Buhk exhaust elbow

[NigelBirch]

I found a thread about making an exhaust elbow using standard pipe fittings:

Blk Mall 45 deg M&F elbow-156 1 1/2 inch qty 1
Blk H/W barrel nipple 1 1/2 inch qty 1
Blk Mall sq tee - 161 1 1/2 x 1/2 inch qty 1
Blk Mall 45 deg M&F elbow - 156 1/2 inch qty 1
1/2 inch male bspt x 1/2 inch brass hose tail qty 1

Having bought the bits for £31 and putting it together I now have doubts. Isn't there a possibility of water back flushing into the engine manifold?



Be very interested to hear from anyone that's done this.

atb

Nigel

 

[richardabeattie]

Have you fitted the internal sleeve to direct the water in the direction of the exhaust gas flow?

 

[NigelBirch]

No there was no mention of an internal sleeve.

 

[RichardS]

I don't know how you would ever find an internal sleeve as a standard pipe fitting anyway.

Whether there is a danger of flooding the exhaust manifold/header will depend upon the mounting angle of the exhaust elbow. If the water injection point is as far below the exhaust manifold/flange as the elbow will allow then I would be very happy with it. If the injection point is approaching towards level with the bottom of the manifold I would be concerned and would consider an internal baffle/sleeve being welded or JB-Welded on. If the injection point is level with or above the bottom of the manifold then I wouldn't proceed.

Richard

 

[NigelBirch]

That makes sense. I might need to get another piece to get the water inlet lower.....

 

[paulieraw]

No there was no mention of an internal sleeve.

I have just had to buy a exhaust elbow for a Petter mini twin, very similar, there is a sleeve built in to prevent water from going back into the engine, it mixes in the exhaust pipe further down.

 

[Heckler]

I don't know how you would ever find an internal sleeve as a standard pipe fitting anyway.

Whether there is a danger of flooding the exhaust manifold/header will depend upon the mounting angle of the exhaust elbow. If the water injection point is as far below the exhaust manifold/flange as the elbow will allow then I would be very happy with it. If the injection point is approaching towards level with the bottom of the manifold I would be concerned and would consider an internal baffle/sleeve being welded or JB-Welded on. If the injection point is level with or above the bottom of the manifold then I wouldn't proceed.

Richard

https://www.asap-supplies.com/seaflow-engine-exhaust-outlet-spray-head-2188463 this is what I used, they have loads of sizes threaded. In the OPs case perhaps an internal copper pipe inside the threaded T?

 

[Poignard]

https://www.asap-supplies.com/seaflow-engine-exhaust-outlet-spray-head-2188463 this is what I used, they have loads of sizes threaded. In the OPs case perhaps an internal copper pipe inside the threaded T?

If he's going to spend that sort of money he'd be better off buying the proper BUKH part, which is cheaper and includes a made up water injection hose.

 

[Mistroma]

I have just had to buy a exhaust elbow for a Petter mini twin, very similar, there is a sleeve built in to prevent water from going back into the engine, it mixes in the exhaust pipe further down.

Same with my Yanmar. However, the DV20 just has an injection hole in the side of the pipe and no internal sleeve. No internal copper parts just a casting with a smaller pipe on the side.

I once made up something similar to OP's bodge when I was stuck a few hundred miles from home. No easy access to BUKH spares and bought bits from industrial plumbing place. It was fine for the rest of the season.

I painted inside the new part with some high temp. paint with interlocking glass fibres. No idea what it was but that elbow lasted for many years. I think I only changed it once more over the next 22 years.

 

[paulieraw]

If he's going to spend that sort of money he'd be better off buying the proper BUKH part, which is cheaper and includes a made up water injection hose.

I agree, the proper part is designed with the right level from the engine. The expensive part I bought for my Petter takes the water from the maniold and ensures the correct angles and take of points are correct.
Any backflow into an engine is likely to be pretty bad.

 

[seumask]

Where did you get the parts from, I'm interested in making up the same for my Bukh as a spare. Thank you.

 

[seaangler23]

What's the largest compression type fitting that would go into the t, get a bit of copper pipe stick a bend in it inside the t so it's facing down the exhaust and do up the compression fitting. Would maluable iron not disintegrate pretty quick ?

 

[Poignard]

Here's a photo of the BUKH part, for comparison



Currently priced at £144 plus £6.50 carriage, from T.Norris Ltd via ebay

 

[NigelBirch]

Worsley pipe centre....

 

[NigelBirch]

Here's a photo of the BUKH part, for comparison

View attachment 69839

Currently priced at £144 plus £6.50 carriage, from T.Norris Ltd via ebay

Yep thats what i am replacing. Lasted me 9 years. There is no internal baffle in the buhk part so i think as long as i get the injection point as low as the original it should be fine.

 

[Poignard]

When I bought my boat here BUKH engine had an exhaust system made up of components like you have assembled. It certainly worked fine but corroded through a year after I bought her but unfortunately I have no idea how old it was when it failed. I would have liked to have replaced whichever component it was that failed (I can't remember now which it was) but it was quicker to get one delivered next day from BUKH rather than hunt around a strange town for a supplier of iron pipe fittings.

 

[Heckler]

I agree, the proper part is designed with the right level from the engine. The expensive part I bought for my Petter takes the water from the maniold and ensures the correct angles and take of points are correct.
Any backflow into an engine is likely to be pretty bad.

What the Parsifal doesn't know is that the part for my MD22 was the thick end of £400 before www.parts4engines.com came long. Also my reply was to give a heads up to Richard that threaded lined exhaust elbow components are available. ASAP are very good if you order on a regular basis and do do discounts!

 

[NigelBirch]

I don't think the injection point is too out of whack with the original....

 

[Heckler]

I don't think the injection point is too out of whack with the original....

View attachment 69841

Especially given that the stub it will screw on to will make the inj point further away from the manifold

 

[paulieraw]

Which Parisfal is that then?