MD2030D to MS2B Gearbox

[BigStu]

Hi all

I posted yesterday about my engine and whether the seawater inlet was large enough. The engine is a MD2030D mated to a MS2B Gearbox. Does anyone else have this set up?

Mine was installed a number of years ago and never commissioned, then I purchased the boat and the engine has been commissioned, running- but not yet used in water as the boat has not gone in yet.

I'm baffled by the seawater cooling circuit. the pipes should be 19mm (as per post yesterday) all the way around the system, however the MS2B Gearbox has a water cooled bearing that uses 13mm inlet/outlet. The setup currently has a 13mm seacock inlet then 13mm hose through the strainer, through the bearing in the gearbox then steps up to 19mm to the pump, through the engine and out of the exhaust.

I've established now that it should be 19mm all the way around- but what do you do about the gearbox bearing that is 13mm as that constitutes a blockage in reality?? You can't really step it down a size just for that and step back up after the bearing as that will affect the efficiency of the circuit and potentially cause overheating.

it's making me think this is not the right gearbox to go with this engine- but does anyone use this combination??

 

[VicS]

Early versions of the engine were fitted to an MS2 type gear box. Later versions to an MS10 type. The later were do not appear to have been water cooled

From a 1998 manual:

 

[BigStu]

What I don't understand on mine is why the pipes leading to the pump and beyond are 19mm, but the pipes to from the gearbox are 13mm. There is a bizarre home mad 'step up' copper pipe to go from 13mm to 19mm (see photo). As a forum member said yesterday it seems like a bodge- but does anyone else have this?? I'm guessing a may have a gearbox that was originally on a smaller engine etc as this cannot be a recommended way to do it.

 

[BigStu]

I should have said the inlet seacock is 13mm but the pipes are 16mm as you can see in the photo. Still- 16mm is too small for this engine as the pipes too and from the pump are 19mm.

 

[tillergirl]

How about a 2030B?

On installation

DSC01875 by Roger Gaspar, on Flickr

DSC01877 by Roger Gaspar, on Flickr

After 25 years use. I think it was 19mm from strainer to heat exchanger. The bottom of the strainer (made in 1965 for a BMC 1500) was only a 15mm hole in the hull.

76 by Roger Gaspar, on Flickr

The suck of the pump was terrific - got a jelly fish in the strainer once. There was ample water through the system. Occasionally I did get partial blocking when weed partially excluded raw water. the symptom was steam as well as water through the exhaust. A simple stopping of the engine while still moving washed the weed away and on restart water flow resumed normality and steam stopped.

 

[BigStu]

How about a 2030B?

On installation

DSC01875 by Roger Gaspar, on Flickr

DSC01877 by Roger Gaspar, on Flickr

After 25 years use. I think it was 19mm from strainer to heat exchanger. The bottom of the strainer (made in 1965 for a BMC 1500) was only a 15mm hole in the hull.

76 by Roger Gaspar, on Flickr

The suck of the pump was terrific - got a jelly fish in the strainer once. There was ample water through the system. Occasionally I did get partial blocking when weed partially excluded raw water. the symptom was steam as well as water through the exhaust. A simple stopping of the engine while still moving washed the weed away and on restart water flow resumed normality and steam stopped.

That's interesting! So what size pipes go to the two copper pipes in/out of the gearbox in the middle photo....?

 

[tillergirl]

On memory (1995), it was all the same hose, same as hose from water pump to heat exchanger. I guess it was 19mm - certainly bigger than 15mm and smaller than 25mm. Unfortuantely I do not have the installation drawings any more. I am certain I only had one size from strainer to heat exchanger including via the syphon break. The white pipe is water feeding (cooling and lubricating the stern gland). I am pretty certain 16mm wouldn't have gone on the gearbox cooler.

Of course this is the 2030B. Do you have different pipes on the gearbox cooler reducing the pipes?

 

[BigStu]

Yes- essentially the pipes on the gearbox are smaller So it reduces the flow until after the gearbox when it steps up to 19mm. Mechanics have said it would ‘probably be ok’ unless running at full tilt….. but that is obviously not ideal and it’s never been tested as not commissioned in the water under load. Trouble is when you need an engine most…. It often means full power! I can’t find any info on this in terms of an install….

 

[tillergirl]

I am surprised that the pipe on the gearbox are smaller. The pipe is a bespoke fitting onto the gearbox so what you have must be a standard Volvo fitting. Have you a photo of gearbox? (I tried to find an installation or parts diagram on the web but unsuccessfully)

 

[BigStu]

I am surprised that the pipe on the gearbox are smaller. The pipe is a bespoke fitting onto the gearbox so what you have must be a standard Volvo fitting. Have you a photo of gearbox? (I tried to find an installation or parts diagram on the web but unsuccessfully)

Not a lot online! I'm baffled by it. The seacock inlet has an internal diameter of 11mm and the gear box pipes are about 13mm internal diameter- by the time you get to the pump the internal diameter is 16mm! If anything the seacock needs changing to 3/4 inch but all these different size pipe bores seem dodgy to me! The gearbox pipes inlet and outlet look smaller to me than on most…see photo

 

[scottie]

The gear box is used with engines of various HP up to 48 or perhaps 60 so the pipes are actually slightly misleading

 

[tillergirl]

Umm, does look a bit of a mystery. Point 1: I would reckon 11mm internal for the seacock inlet is a little small. I had had a BMC 1500 and it had what I remember as about 1/2" (certainly wasn't metric - made by the Southend Engineering Co Ltd). Point 2, the gearbox 'tail' is different to the 2030B original. The 2030B pipe was stepped down to 19mm and of course the end could be cut off to fit 25mm pipe. I was told the 19mm would be fine (and it certainly has been). The gearbox tails and pump tails were all matched and I would be amazed it a 2030D was different.

Can I suggest you ring Volspec and speak to them. It is a few years since but I have always found them helpful.

 

[Bilgediver]

Hi all

it's making me think this is not the right gearbox to go with this engine- but does anyone use this combination??

I would speak to Beta about this. I think the problem is that the gearbox sized plumbing is a hangover from when these gearboxes were used with engines fitted with direct cooling. These engines had a much lower flow rate than an engine using a heat exchanger and yes you will be strangling the flow to the heat exchanger. I am sure Beta used to require the sea inlet to be enlarged for this very reason when replacing old Volvo engines so this seems to be a contradiction. It may require a bypass pipe to be fitted to get optimum flow rates to the heat exchanger . The bypass would need a valve in it to adjust so as to get the required flow through the gearbox.

Well done for spotting this.