BUKH Exhaust - Urgent

[steve48]

Help
Just started holidays and arrived in Fecamp (the day before the 80 boats on the Royal Escape from Brighton).
Having a routine check over, I noticed a 3 inch rust line on the outer surface of the exhaust elbow of my 1985 raw water cooled BUKH 20 HP. Positive it was not there a month ago! The elbow is 4 years old – I normally have this problem after 5). Local engineers do not stock parts and say it is a lengthy process to obtain one.
I have some American self amalgamating “Rescue Tape” bought at a boat show and claiming to 'seal anything' and is able to withstand temps up to 260 deg Celcius, can cope with 700psi and resists salt water. Being a wet exhaust, this is OK?
Anyone have any ideas as to its effectiveness?
If OK, plan to get our friends in Poole to send an elbow out to Cherbourg and fix it there.
All comments welcome, along with any other bodge suggestions.
Thanks in advance
Steve

 

[greenalien]

I got fed up with replacing these expensive items on my DV20. so I made a replacement from a piece of galvanised scaffolding pipe and a piece of 1/4" sheet steel for the flange. It doesn't look very pretty, but it's still going strong after 10 years!
There are also stainless steel replacement exhaust bends available at a similar price to the Bukh originals, and people have also made replacements from standard plumbing fixings - search the threads on here for more details.

 

[chewi]

3" crack still leaves a fair amount of metal , so it has some residual strength, but the crack could propagate so I suggest you reinforce it with a hacked up bean tin and jubilee clips to keep the stress off the crack.

I got an elbow ex stock £140 from Elkins boatyard in Xchurch in Nov 2011


good luck.

 

[chewi]

I got fed up with replacing these expensive items on my DV20. so I made a replacement from a piece of galvanised scaffolding pipe and a piece of 1/4" sheet steel for the flange. It doesn't look very pretty, but it's still going strong after 10 years!
There are also stainless steel replacement exhaust bends available at a similar price to the Bukh originals, and people have also made replacements from standard plumbing fixings - search the threads on here for more details.

mine was a s/s relacement already fitted (DV10) when I bought it in 1998.
I had a recon this winter (2011) and a crack was evident, so I replaced it, but that was 14yrs. There were conflicting views on s/s v galvanised in this application when I read about it, but Elkins said the mirror polishing on my new one was not for pretty, it helps shed the water and acids when the engine is stopped, and prevents corrosion afterwards.

Too early to say if they are right.

 

[Pasarell]

Rescue Tape is remarkable stuff. I used it to repair a leak in my exhaust about 2 years ago and was tempted to leave as a permanent repair it worked so well.

 

[Salty John]

Yes, silicone self fusing compression tape ("rescue" tape) should give a satisfactory temporary repair. You might want to then add a couple of hose clamps to provide some mechanical integrity.

Calder, in his book, shows an elbow repaired with two hose clamps over inner tube rubber and claims it survived for 200 hours running.

 

[Poignard]

Having had one of these break, and remembering the filthy mess left behind, I would take it off and examine very carefully. If I wasn't convinced it would last much longer I would get the nearest garagiste to weld it up. Failing that I would either wait for a new part to arrive or, more probably, sail to Cherbourg and avoid using the engine until I was inside the Petite Rade.

 

[essexboy]

Drill a small hole at each end of the crack to stop the propagation, before repair tape.

 

[cliff]

I got fed up with replacing these expensive items on my DV20. so I made a replacement from a piece of galvanised scaffolding pipe and a piece of 1/4" sheet steel for the flange. It doesn't look very pretty, but it's still going strong after 10 years!
There are also stainless steel replacement exhaust bends available at a similar price to the Bukh originals, and people have also made replacements from standard plumbing fixings - search the threads on here for more details.

http://www.ybw.com/forums/showpost.php?p=770326

 

[VicMallows]

http://www.ybw.com/forums/showpost.php?p=770326

....and if you happen to need a new exhaust bend on the IOW, that incredible ironmonger HURST in Newport has all the bits on the shelf self-service. so you can play around as long as you like making up a suitable fitting.

All the OP needs now is a similar source in Fecamp

 

[boguing]

I fixed one for a friend. It had already been welded, but this was a new crack. Wound a lot of copper wire around it after grinding back to clean metal, then slathered it with epoxy. Still going strong three years later.

 

[steve48]

Hi all, and thanks for your replies.

I have been reliably informed that the exhaust elbow, before the water inlet, can reach 500C. This is where the crack is.

I have ordered a new elbow and flange (don't fancy tryting to unscrew pipe from flange here) from Poole and await delivery.

There are worse places to be stuck than Fecamp.

Thanks again.

Steve

 

[SimonJ]

I got 7 busy years out of my last elbow (but now I am trying SS) by cleaning inside then spraying with v high temp paint before first use. Each year I clean & inspect. This pays off.