Fuel pipe material

[Bodach na mara]

Following on from the fuel filter thread, I wonder what people use for fuel pipes. The system on Wight Dawn uses copper tube (1/4 inch or 6 mm, not sure which) up to the lift pump then some sort of flexible armoured stuff to the main filter then steel tube to the high pressure pump. To complete the mixture, the leak-off return is in clear plastic. Over the years I have had the odd leak from the steel stuff due to failure of brazed joints at banjo fittings but most of my problems have been with the copper. The fuel seems to be as searching as antifreeze and weeps from fittings frequently.

At one time I installed a second filter and change-over valves. That was a disaster. Not only did this introduce an extra set of compression joints to leak but the fuel cocks that I used (brass 1/4 turn with lever, as sold in chandlers as suitable for gas or fuel) leaked as well. That has now been removed.

I looked at some fuel hose in ASAP web site. What put me off a bit was the "guaranteed for 5 years" bit. I expect a lot longer from such an installation. How do you join it? Hose clamps and stubs of copper tube seem to be implied, but that takes me back to compression joints to link into the filters and pumps, and I read that such joints are prone to leakage in diesel systems. Then there is the leak-off return. I rather like the clear pipe and it has given no trouble at all. But I understand that the BSS suggests that plastic pipes are not acceptable.

All suggestions welcome. I am a bit fed up with the slight smell of diesel and the need for regular cleaning of the bilge to keep it slight. I suspect however that here is one leak (fom an inaccessible bolt on the HP fuel pump) that will remain after I have renewed the rest of the system.

 

[NormanS]

Compression joints on copper should be OK, and shouldn't leak, and don't with me. You need to be sure that the olives and fittings are the same size as the tube, and not a mixture of Imperial and metric. At some point, if your engine is flexibly mounted, you do need at least a short section of something flexible.

 

[Momac]

There is some reading and advice on the following including suitable materials and British Standard reference for flexible fuel lines. The number of joints in fuel pipes should be minimised.

Download chapter 2

http://www.boatsafetyscheme.com/site/2ndedBSSEssentialGuide_212.asp

 

[rob2]

Surveyors tend to favour copper pipes as they are not flammable, although many on the forum say they give the most trouble. For what its worth (not much) my experience is that so long as the softer copper olives not brass are used, they seal well and its the limited lifespan of the rubber hoses that makes fuel pipes a maintenance issue. Copper pipes do need to have some excess length and preferrably some curvature in them to accomodate movement and vibration. On the whole, with rubber hoses I use Jubillee clips as a temporary fixing, preferring C clips (is that the right terminology?) to make up permanent hose ends. They are very easy to nip up with a pair of pincers and can still be pried open if neccessary.

Rob.

 

[VicS]

preferring C clips (is that the right terminology?) to make up permanent hose ends. They are very easy to nip up with a pair of pincers and can still be pried open if neccessary.

O clips ! The things with either 1 or 2 ears

 

[PuffTheMagicDragon]

I have not had any problems with brass olives when fitted in the correct size that matches the pipe and the fitting for which they are meant. Nine times out of ten any leakage is caused by over-enthusiastic tightening and / or poor alignment.

 

[Bodach na mara]

Thanks for all the advice. I think that I have been over-enthusiastic in tightening at some point and that may be what is causing he seepage. I did wonder about the rubber pipe but think that I will leave alone the bits that are not leaking.

I did find a pinhole in an injector pipe just before I laid up but that is now sorted. Possibly some of the other apparent seepage was from the spray!

 

[PuffTheMagicDragon]

Best thing for locating a leak is a blue paper napkin: it goes very dark upon contact with diesel.

 

[rosssavage]

Replaced my lovely 3000psi rated, fire impervious, impact / penetration / abrasion resistant stainless braided hoses for yucky, perishable, flammable BSS A1 approved rubber hoses.

To make my boat 'safer' apparently.

All fittings swaged on. No leaks. (Yet... )

 

[fisherman]

Hydraulic hose. No problem over 13 years/9000 hours. As far as fire is concerned, not tested but an engineer said he could burn through copper quicker than hydraulic.

 

[Evadne]

Copper pipe. I got leaks where it runs through the cockpit locker due to wet ropes lying on it, but when I replaced it I painted the pipes with Smoothrite and ran them in mini trunking, and so far they're fine. I now carry a long length of flexible pipe and jubilee clips, it got me out of trouble last time and I wouldn't be without it now!

 

[PetiteFleur]

I used copper pip from the tank to the primary CAV filter then approved flexible rubber pipe to the engine with swaged plain ends. All compression fittings and no problems untila about 50 hours when I had an air leak somewhere - nipped up all the compression fittings and not had any problems since - now 5 years on.

 

[Bodach na mara]

Thanks All. So I will renew the olives at the compression joints that weep, using copper olives. I may need to renew a short bit of copper tube where I need to renew the olives as when I cut the old ones off the tube remaining may not reach the connection point. The rest will be left well alone.