Parsons Reverse Gear type DA

[Les Mathieson]

Dear all, I am new to this forum. my name is Les Mathieson & I live on the Gippsland Lakes at Paynesville in Australia. I joined to forum to find out some info on a Parsons Reverse Gear in my boat. having said that my wife & I have holidayed on canal boats in France & dream of doing the same in a narrow boat in the UK, more of that later.

I have a Parsons Reverse Gear coupled to a Perkins 4107 in a Halvorsen 25 (ft) Cruiser. the boat has nearly finished a major overhaul. I have found little info on the parsons Reverse Gear, mine operates OK, but the shaft still spins when in neutral. I must have missed something in this post because I cannot find how to adjust the neutral to stop the shaft turning. Any ideas please?

Also there is talk of the unit being able to 'lock' in reverse, similar to how the units locks in forward. in mine you simply have to hold it in reverse position, is this what is meant to happen?

I would love a copy of an operating manual if available.

I tried to include photo f my boat, but I cannot seem to do this, failed again.

cheers & thanks

Les Mathieson

[Timleech]

Dragging ahead while in neutral is a common issue with Parsons boxes.

They have multiplate clutches for Ahead operation, and the inner plates sit on a large diameter shallow 'spline'. What can happen over years of use is that the spline on the (thin) plates wears notches into the male spline in the ahead position on the core (usually integral with a large bevel gear). The plates then tend to sit in these notches rather than releasing freely into the neutral position.

The proper cure is a new central core/gear and clutch plates, but that may well not be an option now. A good engineering shop might be able to build up the splines and machine them back, but it would be a delicate operation to avoid distortion etc., I've never tried it.

 

Of course yours might just be an adjustment issue. This 'notching' is I think particularly an issue with one- and two- cylinder engines with their large cyclical speed variations.

 

HTH

Tim

[RLWP]

Adding another aspect to this, the movement between 'locked' and 'free' on the in the forward plate clutch isn't very much, so the gaps between the plates in neutral is pretty small. In addition the oil is quite viscous, and the plates have a large area.

 

All this adds up to quite a lot of drag just from the oil between the plates. I have an old DA box here that I can barely turn by hand in neutral because of the gloopy old oil

 

So, if it is only idling, and you can put up with it - it's an old gearbox. If it ain't broke, don't fix it

 

Richard

[Les Mathieson]

Thanks Tim & Richard,

We will continue to work on the old girl & change the oil in the box, and put up with the slight inconvenience.

Les

[immarkani]

Hi,

 

I am trying to uncouple a Parsons Type Gearbox from a Rolls Royce C8TFLM (gearbox identified as RRD8 - however I wish I could confirm this if somehow I could attach a picture, which I am currently not allowed to), however after moving 5 - 8 mm, everything jammed - jacks getting really hard and stopped the process?

 

My question is, because I have no drawings or breakdown of the components , has anyone have experience of separating the engine from the gear box and if so, does the gear box come off the bell housing leaving the bell housing attached to the engine or does the bell housing come off complete with the gearbox attached?

 

Thanks in anticipation

Mark

[RLWP]

To post pictures, you need to host them elsewhere, like Photobucket, and link them to here

 

I would expect the flywheel housing to come off with the gearbox

 

Some pictures would help though

 

Richard

[Timleech]

You could try asking Parsons Mathway?

I believe they have changed hands and are now more active than they had been for some time.

 

Tim

[RLWP]

You could try asking Parsons Mathway?

I believe they have changed hands and are now more active than they had been for some time.

 

Tim

This is true. They are based local to me , I know they are getting clutch plates cut

 

Richard

[jake_crew]

Often the guts of a marine gearbox are attached to the engine drive flange, so will need unbolting through an access plate on the box.

 

IE its NOT like an old RWD car where the splined gearbox shaft just pushes into the clutch plate.

Edited June 30, 2014 by jake_crew

[immarkani]

Hi all,

 

Thanks for all your replies. Took your advice Richard and it seems to be working.

 

http://i1274.photobucket.com/albums/y431/Mark_Azzopardi/2014-06-30113215_zps33f4cbfd.jpg

 

http://i1274.photobucket.com/albums/y431/Mark_Azzopardi/2014-06-30113226_zps1b5b83da.jpg

 

The images show the lateral movement thus far. Maybe the gearboxes could be identified...?

 

What we are thinking to do is to support the gearbox, just to take the weight and if possible loosen the bolts of the dumper from the inspection plates.

 

Then attach the aft side of the bell housing back to the gearbox and uncouple from the engine.

 

We are sliding the engine aside instead of the shafts out as the engines need to come out anyway.

 

Do you have any idea whether this type of gearbox has splines on the shaft and whether it has some sort of block flex coupling?

 

Thanks,

Mark

[RLWP]

What can you see through the access panel on the flywheel housing - the one on top held on with four bolts?

 

Richard

[immarkani]

Hi Richard,

 

So we have finally managed by uncoupling the engines from the coupling bolts (10) on the flywheels accessed from the hand holes on the two sides of the bell housing – concealed by the jacks in my previous uploaded photo.

 

Below I'm attaching more photos of the inside. One question does these 10 bolts need to be torqued? Maybe someone has some literature about this gearbox to indicate this.

 

http://i1274.photobucket.com/albums/y431/Mark_Azzopardi/2014-07-02081111_zpsc70929d1.jpg

 

http://i1274.photobucket.com/albums/y431/Mark_Azzopardi/2014-07-02075940_zps1cb27a5c.jpg

 

http://i1274.photobucket.com/albums/y431/Mark_Azzopardi/2014-07-02092400_zpsca2a21bb.jpg

 

Thanks,

Mark

[Timleech]

Hi Richard,

 

So we have finally managed by uncoupling the engines from the coupling bolts (10) on the flywheels accessed from the hand holes on the two sides of the bell housing – concealed by the jacks in my previous uploaded photo.

 

Below I'm attaching more photos of the inside. One question does these 10 bolts need to be torqued? Maybe someone has some literature about this gearbox to indicate this.

 

 

 

Thanks,

Mark

Have you tried asking Parsons Mathway yet?

 

Tim

[David Mack]

I don't know what type of Parsons gearbox this is, but at 36" long its enormous!

 

http://www.ebay.co.uk/itm/201118599657