exhaust riser options

[milesbernie]

Hello all,

I had a new volvo D1-20 engine installed in my Halmatic 30 last year. After 40 hours the engine siezed due to water ingress. We managed to free the engine by hand and I'm hopeful that the engine is still ok as the compression is good and it still fires and runs well.

The engine is below the water line and the waterlock the installers fitted was only about 4” below the exhaust elbow (prop shaft limits a greater drop). I’m weighing the options – riser vs some form of manual exhaust shut off to prevent this happening again.

Nigel Calder talks about the use of galvanised pipe for a riser fabrication in his book. I can’t help feel that this will corrode rapidly. I’ve looked at stainless options but the price of fabrication seems excessive.|

A cheaper option is a simple shut off ball valve fitted after the exhaust elbow (as per SunStone in last monthe PBO). This would be a bit of a pain to shut down but I like the price. There are electrically operated ball valves available too – so as long as a manual override was possible this could be a simpler approach.

I’d really appreciate your thoughts on the two options and also it’d be good to hear of anyone that you could recommend for fabrication of a riser.

We are heading off on a N. Atlantic circuit in July so I need to get this sorted rather rapidly!

Fair winds

 

[webcraft]

Did you have a gooseneck or loop of pipe between the transom outlet and the waterlock? Or is this what you mean by a riser?

- Nick

 

[rogerthebodger]

I made my own rider / gooseneck out of stainless steel pipe, ss weld elbows and threaded nipple. I also included a ss ball valve as my exhaust exits on the side of my yacht and not the transom.

This I did for both my main engine and a small water cooled diesel generator. I welded up using stick arc welder which is ok for this (I also have TIG welding available for use on thin materal)

I am also making some electric actuaters using windscreen wiper motors, relays and micro switches for right angle movement. I will be including a disconnect latch so the valve can be moved manually if electrics fail

You will also need to consider that the volume of the waterlock needs to be big enough to hold the volume of water in the exhaust pipe from the engine to the waterlock and from the waterlock to the exhaust outlet else water will find ite way into the engine

 

[salamicollie]

If you mean a high rise exhaust system - try talking to asap-supplies (0845 1300 870) - They do a set of universal exhaust outlets - manifolds and bends you can build into a high rise exhaust - the water mixer is stainless and the pipe bends can be stainless/black steel, bronze etc.. The only issue may be the size and accessability of your exhaust port and fixing centres and whether one of the standard adaptors fits.

 

[milesbernie]

Thanks - yes I spoke to asap supplies. The vovlo d1-20 has a air filter in a position the forces the exaust elbow to turn to port immediately on exit. This means it's not possible to use asap's kit. Shame as this would have done nicely!
Could you recomend anyone else who could fabricate?
I'm based on the east coast but am willing to travel and have a detailed design including all dimensions.
Thanks again

 

[Will_M]

Volvo Penta D1-13, D1-20, D1-30, D2-40 high rise exhaust elbow, pn. 3884165

As a point of interest, who did the installation, sounds as though insufficient consideration was paid to the exhaust system.

 

[milesbernie]

Thanks - problem is that the part you mention is difficult to get hold of. Volvo have told me I can order it but not as easy as not in stoick anywhere. Also this part raises the elbox 4 inches only. I need around 7 inches of extra height.

 

[novice04]

I changed the dry to wet exhaust system on my old MD3B. Encountered the same problem in the process - couldn't get the waterlock low enough. Went to a (sympathetic) car-exhaust guy and had made a riser - welded SS tubing, 18 cm higher than original exhaust elbow, almost perfect U (reversed) shape. Also had a strange angle issue. Then I took this piece to a professional welder who carefully re-welded all the joints again (plus a piece where cooling water enters the system on the downward slope). Then a flex. tube down to the waterlock, followed by a tube rising to a large muffler which is at the highest spot (under the aft deck) and down to exhaust thru-hull (no room for gooseneck). Plus an anti-syphon valve. Plus some thermo isolation band on the U (before the water entrance).
You might want to check the Vetus catalogue for diagram.
Works perfectly for 2. season now!
Cost: some 20 quid, 3 days running arround and 1 question posted on this Forum!
Original Volvo part: 120 quid + 4 weeks for delivery!
If it ever fails, I'll just do it again.
Good luck,
Nenad

 

[salamicollie]

Can't suggest a stainless steel fab as I drew blank trying to sort mine out (price of a Yanmar exhaust elbow is quite steep) but I guess the exhaust is 45 or 50mm diameter - you may be able to get a standard radius pipe bend or stainless radius tube and get a plate welded to it so that you clear the airfilter - from there use pipe fittings and the asap mixer?

The problem is that the marine fabs don't usually have tooling to custom bend 2 inch tube.... and angled bemds will create not spots.