Exhaust hose reducer

zoidberg

zoidberg

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I need to reduce the 51mm exhaust hose - from the mixer elbow - to 38mm at the Vetus watertrap inlet. The Vetus shop have recommended and sold me a stepped grey plastic reducer called 'Hose Adapter HA3060'.

Has anyone here had experience of using this product in the above role?

Edit: 40mm, not 38mm. Problem of manipulating a caliper gauge at full stretch and out of sight.
 
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Doesn't this mean you are trying to fit an undersized waterlock muffler to a larger exhaust outlet? I thought it was a bad idea to reduce the exhaust size in such fashion.
 
zoidberg said:
I need to reduce the 51mm exhaust hose - from the mixer elbow - to 38mm at the Vetus watertrap inlet. The Vetus shop have recommended and sold me a stepped grey plastic reducer called 'Hose Adapter HA3060'.

Has anyone here had experience of using this product in the above role?
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Surely just cut off the two largest size steps ( 60 and 57 mm ) and the two smallest steps ( 30 and 32 mm ) and you will be left with a suitable adapter for your two hose sizes.

So short bit of 51mm hose on the elbow, then the adapter and a short bit of 38mm hose to fit the watertrap.. Or am I missing something ?

Personally I would have matched the whole system to the elbow diameter so that there was no size reduction. 51 mm to 38 mm diameter is a heck of a reduction in cross sectional area. Almost halving it!
 
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Yngmar said:
Doesn't this mean you are trying to fit an undersized waterlock muffler to a larger exhaust outlet? I thought it was a bad idea to reduce the exhaust size in such fashion.
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Seems like a bad idea to me as well. If the engine designer specified a 51mm exhaust diameter that's what it should be all the way through.
 
Twisterowner said:
Seems like a bad idea to me as well. If the engine designer specified a 51mm exhaust diameter that's what it should be all the way through.
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This was all debated at some length in another recent thread also started, if memory serves, by zoidberg. The consensus of well-informed participants was that it's OK (within limits, obviously), also suggesting a more elegant way of achieving it. Beta, who I think provided the engine in question, are quite relaxed about such measures, only stating that exhaust back-pressure should not exceed a prescribed value.
 
Hi I also had to reduce my exhaust from 51mm at the elbow to the Vetus muffler (38mm). My easy solution was to have an exhaust hose made by Portmere rubber 51mm one end and 38mm the other end and whatever length you wish.(no adaptor fewer possible leaks). Phone Angela at Portmere she's brilliant.

Jim
 
zoidberg said:
I need to reduce the 51mm exhaust hose - from the mixer elbow - to 38mm at the Vetus watertrap inlet. The Vetus shop have recommended and sold me a stepped grey plastic reducer called 'Hose Adapter HA3060'.

Has anyone here had experience of using this product in the above role?
Click to expand...

Yes I have it on my installation in the hose from the manifold to the waterlock as my existing warterlock has fixed spigots. Up from 40mm (essentially the same as your 38) to 45mm. Works perfectly. It is made of the same material as the waterlock and is made specifically for this application (although it may of course be used elsewhere).
 
I would have thought if a reduction in diameter was necessary it would best to have this after the water-trap, and as close to the exhaust outlet as possible. Cooler there, and less impact on back pressure as a result of (a) shorter length of narrower hose and (b) greater volume before the reduction to absorb the exhaust pulses.
 
LittleSister said:
I would have thought if a reduction in diameter was necessary it would best to have this after the water-trap, and as close to the exhaust outlet as possible. Cooler there, and less impact on back pressure as a result of (a) shorter length of narrower hose and (b) greater volume before the reduction to absorb the exhaust pulses.
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I think the point of the original question was that the exhaust elbow is 51mm while the water lock purchased is only 38mm. Therefore the size reduction has to take place between the two..
 
VicS said:
I think the point of the original question was that the exhaust elbow is 51mm while the water lock purchased is only 38mm. Therefore the size reduction has to take place between the two..
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Has to take place there?! Why?

I thought it obvious that my suggestion involved replacing the water-lock. (A minor cost as part of an an engine replacement project).
 
For those concerned about back-pressure, just a little by way of background: the OP's engine is indeed a Beta which does have a 50mm (as described by Beta) exhaust. But so does every other Beta, up to and including the Beta 60. I suspect a slightly smaller exhaust isn't likely to strangle his Beta 14.
 
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macd said:
For those concerned about back-pressure, just a little by way of background: the OP's engine is indeed a Beta which does have a 50mm (as described by Beta) exhaust. But so does every other Beta, up to and including the Beta 60. I suspect a slightly smaller exhaust isn't likely to strangle his Beta 14.
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And as I pointed out in the original thread, the Nanni version of exactly the same base engine has a 40mm exhaust outlet.

Back pressure is a non issue - the question was about the suitability of the Vetus reducer and the answer is that is what it is made for.
 
Perhaps a clarification is warranted...

The ould boat has an existing exhaust system comprising Vetus 40mm transom outlet, 40mm hose from Vetus Gooseneck, 40mm hose from Vetus LP40 Waterlock with 40mm ports, and 40mm hose to 'old engine 40mm injection bend'.

The old engine has been removed, and replaced with a new Beta 14 unit, which arrived with a 51mm injection bend. That difference was unexpected.

Replacing all the above existing exhaust system would run into several hundred pounds, to say nothing of the hassle involved in drilling a marginally larger hole in the transom, and I'd rather keep what I reasonably can. Clearly, I need new hose from the new 51mm injection bend, so I bought 1.5 metres of posh Vetus rubber and hefty hose clips.

The question then became one of fitting the above new 51mm exhaust hose to the existing LP40 Waterlock, and for this I was sold a Vetus HA3060 Hose Adapter. I have now been assured twice ( by the vendors-specialist, his manager and in the posts above ) that this will physically do the job and will not melt, provided the run of 51mm hose is more than a metre , that this unit is cut down to relevant size and is fitted close to the Waterlock, and that any back-pressure will prove to be negligible and inconsequential. I'm chasing Beta Marine on this.

I can't see a modest back-pressure causing any damage, but if it emerges as a constraint, then I'll need to think again. With the inputs from everyone, including here, I'm sufficiently reassured to give it a try.

Many thanks to all.
 
macd said:
This was all debated at some length in another recent thread also started, if memory serves, by zoidberg. The consensus of well-informed participants was that it's OK (within limits, obviously), also suggesting a more elegant way of achieving it. Beta, who I think provided the engine in question, are quite relaxed about such measures, only stating that exhaust back-pressure should not exceed a prescribed value.
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OK so you install the undersized muffler and reducer, measure the back pressure and it’s to high.
Then what?”
 
zoidberg said:
and that any back-pressure will prove to be negligible and inconsequential. I'm chasing Beta Marine on this.
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Just to put this into perspective: I have the larger Beta 20 hp with a high rise exhaust bend, provided by Beta. The ID of this bend is circa 35mm. Reason is that the 51mm ID hose has to swallow not only the exhaust channel but also the water jacket.
As already said, the reduction to 40mm hose is unlikely to be a problem.
 
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