Buhk exhaust elbow

skipper_stu said:
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!
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The issue is that the OP is trying to build a really cheap exhaust elbow from standard plumbing parts which will probably cost him £30 or something.

Once you start using proper marine exhaust elbow components the costs will escalate very rapidly. :ambivalence:

Richard
 
RichardS said:
The issue is that the OP is trying to build a really cheap exhaust elbow from standard plumbing parts which will probably cost him £30 or something.

Once you start using proper marine exhaust elbow components the costs will escalate very rapidly. :ambivalence:

Richard
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The elbow he has made or £30 or so looks pretty close to what its trying to achieve, if there isn't a separator inside the original I see no reason why it wouldn't work.
 
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RichardS said:
The issue is that the OP is trying to build a really cheap exhaust elbow from standard plumbing parts which will probably cost him £30 or something.

Once you start using proper marine exhaust elbow components the costs will escalate very rapidly. :ambivalence:

Richard
Click to expand...
Si
 
paulieraw said:
The elbow he has made or £30 or so looks pretty close to what its trying to achieve, if there isn't a separator inside the original I see no reason why it wouldn't work.
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Sadly once I'd gotten the old one of the flange it became apparent that the threads are subtly different and wasn't going to work. The pitch of the thread is the same but they must have slightly different face angle on the thread . Got me money back and have now ordered the £150 real thing...
 
Isn't there a possibility of water back flushing into the engine manifold?

Yes of course! The better (and the cheaper) solution is the 316 steel exhaust elbow.

The function of the internal sleeve of salt water cannot be neglected.

Best winds!
 
Yes - I have a home made exhaust elbow on my DV20. Constructed more or less as you show, except I have a 45 deg bend for the cooling water inlet. This gives a better angle for the pipework from the anti-syphon valve. I am on my second in 13 years - although the first was still OK when I replaced it. Never any trouble with water flooding the cylinders. The malleable iron bends have a tapered thread, I believe, whereas the exhaust flange fitting on the motor has straight threads. I just tightened them up as hard as I could with a smear of Boss-white.
 
Xenofonte said:
Isn't there a possibility of water back flushing into the engine manifold?

Yes of course! The better (and the cheaper) solution is the 316 steel exhaust elbow.

The function of the internal sleeve of salt water cannot be neglected.

Best winds!
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I think that the function of the internal pipe, in those designs that have them, is primarily to reduce the length of bare metal pipe that is effectively at exhaust temperature; ie. very hot. On a plain pipe, provided the water connection is well below the exhaust port, water ingress will not occur. This is how the Beta design works, and others no doubt.
The penalties of an internal pipe will be to increase the cost of manufacture and also allow the possibility of unseen corrosion failure with attendant water ingress into the engine, well documented on this forum over the years.
 
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neil_s said:
Yes - I have a home made exhaust elbow on my DV20. Constructed more or less as you show, except I have a 45 deg bend for the cooling water inlet. This gives a better angle for the pipework from the anti-syphon valve. I am on my second in 13 years - although the first was still OK when I replaced it. Never any trouble with water flooding the cylinders. The malleable iron bends have a tapered thread, I believe, whereas the exhaust flange fitting on the motor has straight threads. I just tightened them up as hard as I could with a smear of Boss-white.
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blast well maybe next time....
 
paulieraw said:
The elbow he has made or £30 or so looks pretty close to what its trying to achieve, if there isn't a separator inside the original I see no reason why it wouldn't work.
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It DOES work if you fit the components in the correct sequence i.e. 45° elbow (screws onto original manifold flange) then the "T" with nipple and elbow already fitted and finally the adapter to take the flexi exhaust hose. HWMO made one up for a DV24 a few years ago and it is still going strong. IIRC it set us back around £22 in those days.
The original poster arranged the components in the wrong sequence.
 
Someone mentioned a stainless steel one. A few year ago I was talking to the Buhk dealer who services my engine about the elbows he said he had made some up in Stainless and tried them out and the life span was no better that the steel so he now stays with the Buhk original.

David MH
 
PowerSlapper said:
It DOES work if you fit the components in the correct sequence i.e. 45° elbow (screws onto original manifold flange) then the "T" with nipple and elbow already fitted and finally the adapter to take the flexi exhaust hose. HWMO made one up for a DV24 a few years ago and it is still going strong. IIRC it set us back around £22 in those days.
The original poster arranged the components in the wrong sequence.
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My picture is exactly what you describe...
 
I have welded them up using weld L's
Practical Boat Owner said the exhaust should rise and fall 16 inches before injecting any water. Not a bad idea, given the number of engines screwed up by exhaust water. I have been using dry exhaust for decades, eliminating a lot of problems.That lets you use stainless for all exhaust pipes and fittings.
 
The hose-tail looks like it's attached to the reducing tee by welding.
The female threads will generally be parallel, taper for male.
Nero Stainless carry good stocks of all sorts for postage or pick-up from the Birmingham area. You would need the 150 lb. range.
Good prices and helpful.
 
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HI
a couple of add on's (hose-tail looks like it's attached to the reducing tee by welding) yes to suit ex hose without more adapters more pics showing one made up for DV10 without need for welding ,

https://flic.kr/s/aHsmcLj4PC

I have got the parts via local Hydraulics supply he does'nt carry stainless stock usually but is happy with counter ordering to to pass on most of his large trade discount there is every chance he orders from Nero Stainless but I dont know but iirc some online supplers were over the top , so if you have a local suppler take a copy of pics with you it helps for them to understand what you need & as i found are very helpful
 

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