Volvo MD31

[Monique]

Hello forum folks,

A friend is looking at a boat equipped with MD31 engine.

He is unsure about the genealogy of the MD31; which engine does it come from? How reliable are they?

Thank you

 

[Trundlebug]

Not sure what it comes from but my boat has twin MD31A's.
It's a 2.4L N/A 4 pot diesel, direct injected.

Very reliable, and economical.

 

[pvb]

He is unsure about the genealogy of the MD31; which engine does it come from?

I believe it's a VP-designed engine.

 

[Monique]

Volvo in house? Strange...

 

[Trundlebug]

Yes, but made by Perkins, as per many others.

 

[scottie]

Yes, but made by Perkins, as per many others.

Sorry but incorrect definitely built by Volvo and not in car or truck factories but in purpose built factory
Some instances of the original 30 series being used commercially and a few in small trucks
It was developed into the kad32

 

[KellysEye]

The MD series are built like a brick outhouse, they are not lifed like a modern engine which is designed for 8,000 hours. I once asked Volvo what it would cost to build an engine to the quality of MD now, the answer was 16,000 pounds which is why no engine is built to that quality now. So to answer the question the MD's are reliable because of the build quality.

 

[scottie]

Again not quite true as in Volvo speak MD translates as Marine Diesel and can be used to designate many different units from 7-700+ hp
The 30 was described as a high speed unit as I recall
It was a very good yacht engine especially as a de rated unit though

 

[Trundlebug]

Sorry but incorrect definitely built by Volvo and not in car or truck factories but in purpose built factory
Some instances of the original 30 series being used commercially and a few in small trucks
It was developed into the kad32

Perkins is a purpose built engine factory - not necessarily truck or car.
Their engines (and those made by them badged as others eg VP) are and have been used for a complete spectrum of applications.
Perkins have made engines for VP for many years. Of all kinds. Some automotive based, some bespoke VP design (as in this case).
Don't assume that because it wasn't used in other (automotive) applications it was necessarily made in a VP factory.
Nothing wrong with Perkins either, they've been making engines for years, quietly and behind the scenes but they know what they're doing and have a good reputation.
It's certainly no slight to say they put it together. The base design is more of a quality indicator.

 

[Tranona]

Perkins is a purpose built engine factory - not necessarily truck or car.
Their engines (and those made by them badged as others eg VP) are and have been used for a complete spectrum of applications.
Perkins have made engines for VP for many years. Of all kinds. Some automotive based, some bespoke VP design (as in this case).
Don't assume that because it wasn't used in other (automotive) applications it was necessarily made in a VP factory.
Nothing wrong with Perkins either, they've been making engines for years, quietly and behind the scenes but they know what they're doing and have a good reputation.
It's certainly no slight to say they put it together. The base design is more of a quality indicator.

This may well be true - but does not mean that all Volvo engines are Perkins base. Older engines (like the MD31) are either Volvo designed and made or use a Puegeot base. The Perkins engines came in during the 1990s, first with the MD22 type that use the BL Montego engine built by Perkins and then the MD20X0 series from the Perkins/Shibaura factory in Japan. The latest small engines are also Perkins Base, some from Japan and some from Peterborough.

 

[scottie]

Having been in the factory watching them being built I can say it is a volvo built unit and neither peugot nor Perkins

 

[KellysEye]

As you say Volvo MD engines stand for Marine Diesel they were not marinised car engines as many yacht diesel engines are now.

 

[Ukeluthier]

I recently sold a 45' cutter I had owned for 32 years, and I was the original owner. It still had the original Volvo Penta MD21B installed in Taiwan when the boat was built in 1981.

When the boat was being commissioned in Miami, Florida, the Volvo mechanic who did the engine work told me that the MD21B was a marinised Peugeot engine... the same block as used in the Peugot 504 car. My recollection is dimming somewhat, but I seem to recall that once long ago -- when I needed to replace the starter -- I was able to use a rebuilt Peugot 504 starter.

If this is indeed the case, it sort of blows the theory that all the Volvo MD-series engines were produced from the bottom up by Volvo out of the water.

 

[Tranona]

As you say Volvo MD engines stand for Marine Diesel they were not marinised car engines as many yacht diesel engines are now.

That is just not so! As I said above the MD22 is a BL Montego unit (its predecessor the MD21 was a Peugeot) and the 40hp and under engines (such as the MD 20X0 series) since the early 90's have been Perkins industrial units as used in many construction, industrial and garden machinery.

 

[scottie]

Just to make it clear the M means the engine whatever it's basic source is used in a Marine application driving through a gearbox or sail or jet drive
Outdrive versions were AQ for AQuamatic
The 2000 series were a deviation from this and the 20 series another deviation
I would think that Kelly's eye may be referring to Md1/2/3 11/17 engines which were a Volvo family unlike MD5 (Norwegian) and MD 6/7 which were derived from Albin in Denmark