Raw water intake ball valve on Volvo 150S saildrive

[ohthetrees]

Hello, I’m doing some engine work, and I don’t like the way the crappy (brass?) ball valve feels on my raw water intake (integral to the sail drive).

The old one is in my hand and stamped “made an Italy DN 25 PN50 MS 58”

The threads appear to be tapered and very close in size to NPT 1 inch.
As someone who is easily confused between metric, imperial, British threads, American Threads etc., and a little scared just to purchase a 1 inch USA specification ball valve and go for it. I know threads that “kind of“ work will not cut the mustard. Does anyone know whether such a valve would work?

I’ve had a bit of a Google, an answer does not leap forth.

Anyone familiar with the Volvo sale drive-in question, or just knows a lot about pipe threads, I’d appreciate some advice.

[Wotname]

I don't know a lot about pipe threads but I know a little bit

DN means Nominal Diameter (actually Diameter - Nominal). 25 will mean 25 mm
PN means Nominal Pressure (actually Pressure - Nominal). 50 will mean 50 bar
MS 58 is a DIN standard for Brass. Google for more detail here is one link Material Brass

Thread is most likely to be a BSP (Bristish Standard Pipe) which is also the same as an European standard DIN thread.

IIRC, The female part is usually a parallel thread and the male part will be a taper thread, both BSP of course.

[ohthetrees]

Thanks a lot for that info! Does anyone know if BSP threads are used throughout Europe, or just Britain? What a pain that the world can’t get on the same page about this stuff.

[mikedefieslife]

Tapered BSP threads aren't very common. Most fittings you buy in Europe are BSPP rather than BSPT. There are also metric connections too but these are less commonly used.

[Wotname]

Originally Posted by ohthetrees

Thanks a lot for that info! Does anyone know if BSP threads are used throughout Europe, or just Britain? What a pain that the world can’t get on the same page about this stuff.

BSP is standard common thread (DIN standard) all around the world except north America although the I don't know about central and south America.

There are various other specialised threads in industry of course but for mum and dad general plumbing and piping, BSP is the goto thread. North America is NPT.

[ohthetrees]

Thanks very much for the info. I guess next thing for me is to try to source a DN25 BSP ball valves. Somehow. Do all Volvo Penta USA owners have this conundrum I wonder?

[Wotname]

Originally Posted by ohthetrees

Thanks very much for the info. I guess next thing for me is to try to source a DN25 BSP ball valves. Somehow. Do all Volvo Penta USA owners have this conundrum I wonder?

It is possible that VP has specified NPT threads for their NA products.

Yanmar usually doesn't do that but they do it on some of their engines or so I've have been told.

You could find the cheapest NPT threaded ball valve sold near you and do a comparison.

[Jahwork]

Hola,

Not sure if this will be of value in solving your problem, but I recently abandoned both of my SD20 saildrive raw water intake valves, plugged them with a BSPP 316SS plug and installed a traditional thru hull in each engine room with Groco flange adapters and groco valves/mushroom fittings. I am much happier with this set up. At any rate, I believe your saildrive will also have BSPP threads, which as others have pointed out are also known as DIN the world over.

Safe journeys from a fellow Seattle-ite,

~Jake

[ohthetrees]

Thanks Jake, I hope it doesn’t come to putting in yet another thru Hull.

Does anyone know where to source BSP fittings like this in the USA? I’m striking out with my usual sources.

[Stu Jackson]

Perhaps www.marinehowto.com can help, at least in identifying threads. IIRC, Maine Sail has a discussion about it, probably in thru hull fittings. Good luck.

[Mongo_at_sea]

groco now makes BSPP fittings. Look on their online catalog. I also closed off the saildrive valve and added a new thru hull and raw water strainer.

[flackster]

Hey everyone... I just swapped out this same thing. The threads inside the engine were normal NPT 1" - check this out $100 vs $350. All found at a good local plumbing / hydraulic store. This was on a Volvo 150S drive.

[flackster]

Update... I'm replacing that nipple with a cast bronze one vs the brass one shown. Still $14 at West vs $45 at Volvo.

Brandon