question on a shut off valve

[luna]

It is not uncommon for these types of petcock valves to internally seal with a metal to metal contact. If so, there is not a rubber sealing washer inside the valve, just two machined steel surfaces that come in contact with each other that provides the seal.
Operators of and Distributors for the valve who don't know which way to turn it can damage these mating surfaces by forcing it one way or the other in frustration. So can time, through corrosion damage it.

Your valve, which may well be original (as there is still red paint in the wings) shows evidence of these mating surfaces weeping with the pile of corrosion products around the left hand threaded tube.

If the petcock fails while you are at the helm you will only know if you are watching the Temp. gauge or have an alarm. At best this experience will be inconvenient, messy and annoying. At worst it could mean an engine.

I would do the $30 worth of preventative maintenance now and change it. Pick your poison.

A similar thing may well be going on at the brass cap that holds the pencil zinc in your heat exchanger's port.

I suspect that over the years, through multiple zinc replacements the mechanics have overtightened the cap to the point where the metal to metal mating surfaces of the threads in the port on the heat exchanger are simply worn out. Now they weep, resulting in the white powder. Oh joy!

NPT threads were never intended to be used in a situation where you are advised to open the joint and inspect the innards monthly. That is what straight threads and a sealing washer are designed to do.

You could try a new brass cap and pipe dope, but do not tighten the fitting up more than about half a turn past hand tight or until it just visibly stops leaking.
A vacuum and a tooth brush are your tools to deal with this until it is time for a new heat exchanger.

 

[paulga]

It is not uncommon for these types of petcock valves to internally seal with a metal to metal contact. If so, there is not a rubber sealing washer inside the valve, just two machined steel surfaces that come in contact with each other that provides the seal.
Operators of and Distributors for the valve who don't know which way to turn it can damage these mating surfaces by forcing it one way or the other in frustration. So can time, through corrosion damage it.

Your valve, which may well be original (as there is still red paint in the wings) shows evidence of these mating surfaces weeping with the pile of corrosion products around the left hand threaded tube.

If the petcock fails while you are at the helm you will only know if you are watching the Temp. gauge or have an alarm. At best this experience will be inconvenient, messy and annoying. At worst it could mean an engine.

I would do the $30 worth of preventative maintenance now and change it. Pick your poison.

A similar thing may well be going on at the brass cap that holds the pencil zinc in your heat exchanger's port.

I suspect that over the years, through multiple zinc replacements the mechanics have overtightened the cap to the point where the metal to metal mating surfaces of the threads in the port on the heat exchanger are simply worn out. Now they weep, resulting in the white powder. Oh joy!

NPT threads were never intended to be used in a situation where you are advised to open the joint and inspect the innards monthly. That is what straight threads and a sealing washer are designed to do.

You could try a new brass cap and pipe dope, but do not tighten the fitting up more than about half a turn past hand tight or until it just visibly stops leaking.
A vacuum and a tooth brush are your tools to deal with this until it is time for a new heat exchanger.

is this thread dope good for the threads on both the t stat housing and the zinc?

 

[luna]

Permatex's #2 Form a Gasket is said (on the back of the package) to be useful to seal threads. That said, I have never used it for that purpose. I do use it on occasion to stick gaskets to one side of an assembly.

I would use a purpose made pipe dope, lots of them exist. Here is one that is good plus you get twice as much for the about the same price.

Amazon.com

 

[paulga]

Permatex's #2 Form a Gasket is said (on the back of the package) to be useful to seal threads. That said, I have never used it for that purpose. I do use it on occasion to stick gaskets to one side of an assembly.

I would use a purpose made pipe dope, lots of them exist. Here is one that is good plus you get twice as much for the about the same price.

Amazon.com

Thanks.
on the other end of the heat exchange, the fresh water drain plug is dripping.
what could be the cause that started the leak?

 

[TJM]

Keep reading up on valves. There is a huge difference in ball valves, gate valve, check valves, petcocks etc..... Be careful about information from "reps" or anybody else for that matter. Internet jockeys can throw out all kinds of information without buying a new engine block when yours seizes up.
Parker Hannifin is great resource of hardware.
Sometimes people use brass fittings in engine blocks for safety. If they get wacked- the fitting will deform and bend as opposed to a broken thread in your block, just another perspective.
Galvanic corrosion is also at play. It is better that the fitting corrode vs your engine block. Think of your zincs.
As far as the heat exchanger zinc, yes you have outside corrosion. It is probably cause from a leak in that fitting. Salt water sneaking out of the joint and causing the crusty. I would wire brush the crystals away and remove the threaded zinc carefully, CCW. You can inspect upon removal and replace as needed.

There are a few different positions on whether to use any kid of thread sealant on zincs. I DO, It eliminates any leaks (such as your) and prevents over tightening.

Looking at your engine, you can use "Rustoleum Regal Red" as touch paint. It makes the ER look great.

 

[KnotYet]

Keep reading up on valves. There is a huge difference in ball valves, gate valve, check valves, petcocks etc..... Be careful about information from "reps" or anybody else for that matter. Internet jockeys can throw out all kinds of information without buying a new engine block when yours seizes up.
Parker Hannifin is great resource of hardware.
Sometimes people use brass fittings in engine blocks for safety. If they get wacked- the fitting will deform and bend as opposed to a broken thread in your block, just another perspective.
Galvanic corrosion is also at play. It is better that the fitting corrode vs your engine block. Think of your zincs.
As far as the heat exchanger zinc, yes you have outside corrosion. It is probably cause from a leak in that fitting. Salt water sneaking out of the joint and causing the crusty. I would wire brush the crystals away and remove the threaded zinc carefully, CCW. You can inspect upon removal and replace as needed.

There are a few different positions on whether to use any kid of thread sealant on zincs. I DO, It eliminates any leaks (such as your) and prevents over tightening.

Looking at your engine, you can use "Rustoleum Regal Red" as touch paint. It makes the ER look great.

Keep in mind that in order for a zinc to protect anything it must make electrical
contact with it. I would either use nothing and check/clean/replace as needed, or
a metal based anti-seize compound that promotes a decent electrical connection.

 

[KnotYet]

Thanks.
on the other end of the heat exchange, the fresh water drain plug is dripping.
what could be the cause that started the leak?

View attachment 161388

It looks like that water drip originates from the hose connection above it.
It may not be the culprit after all...

 

[SteveK]

@KnotYet
sure does look like several stains and a fresh stream in photo.

 

[Greg QS]

I didn't find the material of the engine block in the manual. the manual mentioned "Any fittings used to connect the hose to the gallery must be of steel or malleable iron composition. Brass must not be used for this application"

if i search "steel elbow" i got either stainless steel or brass. by steel, do you mean malleable iron or stainless steel?

Its called black iron or galvanized pipe. You can source at the local hardware store or box stores. Commonly used for gas pipe.

 

[BruceK]

...I too, dislike the wing petcocks. They’re just too fragile.

I`m thinking those pissy little "wings" on the petcock are to discourage use of force by failing before the screw they operate.

 

[luna]

You are discouraged to use force or tools to operate these "pissy little" petcocks because inside, the mating surfaces that affect the seal are quite delicate. It also helps if it is well lubricated and you know how to turn it on.

Now, getting your mind out of the gutter, to determine if it's the hose or the drain plug on the heat exchanger that is leaking, clean and dry everything in the vicinity, then using some colored shop towels (Blue or Brown work well) and a twist tie, wrap a 1/2"+/- wide piece around the fitting that has the female threads in it and twist tie it on. Be careful to ensure that there is no contact between the towel and coolant that would leak from the plug itself. Wait and see if it gets wet. The Blue or Brown towels will darken significantly when wet.

My guess it will not get wet and therefore the leak is at the plug.

Let us know your findings.

 

[paulga]

Thanks.
I will trace and test over the weekend.

 

[paulga]

It is evident that the FL135 has a difference in this area. The FL120 has a purge valve at the forward end of the exhaust manifold jacket. This is a high point and has to be vented when filling with coolant.

On the FL135 I see from this (excellent) photo that the top of the header tank is higher than the end of the exhaust manifold jacket, so Lehman was able to run a tiny hose from the exhaust manifold jacket to high up on the header tank. This hose lets the air trapped in the exh manifold move into the header tank when filling.

Thanks.
I found the manual says on page A19: "these engines (2722E-2728E) are fitted with a cooling system de-airation service and no bleeding of the manifold is required during system filling"
and illustrates this on the next page. but the handwriting is difficult to tell: "xxxx bleed"

 

[SteveK]

Did you find that manual in the forum resource section? If not go ahead and add it.

 

[High Wire]

the manual says to check the zinc condition on the heat exchanger monthly and clean zinc debris from inside of the heat exchanger near the zinc

i noted some corrosion around the zinc. Is it due for replacement?

View attachment 161381

You have to remove the brass plug to check. Can’t tell by the outside. Go to www.boatzincs.com and look for “engine zincs” to match it up.

 

[High Wire]

“Auto Air Bleed”. It’s a hose.

 

[paulga]

Did you find that manual in the forum resource section? If not go ahead and add it.

the resource already have it

 

[paulga]

“Auto Air Bleed”. It’s a hose.

This is a simplified plot of the fresh water circuit on page A21 of the manual. The t stat should be where the yellow cross is. When the water temp is low and the t stat is closed, how does the fresh water complete the loop?

 

[paulga]

I detest the cheap, poorly coated, steel winged petcocks that the OP originally showed. Particularly if installed on the top of a heat exchanger, pointing up!

As I said I would change the whole thing and install a steel elbow, a few hose barbs, a SS ball valve and a couple of feet of hose and avoid an Old Faithful coolant event in my ER.

If you are adamant on using a brass vent valve, this one at about the same price is made by a reputable manufacturer, is rated for 150 PSI, has provision for a hose connection, and turns the output 90º so your ability to control the flow is a lot easier. I would just not install the drain hose unless you are actually opening the valve.

Amazon.com

On my Cats, the coolant passage venting is similar to what appears to be shown on the 135, upthread. All pipe threaded fittings that were wound into the heat exchanger, air separator housing and turbo housing jacket are steel. So are the JIC hose fittings.

The fitting in your link has 1/4" threads. The petcock in the westerbeke t stat housing is /1/8" npt. A search of parker 1/8 drain cock gives me this fitting. Same as original one. 1/8 drain cock does not come with a hose stub.

 

[Nick F]

The fitting in your link has 1/4" threads. The petcock in the westerbeke t stat housing is /1/8" npt. A search of parker 1/8 drain cock gives me this fitting. Same as original one. 1/8 drain cock does not come with a hose stub.

Paulga - why do you want a hose barb on the valve? Are you looking for:

1 a valve to purge air from the sytem?
or
2 a valve to drain the water from the system? (in the location you showed in post #10?)

Note: These small "petcock" valves have a very restricted opening. They are good for letting out some air but NOT GOOD for flowing a larger volume of liquid coolant. If used for the latter it will take a long time and there is a high chance of bits of solids getting stuck in the small opening of the valve.
Furthermore, even if this style of valve had a hose connection you should know that this valve has no "stem seal" and liquid would simultaneously dribble out around the threaded stem.

If you do want a drain valve, I recommend a brass (or SS) ball valve, connected to the block by a steel (or SS) nipple. Cut the valve handle short to avoid accidental opening.

 

[Bmarler]

This is a simplified plot of the fresh water circuit on page A21 of the manual. The t stat should be where the yellow cross is. When the water temp is low and the t stat is closed, how does the fresh water complete the loop?

View attachment 161510

If it weren’t for the exhaust manifold needing cooled, it wouldn’t matter if there was no flow with the thermostat closed.
But since it’s a jacketed manifold there needs to be a minimum flow at all times.
There’s a thermostat bypass circuit that passes a small amount of coolant through with the thermostat closed. Usually the bypass circuit will be sufficient cooling at low rpm’s if the thermostat gets stuck closed.

 

[paulga]

Paulga - why do you want a hose barb on the valve? Are you looking for:

1 a valve to purge air from the sytem?
or
2 a valve to drain the water from the system? (in the location you showed in post #10?)

Note: These small "petcock" valves have a very restricted opening. They are good for letting out some air but NOT GOOD for flowing a larger volume of liquid coolant. If used for the latter it will take a long time and there is a high chance of bits of solids getting stuck in the small opening of the valve.
Furthermore, even if this style of valve had a hose connection you should know that this valve has no "stem seal" and liquid would simultaneously dribble out around the threaded stem.

If you do want a drain valve, I recommend a brass (or SS) ball valve, connected to the block by a steel (or SS) nipple. Cut the valve handle short to avoid accidental opening.

Something like this would work
Is this available in steel?

 

[Nick F]

Something like this would work
Is this available in steel?

View attachment 161516

Sorry - you did not answer the question. Paulga, it is difficult to know what you are trying to do.

 

[paulga]

Paulga - why do you want a hose barb on the valve? Are you looking for:

1 a valve to purge air from the sytem?
or
2 a valve to drain the water from the system? (in the location you showed in post #10?)

Note: These small "petcock" valves have a very restricted opening. They are good for letting out some air but NOT GOOD for flowing a larger volume of liquid coolant. If used for the latter it will take a long time and there is a high chance of bits of solids getting stuck in the small opening of the valve.
Furthermore, even if this style of valve had a hose connection you should know that this valve has no "stem seal" and liquid would simultaneously dribble out around the threaded stem.

If you do want a drain valve, I recommend a brass (or SS) ball valve, connected to the block by a steel (or SS) nipple. Cut the valve handle short to avoid accidental opening.

I want to use 2 a drain valve to replace the existing petcock on the t stat housing of the wb Genny, shown in post #1. A drain valve is preferred as it should also purge air.

 

[Nick F]

I want to use 2 a drain valve to replace the existing petcock on the t stat housing of the wb Genny, shown in post #1. A drain valve is preferred as it should also purge air.

OK - understood. However, in this position ( on the thermostat housing) it would only be useful for bleeding air out of that part of the circuit and not for draining the system. Do you need a hose connected when bleeding air?

 

[Bmarler]

Here’s a 90 degree valve with a hose nipple in steel:

8336 Fuel Tank Petcock 1/8" NPT Thread

1/8" NPT thread, steel with round knob

cometkartsales.com

 

[paulga]

OK - understood. However, in this position ( on the thermostat housing) it would only be useful for bleeding air out of that part of the circuit and not for draining the system. Do you need a hose connected when bleeding air?

Thanks.
With the hose connection, maybe a transfer pump can be connected. Since it's only for air out, hose connection is not necessary.

 

[paulga]

You are discouraged to use force or tools to operate these "pissy little" petcocks because inside, the mating surfaces that affect the seal are quite delicate. It also helps if it is well lubricated and you know how to turn it on.

Now, getting your mind out of the gutter, to determine if it's the hose or the drain plug on the heat exchanger that is leaking, clean and dry everything in the vicinity, then using some colored shop towels (Blue or Brown work well) and a twist tie, wrap a 1/2"+/- wide piece around the fitting that has the female threads in it and twist tie it on. Be careful to ensure that there is no contact between the towel and coolant that would leak from the plug itself. Wait and see if it gets wet. The Blue or Brown towels will darken significantly when wet.

My guess it will not get wet and therefore the leak is at the plug.

Let us know your findings.

The leak is slow, I wrapped it but was not observe anything in 30 minutes.

The leak might be from this large coolant hose as I saw some weeping at the connection. So I tightened the clamp a bit.

 

[paulga]

Keep in mind that in order for a zinc to protect anything it must make electrical
contact with it. I would either use nothing and check/clean/replace as needed, or
a metal based anti-seize compound that promotes a decent electrical connection.

I removed the zinc last night. It was so soft as to be easily shaved off when I tried to clean it using a wire brush. I was able to pinch it.
Is the zinc supposed to be soft?

 

[High Wire]

Time to change it before it breaks off and causes trouble.