question on a shut off valve

[paulga]

This is a petcock on the t stat housing on a Westerbeke genny -- BCD6.0KW. it looks like a pipe plug installed on a bushing with some thread sealant.
Does this valve open and close like a ball value that usually is quarter turn? for comparison, I have attached a picture of a needle valve on a compression fitting

a distributor has confirmed the petcock part number is 11471. But the hex base in the photo of 11471 appears to have a sealed end, instead of a through passage. This is confusing.

 

[WillieC2]

Not a quarter turner. More like if not precisely a ball valve. The sealed end you see is the “ball”, the seal. It opens by turning the handle.

 

[Delta Riverat]

That's an old style radiator drain. Yeah, had one on my 1966 Ford Fairlane. You screw it in to open and the water comes out the hole in the handle.

 

[NoRain]

Not a quarter turner. More like if not precisely a ball valve. The sealed end you see is the “ball”, the seal. It opens by turning the handle.

I think you mean gate valve.

My guess would be it’s to burp the air when you are refilling the coolant.

 

[Delta Riverat]

Yup.

 

[luna]

If you look closely at the threads directly below the wings that you use to open and close this Petcock, you should find them spiralling around the brass shaft in an opposite lay to the threads that are used to thread the Petcock into the T stat housing.
If so, this means that these threads are what is called "left hand threads" and in order to open the valve you need to turn the wings Counter Clockwise (CCW) when viewed from the top. It will take numerous turns to fully open the Petcock. This CCW turn which normally draws a bolt up and out of a threaded hole, in this instance draws the brass shaft down and in towards the T stat housing thereby lowering the plunger that you see closing the bottom of the new, loose Petcock. This opens the Petcock.

Although somewhat counterintuitive, there is good reason to design the petcock this way as by the time you get around to opening this Petcock again it will be corroded and seized shut. Forcing it open by turning it the opposite way than "normal" cannot result in loosening of the threaded connection to the T stat housing as that rotation tightens the T stat connection. Conversely, closing the Petcock which opens the T stat connection needs to be done with an experienced hand. Yours will be fine, just don't use tools.

Do yourself a favour, clean the exposed left hand threads with a fine wire brush and then apply some Neverseize before you turn CCW.

I know nothing about your engine but are you sure that this petcock is intended for this (vent) location?
Seems odd. How often are you to vent?

 

[BruceK]

On a Ford Lehman, you open the manifold petcock when topping up coolant, when coolant appears, it`s full. Never open it when running or air goes in. Be gentle, and keep it lubed. How it works on a Westerbeke genset, I can`t say.

 

[paulga]

If you look closely at the threads directly below the wings that you use to open and close this Petcock, you should find them spiralling around the brass shaft in an opposite lay to the threads that are used to thread the Petcock into the T stat housing.
If so, this means that these threads are what is called "left hand threads" and in order to open the valve you need to turn the wings Counter Clockwise (CCW) when viewed from the top. It will take numerous turns to fully open the Petcock. This CCW turn which normally draws a bolt up and out of a threaded hole, in this instance draws the brass shaft down and in towards the T stat housing thereby lowering the plunger that you see closing the bottom of the new, loose Petcock. This opens the Petcock.

Although somewhat counterintuitive, there is good reason to design the petcock this way as by the time you get around to opening this Petcock again it will be corroded and seized shut. Forcing it open by turning it the opposite way than "normal" cannot result in loosening of the threaded connection to the T stat housing as that rotation tightens the T stat connection. Conversely, closing the Petcock which opens the T stat connection needs to be done with an experienced hand. Yours will be fine, just don't use tools.

Do yourself a favour, clean the exposed left hand threads with a fine wire brush and then apply some Neverseize before you turn CCW.

I know nothing about your engine but are you sure that this petcock is intended for this (vent) location?
Seems odd. How often are you to vent?

the distributor said it "screws in clockwise to open". this means it is right hand threads.
I already tried to turn the valve manually, but it felt jammed. may not be possible to turn it without using a wrench
I will confirm the threads.

 

[BVrolyk]

You may need to replace this if it hasn't been used in a while. It wasn't designed to be opened with a wrench.

For many engines, these valves are to let water out and air in, to aid in draining an engine of all fluids before replacing something like a water pump, or for allowing air to escape when filling the cooling system. Folks used them all over engines back when I was a kid. (I'm 73). EG: You'll find one at the bottom of my '65 Morgan radiator.

I'd strongly suggest not using a wrench until you've soaked everything in something like WD-40 or one of the other penetrating oils for this purpose, and as "Luna" has suggested above, clean that inner set of threads, as that is what is going to go down into the outer bit of the valve and they look quite corroded. If you force it, the threads will wear and may not work at all.

 

[paulga]

On a Ford Lehman, you open the manifold petcock when topping up coolant, when coolant appears, it`s full. Never open it when running or air goes in. Be gentle, and keep it lubed. How it works on a Westerbeke genset, I can`t say.

is this fitting on the manifold where the block side drain cock should be?
this engine has a 1/4" pipe plug here instead of a petcock.

FL135 engine block portside:

On a Westerbeke generator, the manual refers to the coolant reservoir as the "exhaust manifold", and the fresh water coolant fill as the "pressure cap". Here the fresh water air bleed is the petcock on the t stat housing in post 1.

 

[Nick F]

the distributor said it "screws in clockwise to open". this means it is right hand threads.
I already tried to turn the valve manually, but it felt jammed. may not be possible to turn it without using a wrench
I will confirm the threads.

Replace it! It is a $5 item. BTW it definitely CLOSES when screwed clockwise!

 

[luna]

You can determine which way it turns (to open it, you want to turn it into the T stat housing) by looking at the threads.

If it was me, as those style of petcocks are a pain, I would replace it with a steel 90º elbow & a 1/4" hose barb, then run a short section of hose to a Stainless Steel 1/4" ball valve that I would mount on the engine's lifting ring or some other high location.

That way I can easily open the valve 3 years from now when I want to change coolant and then using another short piece of hose vent the system into a Coke bottle when I refill. No clean up required.

 

[SteveK]

Replace it! It is a $5 item. BTW it definitely CLOSES when screwed clockwise!

Likely why it is hard to move, too many attempts to OPEN CCW.
IT closes CCW

The Lehman aslo has this on top of the exhaust manifold to burp air from the coolant

 

[paulga]

You can determine which way it turns (to open it, you want to turn it into the T stat housing) by looking at the threads.

If it was me, as those style of petcocks are a pain, I would replace it with a steel 90º elbow & a 1/4" hose barb, then run a short section of hose to a Stainless Steel 1/4" ball valve that I would mount on the engine's lifting ring or some other high location.

That way I can easily open the valve 3 years from now when I want to change coolant and then using another short piece of hose vent the system into a Coke bottle when I refill. No clean up required.

does 316 stainless steel 90 degree elbow work better than a brass one?

 

[Greg QS]

In that application steel is fine. The inside is protected by the coolant. the exterior you paint. Or use a galvanized part. Remember the whole block is steel anyway. If the manufacture were to add that modification they would have used steel. Steel is more robust than the brass. I have used small steel fittings for exactly what you are doing and for moving and adding ports for oil sensors on my gensets.
That plug you are pulling out is steel. The oil sender is steel.

 

[Bmarler]

I like the little 1/4 turn petcocks like this one: Petcock

 

[paulga]

I like the little 1/4 turn petcocks like this one: Petcock

this fitting is cute.

 

[luna]

Because diesel engines vibrate quite a bit, anything directly connected by way of pipe threads to the engine is best made from steel. This elbow or petcock is not the place to use brass or stainless.

 

[paulga]

In that application steel is fine. The inside is protected by the coolant. the exterior you paint. Or use a galvanized part. Remember the whole block is steel anyway. If the manufacture were to add that modification they would have used steel. Steel is more robust than the brass. I have used small steel fittings for exactly what you are doing and for moving and adding ports for oil sensors on my gensets.
That plug you are pulling out is steel. The oil sender is steel.

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?

 

[Nick F]

Because diesel engines vibrate quite a bit, anything directly connected by way of pipe threads to the engine is best made from steel. This elbow or petcock is not the place to use brass or stainless.

In general I agree with this but in the case of this purge valve it has nothing connected to it which might add "leverage" so, in this case, I dont think it is a problem to use this brass valve.

 

[luna]

This is about what you would be looking for.

Amazon.com

Here is another one which is simply built to a higher specification and has better quality threads.

Amazon.com

Yes it takes a 1/4" barbed fitting with female threads instead of male, big deal.

Both of these are designed for use in a hydraulic system. You don't need the pressure rating as your coolant system runs at maybe 15 PSI. What you need is something to withstand the shake, rattle and roll of the diesel.

 

[Bmarler]

Because diesel engines vibrate quite a bit, anything directly connected by way of pipe threads to the engine is best made from steel. This elbow or petcock is not the place to use brass or stainless.

There’s absolutely no issue using those little brass petcocks for air purge valves. They were good enough for the Navy, they’re good enough for me.
Way more reliable than those cheap ones that nobody knows what direction to turn them because they make them both ways.

 

[paulga]

Likely why it is hard to move, too many attempts to OPEN CCW.
IT closes CCW

The Lehman aslo has this on top of the exhaust manifold to burp air from the coolant

This is the overview of the fl135 exhaust manifold.

Which fitting is the petcock on the top? Per the manual, there is a coolant drain port at the "rear aft of the exhaust manifold". Could you mark both fittings in the photo?

 

[SteveK]

well maybe the 135 improved on the 120 It would have gone where that hose/pipe comes out of manifold and goes into expansion tank.

 

[luna]

There’s absolutely no issue using those little brass petcocks for air purge valves. They were good enough for the Navy, they’re good enough for me.
Way more reliable than those cheap ones that nobody knows what direction to turn them because they make them both ways.

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.

https://www.amazon.com/Parker-Hannifin-Drain-Cock-Hose/dp/B01BYLXUI2?th=1#

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.

 

[Bmarler]

Like most things, there are plenty of acceptable ways to do this thing. I’m not adamant about brass, it’s just that it’s easy to locate. painted steel is also fine on an engine, and a terrific choice.
I too, dislike the wing petcocks. They’re just too fragile.

 

[paulga]

well maybe the 135 improved on the 120 It would have gone where that hose/pipe comes out of manifold and goes into expansion tank.
View attachment 161283

there is not a valve in that area.

 

[paulga]

You can determine which way it turns (to open it, you want to turn it into the T stat housing) by looking at the threads.

If it was me, as those style of petcocks are a pain, I would replace it with a steel 90º elbow & a 1/4" hose barb, then run a short section of hose to a Stainless Steel 1/4" ball valve that I would mount on the engine's lifting ring or some other high location.

That way I can easily open the valve 3 years from now when I want to change coolant and then using another short piece of hose vent the system into a Coke bottle when I refill. No clean up required.

the upper thread is left hand. i was able to rotate it lefty by hand. it's still working, so no need to change it.

 

[paulga]

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?

 

[Nick F]

there is not a valve in that area.

View attachment 161379

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.