ZF12 Gearbox - Which way is forward?!

[darbon]

I'm slightly amused by what a basic question this is, and my inability to figure it out!! I've looked at the technical drawings and looked for marks on the box itself, but i can't work out which way the lever should go for Position A (forward) or Position B (reverse)

 

Yes, i DO know which way makes the boat actually go forward or reverse! Currently in my configuration, pulling the lever towards the stern propels the boat forward (opposite to what i'd expected)

 

I'm just trying to work out:

Whether i'm using reverse gear to go forward?

Whether or not a ZF gearbox minds being driven in reverse for long periods? Unfortunately the gear ratio for reverse is not the same as forward.

 

please note, this is a temporary arrangement before i can afford a new matched engine, box and propeller. I just got my current lot on the cheap!

 

D

[RLWP]

Those ZF Hurth gearboxes work by the top of the lever going forwards for forwards, backwards for backwards

 

Does it work properly? I'm asking because the wedging ball has to be going the 'right' way. Do you have to hold it in gear with the lever

 

Richard

[Timleech]

I think some Hurth/ZF boxes are OK running either way, but if you can't find the info on their website then suggest checking with the horse's mouth to be certain?

 

Edit - Presume your engine is normal (modern, vehicle) rotation? Some of their boxes can be modified for opposite engine rotation but they have to be taken apart to do it.

 

Tim

Edited July 10, 2013 by Timleech

[RLWP]

AIUI, there are ZF Hurth boxes in either rotation, but the internals are different

 

Richard

[Timleech]

AIUI, there are ZF Hurth boxes in either rotation, but the internals are different

 

Richard

 

As regards engine rotation, they can be modded to reverse it. I bought a new one for a customer a couple of years ago, the supplier took a standard one off the shelf and stripped it to change it. I don't think any significant parts were needed.

 

Tim

 

Edit - if you look HERE it shows a slightly reduced power rating for the B position, the graphs say both ratings are for continuous power but the general description says A is the 'continuous' position. If worried about it, I would try talking to the makers.

 

Tim

Edited July 10, 2013 by Timleech

[RLWP]

 

As regards engine rotation, they can be modded to reverse it. I bought a new one for a customer a couple of years ago, the supplier took a standard one off the shelf and stripped it to change it. I don't think any significant parts were needed.

 

Tim

 

 

Yes, I remember now. You remove the clutches and change mechanism, then put them back on the shaft the other way around

 

I suspect it was the same supplier who showed me that

 

Richard

[darbon]

Ok thanks. Well it would appear that I am going in reverse then! Will probably do for the mean time, I'm not travelling far. Interesting to know that you can change them around, I'll look into that one.

 

D