Gearbox identification

[Jeremy G]

 

I have already asked this on the engine forum but still not sure.

 

Can anyone help me identify this gearbox please as I have a problem? This is on a 2VSH.

 

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[Tracy D'arth]

Wild guess its a Parsons. Ruston liked them.

[magnetman]

.

 

Edited as realised the oval brass plate refers to the engine. 

Edited August 15, 2023 by magnetman

[Derek R.]

Looks more like an early Blackstone from images on't web.

 

[David Mack]

Doesn't look like any I've seen. Since it has a Ruston Hornsby plate on it, could it possibly be one RH made themselves for their marine engines?

In any event it is almost certainly obsolete with no spares available, so you need someone with the ability to diagnose the problem and either source alternative parts or make something from scratch. Try contacting Primrose Engineering (@RLWP) or Marine Power Services ( @steamraiser2).

[James Owen]

It's a Ruston's version of the 3G Blackstone box, dissimilar casting/housing but near identical internals.

They're straight forward and easy to work on although the OP doesn't mention what the "problem" is...

[Tony Brooks]

9 minutes ago, James Owen said:

It's a Ruston's version of the 3G Blackstone box, dissimilar casting/housing but near identical internals.

They're straight forward and easy to work on although the OP doesn't mention what the "problem" is...

 

He did say it is getting noisy but has not elaborated on it, or confirmed the boat is going forwards when the box is in ahead.

 

If it is going forward when the box is in ahead, then the noise has to be something in the reduction box or worn output bearings. The rest of the box  spins as a large lump.

[Jeremy G]

Thanks for replies.  The gearbox has always been a bit noisy in reverse but has now noisy in forward. Looking from the stern the flywheel is at the front of the engine and runs anti clockwise the prop is right handed. Photo attached

[Tony Brooks]

15 minutes ago, Jeremy G said:

Thanks for replies.  The gearbox has always been a bit noisy in reverse but has now noisy in forward. Looking from the stern the flywheel is at the front of the engine and runs anti clockwise the prop is right handed. Photo attached

 

 

The reduction box reverses the direction of rotation, so if the flywheel turns anti-clockwise looking from the back of the engine, the shaft will rotate clock wise. It looks as if the prop is correctly handed. So if it is noisy in ahead, it must be the reduction box gear teeth or one or more out bearings. The noise of the spinning sun and planet gears when in reverse probably drowns out the noise that you are interseted in.

[James Owen]

5 hours ago, Jeremy G said:

Thanks for replies.  The gearbox has always been a bit noisy in reverse but has now noisy in forward. Looking from the stern the flywheel is at the front of the engine and runs anti clockwise the prop is right handed. Photo attached

A noisy ahead gear will, as Tony says, be failing/worn reduction gears and I can probably hazard a guess as to the reason why.

As mentioned, they are straight forward to repair and most parts are either obtainable or makeable. The only part I had to make on the last one I rebuilt was the main shaft itself but that box had really gone awry 😀

[Tony Brooks]

I don't know the box in detail, but I would be concerned about the apparently polished face on the large brass hexagon nut that is at the back of the gearbox, around the output shaft and up against the bearing.

 

@James Owen what do you think, it is on one of the early photos, but it might be in the other thread the OP started.

[magnetman]

This? 

 

 

ETA no I see you mean the nut at the other end. Image removed. 

 

This one

 

Is there some metal to metal contact there with a grinding effect?

Edited August 17, 2023 by magnetman

[Tony Brooks]

3 minutes ago, magnetman said:

This? 

 

 

No that is, I think, the adjuster for the reverse brake band.

 

It is on the left of the photo where the shaft goes through the casing at the back. I think that the "selector" (for the want of a better word) may be rubbing on it when reverse is engaged. To the left of the end of the tail on your arrow.

[magnetman]

I edited my post. 

[Tony Brooks]

Yes, that is the part that looks polished as if something may have been rubbing on it. However, as I don't have nay experience of these particular boxes, it might be normal, hence my asking for James's opinion.

[Jeremy G]

Thank you for all your comments, nice to confirm that it’s a Lister box and spares available, will be back on the boat next week and will have a closer look and make more sense of it.

[alan_fincher]

3 minutes ago, Jeremy G said:

Thank you for all your comments, nice to confirm that it’s a Lister box and spares available, will be back on the boat next week and will have a closer look and make more sense of it.

I'm not sure I think that is the answer being given.

 

I think it is being descried as a Ruston box, internally very similar to a Lister Blackstone 3G, (but not actually a Lister box).

 

Whether internal parts from one can be used for replacements in the other has not so far been stated.

 

Even with very common Lister Blackstone boxes I'm not convinced spares are always commonly available.  Both my Blackstone boxes have at times relied on second hand part to effect a repair.

[James Owen]

23 minutes ago, alan_fincher said:

I'm not sure I think that is the answer being given.

 

I think it is being descried as a Ruston box, internally very similar to a Lister Blackstone 3G, (but not actually a Lister box).

 

Whether internal parts from one can be used for replacements in the other has not so far been stated.

 

Even with very common Lister Blackstone boxes I'm not convinced spares are always commonly available.  Both my Blackstone boxes have at times relied on second hand part to effect a repair.

That's because you ask the wrong people 😉