Correct internal diameter for 8mm diesel fuel line?

[Captain Crisp]

I need to re-route my 8mm fuel line upstream of the primary filter - I see I can buy this with various internal diameters... is there a right one?
Many thanks,
Crisp

 

[coopec]

I give up!

Can you give us another clue?

What size fuel line do I need?

 

[VicS]

I need to re-route my 8mm fuel line upstream of the primary filter - I see I can buy this with various internal diameters... is there a right one?
Many thanks,
Crisp

Isn't 8mm 8mm ID ?
?

 

[coopec]

I need to re-route my 8mm fuel line upstream of the primary filter - I see I can buy this with various internal diameters... is there a right one?
Many thanks,
Crisp

Have you checked the diameter of the spigot?

 

[andsarkit]

Use ISO 7840 hose with whatever ID fits the existing spigots. ASAP Supplies can supply suitable fuel hose.
You are unlikely to need more than 6mm ID so use whatever fits best.

 

[Avocet]

Not quite sure I understand the question. Are we talking about "rubber" fuel hose that pushes on to a spout? If so, is the outside diameter of the spout (disregarding any bulge at the end to help stop it pushing off) 8mm? If so, just buy hose listed as "8mm". From memory, the inside diameter will be a bit smaller (7.6 rings a bell), but it will stretch easily. Is it for petrol or diesel?

 

[Poey50]

Your question only makes sense by assuming that you think "8mm fuel line," refers to the outer diameter. As VicS indicates, it refers to the internal diameter (ID) so you already have the answer. You only need to ensure that the hose is suitable. ASAP sell it.

 

[coopec]

Be very careful that the fuel hose meets the required standards.

SAE J30R14T1 is the standard for ultra-low permeation properties. This type of hose is typically approved for use with leaded and unleaded gasoline, diesel, biodiesel, E85, methanol, ethanol and gasohol fuels.

https://www.gatesaustralia.com.au/~/media/files/gates-au/automotive/brochures/cooling-system-and-hose-products/gates-fuel-hose-flyer--june-2018.pdf

 

[Captain Crisp]

Thanks for the advice - it's 8mm outside diameter...
Crisp

 

[Captain Crisp]

I'm a bit concerned now that the current line is the wrong material... as in, it looks like clear pvc to me? Is that a problem? You can see it here going into the primary filter:

 

[andsarkit]

In the past I have had reinforced PVC fuel pipes and it worked fine but went stiff after a while.
Nowdays a surveyor would fail these on safety grounds as they have no fire resistance..
As said above, use proper hose rated to ISO 7840 and probably also marked LLoyds approved or similar. The cost of a few metres of hose is nothing in the cost of maintaining a boat and you know you will have done it properly.
ASAP

 

[Poey50]

Thanks for the advice - it's 8mm outside diameter...
Crisp

In that case the 8mm dimension is irrelevant. As said above you need to measure the diameter of the hosetail /spigot and buy the correct hose material based on that dimension alone.

 

[Captain Crisp]

I don't think there's a spigot where the existing line joins the primary filter... it's just a copper olive compression join... or am I missing something?

 

[VicS]

I don't think there's a spigot where the existing line joins the primary filter... it's just a copper olive compression join... or am I missing something?

I hope you are missing something or I have misunderstood.

Surely not a soft plastic hose fitted directly into a compression fitting ??

Go to the section of ASAP's website covering fuel hoses of all types and sizes rather than the link in #11 and scroll through to the ISO hose and the ready made hoses

Boat ISO7840 Approved Fuel Hose

Maybe you need to add hose tails for plain ISO 7840 fuel hose or may be you need a ready made hose with spigots to fit into compression fittings.

.

 

[Poey50]

Judging by your photo and following up on VicS's comment you might consider replacing your primary filter with something like this Racor 120 clone. They are well made and ludicrously cheap. I have an original Racor and the copy and I can't see the difference.

Oil Fuel Filter Water Separator Diesels Engine R12T For Racor 140R 120AT S3240 | eBay

 

[andsarkit]

That looks like a CAV/Delphi filter. They are usually 1/2" UNF threads but may be M14 x 1.5. If you need to get hose tails, check the size first.

 

[penberth3]

I don't think there's a spigot where the existing line joins the primary filter... it's just a copper olive compression join... or am I missing something?

No, you're not missing anything. A spigot goes up the inside of the hose, your compression fitting works on the outside of the hose/tube.

 

[penberth3]

I hope you are missing something or I have misunderstood.

Surely not a soft plastic hose fitted directly into a compression fitting ??.....

Standard method for nylon tube, which this might be, rather than PVC.

 

[Captain Crisp]

I'm afraid it is a soft plastic hose fitted with a compression fitting... not my work, guv...
Seems to have held together for the 3 years I've had her, but I'll get to work and sort this out as you advise...
While I'm in confessional mode, I also noticed that the fuel shut off valve under the diesel tank doesn't actually shut the fuel off... that doesn't sound too good either...
Thanks all!

 

[Captain Crisp]

Standard method for nylon tube, which this might be, rather than PVC.

Ah... that makes me feel better!