Lister blackstone and similar gear linkage.

[BudgetBus]

Could you fine fellows possibly post some images of your linkage set up for mid engine rooms. I’m tired of my cobbled together contraption causing issues. 

 

thanks 

[frangar]

3 hours ago, BudgetBus said:

Could you fine fellows possibly post some images of your linkage set up for mid engine rooms. I’m tired of my cobbled together contraption causing issues. 

 

thanks 

I’ll try and take some tonight or tomorrow of my set up. Send me a DM if I forget! 

[BudgetBus]

On 13/01/2022 at 09:33, frangar said:

I’ll try and take some tonight or tomorrow of my set up. Send me a DM if I forget! 

Thanks. Did you remember?

[frangar]

6 minutes ago, BudgetBus said:

Thanks. Did you remember?

Clearly not….hang on!!

[frangar]

Here you go!….I apologise for the mess! 

The frame at the top is bolted to the gear rod from the stern…the joint between the black frame and the brass rod then pivots and slides on the brass rod. Works well with a reasonable throw from the stern. 

[BudgetBus]

8 hours ago, frangar said:

Here you go!….I apologise for the mess! 

The frame at the top is bolted to the gear rod from the stern…the joint between the black frame and the brass rod then pivots and slides on the brass rod. Works well with a reasonable throw from the stern. 

That looks like a set up that I could incorporate into my existing change. I currently have about 4 ft or travel and in the past the flex in the upright has caused it to pop out of location. I was contemplating lowering the shaft to the lovel of my lower cupboards in me rear cabin and having a foot operated change. But I like yours. Thanks for taking the pictures. 

[agg221]

There's quite an elegant solution I saw on The King. I don't think I have any pictures, but the principle is to use a vertical rotating shaft in the engine room, mounted to the ceiling and the floor (or engine bed). The shaft has a lever sticking out sideways which links to the gear rod at the top and the gearbox rod at the bottom, using a crank as necessary. The relative length of the top lever and the bottom lever (from the vertical shaft to the pivot point) can be varied to achieve a ratio between them, ie you can extend or reduce the throw on the gear rod as necessary. What I like about it is that because the vertical rod is under neutral stress, it is not prone to drifting forwards or backwards. A friend with the same issue of overly long travel on the gear rod on his JP2 is looking at changing to the vertical rod set-up to reduce the throw to something more practical. If this description does not make sense and it's an interesting enough approach that you would like pictures, let me know and I can request some.

Alec

[BudgetBus]

1 minute ago, agg221 said:

There's quite an elegant solution I saw on The King. I don't think I have any pictures, but the principle is to use a vertical rotating shaft in the engine room, mounted to the ceiling and the floor (or engine bed). The shaft has a lever sticking out sideways which links to the gear rod at the top and the gearbox rod at the bottom, using a crank as necessary. The relative length of the top lever and the bottom lever (from the vertical shaft to the pivot point) can be varied to achieve a ratio between them, ie you can extend or reduce the throw on the gear rod as necessary. What I like about it is that because the vertical rod is under neutral stress, it is not prone to drifting forwards or backwards. A friend with the same issue of overly long travel on the gear rod on his JP2 is looking at changing to the vertical rod set-up to reduce the throw to something more practical. If this description does not make sense and it's an interesting enough approach that you would like pictures, let me know and I can request some.

Alec

That would be helpful. 

[David Mack]

Previous thread on the subject, although a number of the pictures seem to be missing.

And another forum member's elegant solution to the problem.

 

[BudgetBus]

3 hours ago, David Mack said:

Previous thread on the subject, although a number of the pictures seem to be missing.

And another forum member's elegant solution to the problem.

 

Very useful thanks. 

[agg221]

On 15/01/2022 at 19:54, BudgetBus said:

That would be helpful. 

Pictures of the gear linkage on The King as requested. It's a Gardner 2LW but the principle translates easily into the Blackstone box.

 

The first picture shows the upper part of the linkage. The gear rod from the steering position is ringed in pink. The bar in light blue determines the direction of rotation of the vertical rod, by which side of the rod it lies.

 

The travel of the gear rod between forward and reverse is governed by the total arc the lever out of the gearbox travels through, the vertical position at which the connection to that lever is made (higher up means more travel, lower down shorter travel) and the ratio of the lengths of the upper and lower bars ringed in green (first and second picture respectively). On this particular set-up, the mounting to the lever is as close in as possible, minimising travel to around 6". The ratio of the two bars is around 2:1 reduction, so the gear lever only travels around 3", which is less than I would want if it was mine as it's a little too sensitive to comfortably pull it from ahead to neutral and stop without going into reverse. This could be increased either by increasing the length of the gear lever or changing the ratio between the bars. My own gear change rod does not use this mechanism (yet) but has total travel of around 8", which seems around ideal as neutral to reverse is possible standing in the hatches, full ahead is easy to reach and it is not too fine an adjustment between the positions.

 

Alec

[BudgetBus]

7 hours ago, agg221 said:

Pictures of the gear linkage on The King as requested. It's a Gardner 2LW but the principle translates easily into the Blackstone box.

 

The first picture shows the upper part of the linkage. The gear rod from the steering position is ringed in pink. The bar in light blue determines the direction of rotation of the vertical rod, by which side of the rod it lies.

 

The travel of the gear rod between forward and reverse is governed by the total arc the lever out of the gearbox travels through, the vertical position at which the connection to that lever is made (higher up means more travel, lower down shorter travel) and the ratio of the lengths of the upper and lower bars ringed in green (first and second picture respectively). On this particular set-up, the mounting to the lever is as close in as possible, minimising travel to around 6". The ratio of the two bars is around 2:1 reduction, so the gear lever only travels around 3", which is less than I would want if it was mine as it's a little too sensitive to comfortably pull it from ahead to neutral and stop without going into reverse. This could be increased either by increasing the length of the gear lever or changing the ratio between the bars. My own gear change rod does not use this mechanism (yet) but has total travel of around 8", which seems around ideal as neutral to reverse is possible standing in the hatches, full ahead is easy to reach and it is not too fine an adjustment between the positions.

 

Alec

Thank you, it looks like a pretty simple solution.