Bronze Raw Water Pump Elbows

[kiwisailor]

So I'm replacing my raw water hoses and looking to install new elbows on the new (last season) Oberdorfer N202M-03 water pump. I'm having a real issue finding new "bronze" elbows with 1/2npt and 5/8 barb that will be able to be installed in the small distance between both inlet and outlet ports.

Wondering what others did in this situation or where to purchase small bronze elbow fittings etc?

 

[bgary]

1/2npt and 5/8 barb

I couldn't find 1/2"-NPT x 5/8"-barb elbows either, so I used 1/2" hose. Much easier to find 1/2"-NPT x 1/2"-barb elbows, and easy to install

https://www.fisheriessupply.com/midland-metals-90-degree-pipe-to-hose-adapter

My "logic" was that since the pump inlet and outlet are 1/2", I would get the same flow through the pump with 1/2" hose as I would have gotten with 5/8" hose. So far it's been working great (N202M-16 on a Universal M25)

But take this with a grain of salt, the amount I know about motors would not fill much space.

Bruce

 

[Baslin]

Try and find bronze street elbows...It may require a couple of fittings for each elbow but you can make it work.

 

[Christian Williams]

I used the old ones. Why not?

 

[kiwisailor]

I used the old ones. Why not?

One of the existing ones is just a 1/2 npt to 1/2 npt close nipple....no barb on the end. Seeing as I'm installing a new raw water strainer and replacing hoses I want to do it right. I may end up with new elbow male/female and then a 1/2npt to 5/8 barb to fix the issue.

 

[kiwisailor]

I couldn't find 1/2"-NPT x 5/8"-barb elbows either, so I used 1/2" hose. Much easier to find 1/2"-NPT x 1/2"-barb elbows, and easy to install

https://www.fisheriessupply.com/midland-metals-90-degree-pipe-to-hose-adapter

My "logic" was that since the pump inlet and outlet are 1/2", I would get the same flow through the pump with 1/2" hose as I would have gotten with 5/8" hose. So far it's been working great (N202M-16 on a Universal M25)

But take this with a grain of salt, the amount I know about motors would not fill much space.

Bruce

I see the elbows are brass in the link. Isn't that a no-no bronze (pump) to brass fittings? That is the problem I can find brass elbows just not bronze one piece elbows.

 

[Christian Williams]

No brass in a salt-water circuit. OK for fresh.

I was surprised at the salt build-up in my fittings. Any running-hot problem, first thing to check.

 

[Pat O'Connell]

Brass Heat Exchanger Elbows

We used brass elbows 35 years ago on the strainer, heatexchanger and raw water pump. My bad but they still seem to be OK. You all reminded me to check them this spring. We will give them a good look when the cover comes off the boat in April. Pat 1981 E28+Universal 5411
BTW: I was just looking at information on dezinced (sp) brass fittings and I just can't believe that the fittings we used 35 years ago were brass. They would have fallen apart by now and I take very good looks at the engine all summer. I must have blundered into using bronze?

 

[Sean Engle]

Issue in Posting?

I'm just seeing this...

So there was a blank thread posted... Have you seen any others? Is the thread you're referring to?

http://www.ericsonyachts.org/infoexchange/showthread.php?12806-M25-Raw-Water-Pump-Replacement


//sse

 

[GrandpaSteve]

Link to blank thread

I'm just seeing this...

So there was a blank thread posted... Have you seen any others? Is the thread you're referring to?

http://www.ericsonyachts.org/infoexchange/showthread.php?12806-M25-Raw-Water-Pump-Replacement


//sse

Hi Sean - here is the link to the blank thread:

http://www.ericsonyachts.org/infoex...iversal-M25xp-Raw-Water-Pump-Replacement-Help

 

[GrandpaSteve]

Oberdorfer Raw Water Pump Replacement

I am replacing my Oberdorfer with a new Oberdorfer pump because it looses suction, probably from a worn face plate, and probably a worn cam. It also started leaking this year, and I believe it has been rebuilt before (old bearings in a PO toolbox).

The pump is the N202M-15 (3/8" ports). The original hose adapters are brass (one straight, one 90 degrees), and look strong as can be, no pink anywhere. I am inclined to reuse the adapters, since they seem to have been fine for 30 years. My theory is that their location in the system does not expose them to galvanic corrosion. They took quite a bit of pressure in the vice to remove.

I cannot find 3/8" bronze NPT anything anywhere.

I could order a 1/2" port pump, but then I have to change my seacock, sea strainer, hoses (which are only 4 years old) and maybe make up some adapter for the heat exchanger.

I am sharing this to get any input before ordering the new pump.

Thanks for any feedback.

 

[Kenneth K]

I ran into the same problem. Bronze fittings are cast, and they only seem to make them down to about three quarters of an inch. Below that you're forced to use brass.

Brass is supposed to be a No-No in this application, but the old brass ones seemed to have worked just fine. Maybe the old ones were red brass. Red and yellow brass are right next to each other on the galvanic scale, however, once all the zinc is corroded you're left with much more copper in a red brass fitting than a yellow brass fitting, making it the much preferred choice.

My preference would be use the old fittings if you can. If you can't, you'll have to go with new red or yellow brass. Obviously red brass fittings would be better if you can find them.

I asked several mechanics what they use, and they all said brass fittings. I asked them about the galvanic corrosion. No one quite knew why, but some suggested that this part of the engine may also be protected by the pencil zinc in the heat exchanger. The metal is all connected and it's in contact with the same flow of salt water. So maybe that's true.

There's no perfect answer here, only workable ones.

 

[GrandpaSteve]

I can use the old fittings, and will order the new pump based on that.

 

[kiwisailor]

Business opportunity!

I am replacing my Oberdorfer with a new Oberdorfer pump because it looses suction, probably from a worn face plate, and probably a worn cam. It also started leaking this year, and I believe it has been rebuilt before (old bearings in a PO toolbox).

The pump is the N202M-15 (3/8" ports). The original hose adapters are brass (one straight, one 90 degrees), and look strong as can be, no pink anywhere. I am inclined to reuse the adapters, since they seem to have been fine for 30 years. My theory is that their location in the system does not expose them to galvanic corrosion. They took quite a bit of pressure in the vice to remove.

I cannot find 3/8" bronze NPT anything anywhere.

I could order a 1/2" port pump, but then I have to change my seacock, sea strainer, hoses (which are only 4 years old) and maybe make up some adapter for the heat exchanger.

I am sharing this to get any input before ordering the new pump.

Thanks for any feedback.

We are in the "same boat" figuratively ;-) . How can it be that a pump manufacturer sells a pump with 3/8 npt ports but no one makes 3/8 to x/x pipe to barb elbows. I've looked high and low and will have to use a combination of 3/8 close nipples, a 1/2 to 3/8 reducer, 1/2 elbow and 1/2 to 5/8 pipe to barb or a 3/8 elbow to 3/8 close nipple to 1/2 to 3/8 reducer to 1/2 to 5/8 barb. What a cluster f......when all we need is a 3/8 to 1/2 or 5/8 barb that is less than 1.5 inches long. This explains my current setup of a close nipple being used as the hose barb!

I'm about ready to locate a foundry to make these and start selling them on eBay at $15 a pop.

Rant over.

 

[GrandpaSteve]

Sherene and Mike - I see you are in Groton, maybe you could get them made at the Sub base! They fabricated so much custom stuff for my old boat back in the day - USS Billfish SSN-676.

 

[Pat O'Connell]

Bronze fittings

Hi Respected Sailors Sorry. Need to clarify earlier post where I said that we used all brass when we plumbed our heat exchanger and pump. I looked at my prior heat exchanger and pump in the basement. Fresh water fittings are all brass! Salt water fittings are bronze.
I guess 30 years ago I knew how to do it? Best Regards Pat O'Connell 1981 E28+ Universal 5411 SenDure Heat Exchanger

 

[dxulander]

Can't find anything of size in bronze (for me it's the 3/8 NPT male to 5/8 hose barb), but did find some on amazon in stainless steel. Any old sailors have experience between bronze and SS interaction?

Part: https://www.amazon.com/Beduan-Stain...0009e97ddc&ref_=pd_gw_ci_mcx_mr_hp_atf_m&th=1

I know what chatgpt is telling me.

 

[bigd14]

Figuring out hose and pipe fittings is worse than the math course I had to take twice.

I too used brass fittings for my recent water pump replacement. Luckily I am in fresh water.

My current plumbing dilemma is a leaky reducer in the coolant loop that I cobbled together out of various stainless fittings. The outlet hose from the manifold is 7/8” and the inlet to the custom HX mounted above the engine is 5/8”. Neither of these are standard hose or fitting sizes so they don’t play nicely together and leak. I just cannot get them to seal completely. The engine is Japanese and the custom HX was installed by a PO in Canada so I believe they are metric fittings. My Googling skills weren't advanced enough to source metric reducer fittings and hoses. The leak is minor right now but eventually I’ll need to fix it properly. If I can’t figure it out I may resort to having one fabricated.

 

[Loren Beach]

FWIW, I had to use heavy duty "T Bolt" hose clamps when I changed up to a larger OD exhaust hose for our new diesel. That wire reinforced hose is really stiff and it takes more clamping pressure to attain a solid attachment.

 

[Kenneth K]

so I believe they are metric fittings.

Have you tried BSP (British Standard Pipe) fittings. Apparently BSP and JIS (Japanese Indus. Std.) are the same. An oil fitting on my M-25, and my Yanmar exhaust elbow are both BSP.