Yanmar SD20 Kingston Seacock raw water valves

[kiltym]

About every 2 years I have to replace the valves that screw into the SD20's for the raw water cooling of my engines.

Since the last time I replaced them (about 18 months ago), I have religiously opened and closed them every week, as well as apply some oil to them in an attempt to keep the working. But, now they are getting stuck. I know each valve requires about 10 rotations to fully close, and now cannot get that many turns, about 8.5, and have broken the SS stem by applying to much pressure when (carefully) trying to loosen them up.

Why Yanmar does not make these with a ball valve is beyond me.

Has anyone found a good replacement ball valve for these? When I have tried to assemble something it turns into about 8" long and I worry about having something that long sticking out the side of the SD in case it got stepped on.

Thanks in advance for any suggestions. I can easily put a Marelon ball valve inline in the hose, and simply ignore the valves at the SD, but would prefer to just eliminate them all together.

[colemj]

The valves on the Volvo saildrives are ball valves. Perhaps those have the same threads and will fit instead?

Mark

[kiltym]

Thanks. Will check into this and post what info I find if they might fit.

[kiltym]

Oh yea, is there a specific model Volvo saildrive I should be looking at?

Probably their smallest one?

[colemj]

The 120S is the model we have and the ball valves screw onto a nipple in the saildrive housing. I would guess the diameter is ~16mm.

I don't know if the Yanmar valves are similar.

It seems like any ball valve you can find with the correct threads would work.

Do yourself a favor and on the next haulout install dedicated thruhulls/valves for the engines. That's how ours are and the saildrive valves are capped off. No messing with barnacles or valves, etc.

Mark

[kiltym]

Yes, have thought about a separate thru hull as I know you have, but so far we have had no issues with water flow through the drive unit itself.

I have looked for generic ball valves, but as I wrote before, by the time I assemble all the parts together to go from the SD thread to the hose barb, its like 8" long and annoying. The nice thing about the Yanmar valve is it is compact, and has the correct fittings forged into it, not added to it as would need to be done with a standard ball valve. But, life is a compromise, just want to come up with a good solution to replace them with when the opportunity arises.

I have to imagine someone has done this already. I cant be the only one with 6 sticky valves in 6 years.....

[colemj]

I don't know what the Yanmar one looks like. The Volvo looks like a short pipe nipple screwed into the saildrive with an Apollo-style ball valve screwed onto it. The whole thing is about 4" long.

The problem is probably the metric threads - maybe you will have better luck finding parts that fit directly now.

Mark

[kiltym]

The Yanmar ones are essentially a single piece unit with a thread on one side, a hose barb on the other, and the handle for the valve. The total size is more like 2”. It’s a nice little piece of work, if only they used a ball valve.

Do you know what material the nipple is that attaches to the SD? I have read about some people using SS, which seems crazy to me on am aluminum SD.

The ones from Yanmar look like brass, but seems more likely it is polished bronze.

Also found a material called DZR brass, is this suitable on a boat? Just curious as I thought you might know.

I assume I should assemble bronze fittings for it, and once I find all the bits and correct sizes I will post everything here.

[colemj]

Ours are definitely some type of bronze, although bronze is about the same from aluminum galvanically as SS. Ours are bedded with a thick compound in the threads. Sounds like the Yanmar ones are more compact.

I don't know anything about DZR brass, but it seems like a good fit for a boat and aluminum.

You can always get aluminum valves and pipe fittings if you are worried. Also monel, if you find a lot of money...

Mcmaster-carr sells all sorts of pipe and valves in different materials if you find a way to ship to where you are.

The Gambiers must have quite the hardware stores!

Mark

[kiltym]

No good hardware stores, but the baguettes more than make up for it.....

Thanks for the additional info.

[mfeene01]

Hi Mark. Hope things are well. Say Hello to Leisbet for us.

As far as the valves go, I put a ball valves between the sail drive units and their raw water strainers. Haven't tried to turn off the Yanmar valves since.

No mus, no fuss and it's easy to clean the strainers.

Mike & Patti
Lauren Marie

[gspeak]

Had our Yanmar SD20 valves replaced with S/S elbows, nipples & ball valves at Easter.

This is the parts list the mechanic billed me for:
2 x #45545 Valve Ball S/S 15mm 1/2"
2 X #3HN015 Hex Nipple 15NB 1/2" 316S/S
Elbow S/S 1/2"

See photos:





Dave

Seabreeze
L380 #241

[kiltym]

Originally Posted by gspeak

Had our Yanmar SD20 valves replaced with S/S elbows, nipples & ball valves at Easter.

This is the parts list the mechanic billed me for:
2 x #45545 Valve Ball S/S 15mm 1/2"
2 X #3HN015 Hex Nipple 15NB 1/2" 316S/S
Elbow S/S 1/2"

See photos:

Dave

Seabreeze
L380 #241

Thanks.

Couple of questions if you don't mind.

The threads are BSP, correct? As opposed to NPT. I think you are in Australia based on photo links, and assume there it is BSP?

What is the thick red paste used on the threads? Obviously some type of pipe dope, was this instead of teflon tape, or something to help insulate the SS from aluminum?

No worries about the stainless and aluminum saildrive becoming permanently bonded due to corrosion?

Thanks again for any further info.

[gspeak]

Originally Posted by kiltym

Thanks.

Couple of questions if you don't mind.

The threads are BSP, correct? As opposed to NPT. I think you are in Australia based on photo links, and assume there it is BSP?

What is the thick red paste used on the threads? Obviously some type of pipe dope, was this instead of teflon tape, or something to help insulate the SS from aluminum?

No worries about the stainless and aluminum saildrive becoming permanently bonded due to corrosion?

Thanks again for any further info.

Mark,
Sorry I can't give you a lot of detail as I left it to the mechanic who said he has done a lot of these conversions. He did give me the option of going with new dedicated through hulls for the conversion also, but I went with replacing the Yanmar valves as I prefer less holes in the hulls.

I'm pretty sure they are BSP threads, but not 100% sure. Not sure of the paste used also, but have a feeling he used thread tape as well. Maybe the paste is used to isolate even more.

I assume that the corrosion problem with the dissimilar metals is hopefully being taken care of by the pencil anodes in the sail drives, which he also replaced.

Maybe someone else can chime in with their take on the particulars.

Dave

Seabreeze
L380 #241

[colemj]

This is exactly what our Volvo's look like, except the fittings are bronze and the thick pipe dope is yellowish.

Mark