... Without the bolt, the output shaft is locked solid, at least to hand pressure...

 

When you rotate the shaft :-

Either item E moves a small amount but item D does not - if so the friction

material has probably broken up and is jamming,

Or items E and D are still locked together and the movement is the backlash

in the splines/geartrain.

you may be able to tell the difference if you look carefully but in the video the

reverse brake band effectively obscures the two.

 

If the friction material has broken up then you have no option but to strip the

box, if the E and D are still stuck together then I would be tempted to see if a

point of leverage could be found to use a large screwdriver and try carefully to

persuade item E to move backwards away from item D, with the bolt still in

position to overcome the spring pack of course. Because the forward band is a

Cone section they are more prone to just sticking.

 

springy

 

It'll have to wait to the weekend for me to have the box in front of me to try it again to see what's happening. Nothing in the box looks really broken up in a physical sense, but you never know. I'm tempted to say that E and D are moving together, and the play is on the splined shaft through the middle, which also would explain the end float that appears...

 

Is the another explanation for the apparent end float, separate from the play?

 

Cheers!

 

PC

[Timleech]

Aye, all good discussion fun! Ta for taking the time to catch up with it...

 

 

 

Yes, the video was taken whilst the magic bolt was in place... Without the bolt, the output shaft is locked solid, at least to hand pressure...

 

 

 

It'll have to wait to the weekend for me to have the box in front of me to try it again to see what's happening. Nothing in the box looks really broken up in a physical sense, but you never know. I'm tempted to say that E and D are moving together, and the play is on the splined shaft through the middle, which also would explain the end float that appears...

 

Is the another explanation for the apparent end float, separate from the play?

 

Cheers!

 

PC

 

Try putting the reduction pinion back, along with the bearing inner and nut.

 

Tim

[paulcatchpole]

Try putting the reduction pinion back, along with the bearing inner and nut.

 

Tim

 

I will do, next week, when I can make it a priority. We're there most of the week getting some major progress made, with luck.

 

I've got the reduction in hundreds of pieces at the moment, awaiting the arrival of the bearings and other stuff. I'd like to reassemble it with those bits, then I can stick it back on to see if it makes a difference.

 

As a thought, though, didn't these run without the reduction quite happily? Mind you, guess the float would be controlled either way, by the prop shaft?

 

PC

[Timleech]

As a thought, though, didn't these run without the reduction quite happily? Mind you, guess the float would be controlled either way, by the prop shaft?

 

PC

 

They had a half-coupling fixed to the main shaft, in muh the same way the the reduction pinion is. Without that, the shaft can move forwards until it meets something else inside the box.

 

Tim