Bukh Exhaust

[nordic_ranger]

Has anybody made their own exhaust system for a Bukh engine ?( DV10 )
It seems to me to be made of cast iron pipeing and I was wondering if screwed and threaded cast iron heating pipe as found in old central heating systems could be used if properly joined together.

Jim.

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[jerryat]

Hi Nordic Ranger!

I got fed up at the price for new cast iron exhaust elbows for my Bukh too, and did two things:

1. The last one I bought, about nine years ago, I first degreased internally very thoroughly, then coated with 5-6 coats of epoxy paint. I used some International Interprotect I had left over from hull painting. Since then we've used the boat/engine for over 25K miles and I've just replaced it during my major refit. About every two years I'd removed the elbow, wiped it clean, and added a coat or two. This method extended its life dramatically.

2. At the same time as I bought the above, I was so p****d off at the cost, I enquired of a small local marine metal worker, the cost of producing one in stainless steel. He quoted, and produced a superb copy in very heavy walled s/s pipe (about 4mm) that was a perfect fit for £25.00. That is the one that I have just fitted to my B 20. If you try this method, make sure that the wall thickness is similar to mine as even s/s will eventually corrode in this situation.

I made sure that the four bolts that hold the elbow to the manifold are virtually isolated form the elbow to reduce/eliminate the risk of additional corrosion and intend changing the engine anode at least twice a year just in case. I make my own anodes, so it costs very little. The elbow works perfectly.

Hope this helps.

Good sailing!

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[nordic_ranger]

Many thanks, I would never have thought of epoxy coating but that is a great idea. I got only three years from my present one and baulked at the cost of a replacement.
I will also ask my local metal fabrication company what cost to make a stainless steel one.

Jim.

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[jerryat]

Hi Jim!

You're very welcome. Just a small but important additional thing; if you do epoxy paint (and it is extremely effective) do make sure you work the paint into every 'nook and cranny', especially the water injection point as this, and the area of elbow wall directly opposite it, is subject to the worst effects of coking/corrosion. I used a small 'artist' type brush at this point so that I could paint right up to the threads. It's fiddley, but well worth taking particular care over. Incidentally, you will find after about four-five years (though check more regularly) soot/coke deposits will start to build up. VERY careful use of a screwdriver will remove this with little damage to the epoxy. You can then degrease and paint again!

My 9 year old elbow was probably good for another year at least, but as I'd stripped the engine down to replace pistons, liners, rings etc etc, I thought I'd put the nice new s/s elbow on the nice, shiney painted motor. Whole thing is back in the boat and looks fantastic.

Personally, and if you haven't yet bought a new cast iron one, I'd shop around as you suggest to check out prices for a s/s version. I just gave them the cast iron one and said 'Match that if you can!' Down here in Plymouth, I reckon they saw it as a challenge, though do remember that my price was nine years ago, so you may well pay a lot more now. Still the best way forward though, especially if, like me, you are off cruising again soon.

Cheers

Jerry

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