Wet Exhaust - Is This Mixing Elbow Right?

[Aussie Monty]

Greetings All,

A silly question in a way - but better looking a fool here than later!

I am fitting a wet exhaust system to my Ford Lehman 2712e - it used to be dry. I am using Vetus parts and am being guided by their diagram - see images.

I bought a mixing elbow for the UK - and need to check if it is right - see images as well. It needs to hang off the back of my Bowman Water Cooled Exhaust Manifold. I thought it might be a bit more engineered than this - so it just pumps the water in and exhaust pressure does the rest?

The silly question - is there a risk ANY water may suck back into the head?...or worse?...during shutdown or cranking?

[IMG][/IMG]

[Sailmonkey]

That's an awful mixing elbow. I wouldn't install it on my engine.

The ideal mixing elbow prevents running water from flowing into the engine without the engine running (until the water lift and exhaust hose is full).

This piece does not!

Our mixing elbow is quite simply made of stainless schedule 80 pipe on the dry side that forms a riser, then makes a uturn at the top. The downhill side is simply a bronze T to feed water into the exhaust. But because water would need to travel uphill to get to the engine it's perfectly safe.

Here's a cutaway of a small engine mixing elbow I yanked off the inter webs. Notice water would need to flow uphil to go back into the engine

[Aussie Monty]

Thanks Sailmonkey,

This was my fear - although my research revealed this elbow from Bomac in Georgia and it appears not to dissimilar. Unless the water in route is jacketed down or the like?

[IMG][/IMG]

[Sailmonkey]

Your photo isn't showing up. But usually those straight type of mixing elbows are concentric pipes that join the water and exhaust at the furthest downhill section of the elbow (where the hose connects).

[model 10]

I'm not seeing the problem, it looks like a good part to me. The passages in that cut away elbow elbow look like they would clog up with salt. A proper sized waterlift should not flood the engine unless you have some really nasty following seas.

[Aussie Monty]

TAD Diesel in the US do this one....how is it different?

[IMG][/IMG]

RM

[Sailmonkey]

Originally Posted by Guy

I'm not seeing the problem, it looks like a good part to me. The passages in that cut away elbow elbow look like they would clog up with salt. A proper sized waterlift should not flood the engine unless you have some really nasty following seas.

You don't see a way for water to just drain back into the engine?

[Sailmonkey]

Originally Posted by Aussie Monty

TAD Diesel in the US do this one....how is it different?

[IMG][/IMG]

RM

I can't see the image

[Aussie Monty]

Not sure what I am doing wrong with image SailMonkey. Your concerns, shared by me, prevent me from committing to the use of this elbow.

A stupid question would be - why are they sold?

Scroll towards the end of the TAD Diesel web page and you will see samples that are not dissimilar to mine BUT, one does not get to look inside. Funnily enough, the main reason I bought the one I have was to see how it works...to look inside. Not a good way to spend funds but, useful when one seeks to develop an understanding without making costly errors.

Perkins Exhaust Elbows | Perkins Flanges | Perkins Engine Parts | Perkins Diesel Parts

Perkins Exhaust Elbows | Perkins Flanges | Perkins Engine Parts | Perkins Diesel Parts

Regards

Richard

[Wotname]

I'm with Guy here; I can't see what is wrong with the the water injection port in your OP - assuming it is installed correctly. BTW, I wouldn't call it an elbow.

I'm not familiar with your Bowman Water Cooled Exhaust Manifold but clearly the mixing port has to installed below (and reasonably well below) the height of your exhaust valves. if your manifold doesn't allow for this, then maybe a custom riser (or elbow) has to inserted between the manifold and this injection port. This would allow the injection port to be at a similar height to the exhaust valves.

The rest of the wet exhaust design still has to be kosher - as per the Vetus drawing etc.

IMO.

[Sailmonkey]

Originally Posted by Wotname

I'm with Guy here; I can't see what is wrong with the the water injection port in your OP - assuming it is installed correctly. BTW, I wouldn't call it an elbow.

I'm not familiar with your Bowman Water Cooled Exhaust Manifold but clearly the mixing port has to installed below (and reasonably well below) the height of your exhaust valves. if your manifold doesn't allow for this, then maybe a custom riser (or elbow) has to inserted between the manifold and this injection port. This would allow the injection port to be at a similar height to the exhaust valves.

The rest of the wet exhaust design still has to be kosher - as per the Vetus drawing etc.

IMO.

The problem with the mixer as pictured above is that the flange attaches to the manifold, there is little to no rise/drop from the injection point to the manifold. No problem when the engine is running, potentially huge problem when the engine shuts down and the seawater line drains.

The below image shows the concentric pipes that prevent water from running into the engine.

[Wotname]

Originally Posted by Sailmonkey

The problem with the mixer as pictured above is that the flange attaches to the manifold, there is little to no rise/drop from the injection point to the manifold. No problem when the engine is running, potentially huge problem when the engine shuts down and the seawater line drains.

Perhaps you are more familiar with the OP's manifold than I am but you will note that I qualified the concept with "installed below (and reasonably well below) the height of your exhaust valves". This can be achieved with a short dropper between the manifold and the fitting if there is enough vertical space. If not, then a gooseneck can be inserted between the fitting and the manifold. There is no requirement that the fitting must be attached directly to the manifold.

[Sailmonkey]

Originally Posted by Wotname

Perhaps you are more familiar with the OP's manifold than I am but you will note that I qualified the concept with "installed below (and reasonably well below) the height of your exhaust valves". This can be achieved with a short dropper between the manifold and the fitting if there is enough vertical space. If not, then a gooseneck can be inserted between the fitting and the manifold. There is no requirement that the fitting must be attached directly to the manifold.

You are correct, a separation of the mixer from the manifold via a drop or a riser with the mixer on the downhill side can work.

[model 10]

Originally Posted by Sailmonkey

You don't see a way for water to just drain back into the engine?

The whole system is under water. As long as the flow is down hill to the water lift like it's supposed to be, don't see the problem . And, a proper sized water lift does not fill with water in normal operation.

[Sailmonkey]

Originally Posted by Guy

The whole system is under water. As long as the flow is down hill to the water lift like it's supposed to be, don't see the problem . And, a proper sized water lift does not fill with water in normal operation.

The pictured mixing elbow has little to no downhill run between the manifold flange and the seawater injection point!!