MD2020 Raw water pump

[Farrell]

Hi Guys
Advise please I'm looking to change /upgrade the water pump on a Volvo MD2020 and would like to go larger has anyone else done this.
Engine overheats when working hard
I've changed the impeller all looks good seals and wear wise in the pump (thermostat has been changed) just so engine ran but un-tested when working really hard. (3500 Engine hours) but think we could do with more flow. I have and extra water inlet as well as the sail drive intake.
Engine runs perfect apart from this head gasket all good.

Thank you

 

[geem]

Hi Guys
Advise please I'm looking to change /upgrade the water pump on a Volvo MD2020 and would like to go larger has anyone else done this.
Engine overheats when working hard
I've changed the impeller all looks good seals and wear wise in the pump (thermostat has been changed) (3500 Engine hours) but think we could do with more flow. I have and extra water inlet as well as the sail drive intake.

Thank you

Have you cleaned the heat exchanger?
There should be no reason to upgrade the pump

 

[TSB240]

My experience of an MD 2000 was overheating when working hard is
either as result of a blockage in the injection of s3a water post heat exchanger into the exhaust elbow
Or a blockage in the closed circuit water circulating through the heat exchanger.

I would test as follows.
Do you have a good stream of flow of water out of the exhaust?

If not you likely have a blocked exhaust elbow injection point or a less common blocked heat exchanger from a broken up impeller.

If good flow when your engine alarms try putting your hand in the stream of water from the exhaust.

If it is relatively cool ie you can get your hand in it without scalding then the problem is in the closed circuit water flow and a lack of heat exchange.

The flow can be restricted if your antifreeze has not been changed every two years which will cause internal engine waterway corrosion.

Restrictions can be caused by either blocked thermostat,collapsed hoses to and from circulation pump, blockage of the aluminium spigot on the cooling water manifold exit, or very uncommon failure of the engine circulation water pump.

Steve

 

[Tranona]

Hi Guys
Advise please I'm looking to change /upgrade the water pump on a Volvo MD2020 and would like to go larger has anyone else done this.
Engine overheats when working hard
I've changed the impeller all looks good seals and wear wise in the pump (thermostat has been changed) just so engine ran but un-tested when working really hard. (3500 Engine hours) but think we could do with more flow. I have and extra water inlet as well as the sail drive intake.
Engine runs perfect apart from this head gasket all good.

Thank you

Unlikely that it is the capacity of the seawater pump that is the problem. The same capacity pump s fitted to the larger engines in the range and has ample capacity. First thing to do is check the cover plate for wear as well as change the impeller. However as already suggested clean the heat exchanger and remove for inspection the exhaust elbow, If the latter has not been changed then it will almost certainly be blocked and restricting flow of water.

 

[Farrell]

Have you cleaned the heat exchanger?
There should be no reason to upgrade the pump

Heat exchanger cleaned wasn't dirty thanks for reply

 

[Farrell]

My experience of an MD 2000 was overheating when working hard is
either as result of a blockage in the injection of s3a water post heat exchanger into the exhaust elbow
Or a blockage in the closed circuit water circulating through the heat exchanger.

I would test as follows.
Do you have a good stream of flow of water out of the exhaust?

If not you likely have a blocked exhaust elbow injection point or a less common blocked heat exchanger from a broken up impeller.

If good flow when your engine alarms try putting your hand in the stream of water from the exhaust.

If it is relatively cool ie you can get your hand in it without scalding then the problem is in the closed circuit water flow and a lack of heat exchange.

The flow can be restricted if your antifreeze has not been changed every two years which will cause internal engine waterway corrosion.

Restrictions can be caused by either blocked thermostat,collapsed hoses to and from circulation pump, blockage of the aluminium spigot on the cooling water manifold exit, or very uncommon failure of the engine circulation water pump.

Steve

Thanks Steve for reply ill check for blockages at the exhaust elbow.
Exhaust water is warm but not hot.
Seems to be good circulation to calorifier on fresh water system.
No real wear on the raw water pump.

Dean

 

[geem]

The exhaust elbow, especially if it's cast Iron, tends to block in the exhaust gas part first then the water part. If its the same elbow as the 2010. Eventually the carbon will block the water side as well. Certainly worth a check. Our 2010 engine ( Perkins equivalent) that is our generator, show symptoms of lack of power when the exhausting is carboned up

 

[Daydream believer]

Probably a bit late now as the post is 3 weeks old so this comment is really for others with similar issues . Apologies if some repeat of earlier comments.

When the engine is running feel the bellows each end of the heat exchanger. If they seem difficult to compress ( compared to when not running) it will suggest pressure in the water going through the bellows. The aft one will be pressured if the exhaust is becoming blocked. If this is not the case & the front one is more pressurised then the heat exchanger itself may need cleaning. Not difficult to do. Just remove the bellows & rod through with a welding rod. The OP says his one is clean, so not relevant to him.

Re tranona's suggestion about the cover plate on the pump. I know that you say that the cover is only lightly scored. Even a small amount of scoring causes a loss of pump pressure, sometimes preventing the system from self priming. A simple solution is to clean the paint off the opposite side. Lightly abrade the surface where the serial Nos may have slight projections, then turn the plate round & fit back to front. You might need a compound to help seal the joint, as the paper gasket is not particularly good. I use a blue one - forget the name.

 

[Beneteau381]

My experience of an MD 2000 was overheating when working hard is
either as result of a blockage in the injection of s3a water post heat exchanger into the exhaust elbow
Or a blockage in the closed circuit water circulating through the heat exchanger.

I would test as follows.
Do you have a good stream of flow of water out of the exhaust?

If not you likely have a blocked exhaust elbow injection point or a less common blocked heat exchanger from a broken up impeller.

If good flow when your engine alarms try putting your hand in the stream of water from the exhaust.

If it is relatively cool ie you can get your hand in it without scalding then the problem is in the closed circuit water flow and a lack of heat exchange.

The flow can be restricted if your antifreeze has not been changed every two years which will cause internal engine waterway corrosion.

Restrictions can be caused by either blocked thermostat,collapsed hoses to and from circulation pump, blockage of the aluminium spigot on the cooling water manifold exit, or very uncommon failure of the engine circulation water pump.

Steve

Youve niled it Steve, just done my mates in Portugal

 

[Beneteau381]

Thanks Steve for reply ill check for blockages at the exhaust elbow.
Exhaust water is warm but not hot.
Seems to be good circulation to calorifier on fresh water system.
No real wear on the raw water pump.

Dean

it will be in the little spigot

 

[Farrell]

Hi Steve, just done my mates in Portugal

Hi Steve
Stripped exhaust elbow cleaned best you can water flows through from pouring in the top.
Still have the same problem over heat while working hard.
2000rpm will run for 2 hours then alarm but under more load get a fast overhear alarm Elbow not easy to clean and see if clean.
Guessing just change it so I know it’s correct.

 

[geem]

Hi Steve
Stripped exhaust elbow cleaned best you can water flows through from pouring in the top.
Still have the same problem over heat while working hard.
2000rpm will run for 2 hours then alarm but under more load get a fast overhear alarm Elbow not easy to clean and see if clean.
Guessing just change it so I know it’s correct.

If you can't clean it and be sure you have a decent sized aperture for both exhaust gases and water flow then replacement with a s/s version makes sense. The water opening on my elbow is about 19mn diameter.

 

[Daydream believer]

If you can't clean it and be sure you have a decent sized aperture for both exhaust gases and water flow then replacement with a s/s version makes sense. The water opening on my elbow is about 19mn diameter.

It is not just the aperture. I think that the CI one has an inner lining that takes water as well. I did not know this, but gave my old one to a friend. He cleaned it out with acid & says that there are 2 skins to the jacket. I have not checked so cannot confirm. If true then it is not just a case of cleaning the 19mm outlet.

 

[geem]

It is not just the aperture. I think that the CI one has an inner lining that takes water as well. I did not know this, but gave my old one to a friend. He cleaned it out with acid & says that there are 2 skins to the jacket. I have not checked so cannot confirm. If true then it is not just a case of cleaning the 19mm outlet.

It's effectively a tube within a tube. The point is it shouldn't lose cross sectional area within the elbow or you restrict flow. It's not hard to look in to either end of the elbow with a head tourch and see what is going on. I clean mine with a dremel and restor it to full crossectional area. I used to have to do it every 100hrs with a cast Iron elbow. Now it's every 500 hrs with a cast s/s elbow. I think the thinner wall of the s/s elbow has less thermal inertia so it heats up faster. It probably has better heat transfer as well so it spend less time as a cool surface for the moisture in the full to condense on to. Just my thoughts. No idea if that is the case

 

[Daydream believer]

A friend of mine- The one I gave the old Volvo elbow to- bought a SS one & it disintegrated within 3 years,
The welds went & a coded welder in our club said that the metal was past welding. I do not know the full story but something had happened to its structure.
I think that one can buy good elbows & bad elbows. How one knows if they are any good is anybodies guess.
How does an importer know what is good or bad? Until the complaints come in that is. By then he has probably changed suppliers & the experiment starts again.

My friend has a Beta & a standard Beta part is no longer available. However, he used my old elbow as a pattern & found that he could make a volvo one fit, with a bit of reeming to the holes.
He was going to use my old elbow, but found that after extensive cleaning, it had a hairline crack that neither of us could see at first sight. Something to look for when cleaning dirty elbows.

 

[geem]

A friend of mine- The one I gave the old Volvo elbow to- bought a SS one & it disintegrated within 3 years,
The welds went & a coded welder in our club said that the metal was past welding. I do not know the full story but something had happened to its structure.
I think that one can buy good elbows & bad elbows. How one knows if they are any good is anybodies guess.
How does an importer know what is good or bad? Until the complaints come in that is. By then he has probably changed suppliers & the experiment starts again.

My friend has a Beta & a standard Beta part is no longer available. However, he used my old elbow as a pattern & found that he could make a volvo one fit, with a bit of reeming to the holes.
He was going to use my old elbow, but found that after extensive cleaning, it had a hairline crack that neither of us could see at first sight. Something to look for when cleaning dirty elbows.

Mine is a cast s/s elbow. No welds. Perfect after 5 years. It has been used for approximately 1200 starts and stops of the engine over that period as its a generator. Mine was supplied as a Northern Lights generator part. I bought whilst we were in West Palm Beach, Florida. Its nicely made and wasn't expensive. About $180 US at the time

 

[MikeBz]

A friend of mine- The one I gave the old Volvo elbow to- bought a SS one & it disintegrated within 3 years,
The welds went & a coded welder in our club said that the metal was past welding. I do not know the full story but something had happened to its structure.
I think that one can buy good elbows & bad elbows. How one knows if they are any good is anybodies guess.

I bought a fabricated SS elbow from Parts4Engines, the weld cracked after a few years. Ian at East Coast Stainless said it was down to the type of weld (I can’t remember the terminology) and rewelded it for a very reasonable sum. I wouldn’t buy a fabricated one again.

 

[geem]

This is what I fitted. The discharge direction of the exhaust was slightly different but it caused no problems