E10 Petrol and Fuel Lines

[ThreePointFive]

This goes far beyond just my car, Defenders or even Land Rovers so thought the Int. section would be the best place.

After a saga I won't go into here, I need to replace every rubber fuel line in the car (petrol V8). Rightly or wrongly, I took out the metal pipe from the tank to the filter and replaced everything with a name brand fuel hose meeting DIN 73379 (which is meant to be safe for E10). In the 2 years since I did this, most of which it lived in my garage, it has perished to the point of spraying high pressure fuel everywhere. At the MOT test station.

I originally thought the pipe had perished from the outside-in as the crazing is all along the pipe but only one part has so far leaked. A bit of reading suggests that this is how E10 rots out fuel lines - the vapour seeps out and dries out the pipe, which cracks and then splits when it can no longer flex. Either way, the pipe I bought specifically to handle E10 is now perished and unable to do its job. According to the internet, SAE J30R9 is required for E10 but it seems like DIN 73379 includes that standard. No one I've spoken to in the trade is willing to recommend a rubber hose and I'm told this is becomming more common as an issue.

So the point of this post. I'd like:

1. Views on the use of (correctly rated) rubber fuel hose for the entirety of the system

     a. Recommendations for high quality, E10-appropriate fuel hose

2. Views on having the original metal pipes re-made (they are kinked, unfortunately) and then having only the joints between the pump, filter and fuel rail as rubber.

     a. Recommendations for where to get metal fuel pipes made up using the original as a rough template.

Here is a rough diagram of my system as I always find it easier to explain in crayon.

Option A has 10 joins, B has 6. I prefer the idea of fewer joins but in this case, it's not a join that leaked...

Also, even on the metal pipes I will have to use rubber as unions between pumps, filters etc., so does that really give any benefit?

Any thoughts/comments appreciated as I have an undrivable car.

[Gazzar]

Is hard nylon pipe suitable? Old school series style.

[smallfry]

I would not use rubber hose for any complete run. I would stick to Gates hose, and make sure it has J30R9 printed on it. I notice a lot of cheaper stuff has the spec on the packet, but not on the hose itself, just stating something like "fuel hose" and possibly the size.

E10 apparently leeches out any zinc. This will mean any plating on the inside of a metal fuel tank, and steel pipework. This is not in itself a problem, other than E10 also allegedly absorbs water, which can lead to rust problems in the tank, lines, and system components. The displaced zinc could also cause blockages in injectors.

E10 also, apparently attacks certain aluminium alloys, which again is a major concern for the fuel system components of older engines. In practise of course, only time will tell.

As Kunifer tubing is a copper/zinc alloy, I think this rules it out, sadly, and IMO, repeat IMO, copper tubing has no place on a motor vehicle, and yes I am aware that many people have copper brake pipes etc, but its your funeral, as they say.

If you look at any modern vehicle (all the ones I have seen in any case) use nylon or polyethylene pipes with either quick fit couplings, or short lengths of appropriate (hopefully) hose, with either spring or crimped clips. NOT "jubilee" type. They also have HDPE fuel tanks.

I would be looking at nylon pipes myself, with short joining lengths of rubber. 

TBH this is another reason why I think I will stick to diesel.

[Bowie69]

I've nylon pipe in LGT, though I didn't fit it, and handles low pressure at the moment only, assuming rated to 100 PSI it should be fine, but then you have to get unions and stuff to work with it.

If it were my truck, and unless you set fire to it, you intend to keep it, I'd see how much I can get done in teflon lined stainless (black obvs) braided line, with AN fittings where appropriate. No leaks, teflon doesn't get affected by ethanol, and very, very robust.

One of the NHRA rules for certain classes is no more than 12" of rubber line anywhere on the vehicle, whilst I've not actually kept to that (I have about 4ft running across the bulkhead behind the engine), I understand their reasoning entirely, and would be something to aspire too, without hamstringing yourself.

I suppose one of the most important bits is to make sure any rubber is easily serviceable, and very visible -this is where the 4ft of line on mine if OK IMHO, you can see the whole length of it, and inspect it easily. I would love to get a fitting on the V8 fuel rail and I would replace it with AN line as the other end is the mini fuel cell under the bonnet.

[dave88sw]

I ordered some e10 compatible stuff from merlin motorsport, i believe it was cohline or something similar.  Its been on 2 years and still looks like new and is just as supple as the day i fitted it.  It was really quite expensive compared to the long rolls of cheap stuff you can get on ebay but i didnt want to be replacing it after a relatively short period.

[ThreePointFive]

Thanks All, very helpful suggestions as always.

An option that phone calls to different places has suggested is cutting my existing pipe and putting a flare on the end to connect a flexi hose. That would eliminate a lot of the run along the chassis rail which I can't see/check if it was flexi.

PTFE seems to be the gold standard, so that's a decision made. I only need short joints of it to connect the hard lines.

14 hours ago, dave88sw said:

I ordered some e10 compatible stuff from merlin motorsport, i believe it was cohline or something similar.  Its been on 2 years and still looks like new and is just as supple as the day i fitted it.  It was really quite expensive compared to the long rolls of cheap stuff you can get on ebay but i didnt want to be replacing it after a relatively short period.

I thought I had fitted their expensive Cohline stuff throughout, but on closer inspection it's only from the filter to the fuel rail and the return to the metal pipe just under the bulkhead (because it was meant to be better with heat and passes over the exhaust). That stuff does not seem to have been effected. I'll replace it anyway because I want to eliminate the join for the small filter on the return line.

 

19 hours ago, Bowie69 said:

I suppose one of the most important bits is to make sure any rubber is easily serviceable, and very visible -this is where the 4ft of line on mine if OK IMHO, you can see the whole length of it, and inspect it easily. I would love to get a fitting on the V8 fuel rail and I would replace it with AN line as the other end is the mini fuel cell under the bonnet.

I looked at going to AN lines but I can't work out from my short experience with it, how to connect it to the pump and fuel rail ends. It would make the filter fitting beautifully easy though.

[ThreePointFive]

21 hours ago, Gazzar said:

Is hard nylon pipe suitable? Old school series style.

I had that when I was running it as a 3.5 but I'm even more nervous that will melt than I am with the other options. The nylon can just get old and snap even without the E10 influence from what I've read.

[Bowie69]

7 minutes ago, ThreePointFive said:

I looked at going to AN lines but I can't work out from my short experience with it, how to connect it to the pump and fuel rail ends. It would make the filter fitting beautifully easy though.

This sort of thing : AN-6 BLACK Straight FEMALE SWIVEL to 5/16 8mm HARDLINE TUBE Compression Fitting | eBay

In fact this may work on the fuel rail as well, which means I may be putting an order in for similar very soon. For teflon lines, you need to make sure the fittings are the correct sort.... a google or asking a question of two of a supplier should get you there.

[Bowie69]

I used this supplier for all the PAS hose setup on LGT:

 

Torques_U.K | eBay Stores

[Nonimouse]

Maybe stainless pipe?

I've had to replace the one and only rubber pipe on my Vitara - solely down to E10 - and she's 15 plate

[Bowie69]

If I were going hardline, then it would be cupro-nickel, e.g. Clarik 8Mm X 7.5Mtr Cupro Nickel (Kunifer) Fuel Pipe : Amazon.co.uk: Automotive

I'd say stainless is probably a bit hard for use on a vehicle, tricky to put a flare on without splitting .

[Nonimouse]

11 minutes ago, Bowie69 said:

If I were going hardline, then it would be cupro-nickel, e.g. Clarik 8Mm X 7.5Mtr Cupro Nickel (Kunifer) Fuel Pipe : Amazon.co.uk: Automotive

I'd say stainless is probably a bit hard for use on a vehicle, tricky to put a flare on without splitting .

The food grade tube is 'more malleable' and better quality

[Simon Smith]

In the garden machinery service industry we find genuine Briggs and Stratton fuel hose lasts many years with E5 fuel and they claim the same for E10.

It's 1/4" bore and can be ordered from any garden machinery shop. Part number 395051R for 25ft.

[Gazzar]

That's very useful. Makes sense as the sugar lobby were successful in pushing ethanol into the US a long time ago.

[Bowie69]

1/4 is too small for V8s unfortunately. 

[FridgeFreezer]

On 3/27/2023 at 12:59 PM, ThreePointFive said:

The nylon can just get old and snap even without the E10 influence from what I've read.

Ask any D2 owner who's snapped the radiator bleed pipe saw two do it in the same car park, the pipe just crumbles to shards... 2nd one also managed to snap the nipple of the plastic-tanked radiator for good measure!

[Happyoldgit]

I won't put E10 in my '43 Jeep.

[ped]

i've not put e10 in my v8 so far but i do use it in my chainsaws and stump grinders , i try to drain fuel out when i don't use them regularly though
my v8 fuel lines are getting on for 12yrs old and i'm thinking of putting stainless braided on when i do the fuel lines for my work truck as it makes sense to buy enough to do them at the same time