Spitfire 1500 Fuel Line help?

[Harveyzone]

Hi all,

Can anyone advise on where to start?...

I have jjust started up my Spitfire 1500 for the first time this year, and, after the usual 'laid up' issues - low battery, fuel taking ages to pump through etc - it started with no real drama.

I came back to the car, half hour later to find a large pool of petrol under the car, and a drip from the fuel line somewhere near the back.

Any way, fuel line is all new at the engine end, so figure that I should just replace it from there back (if nothing else, I have no idea how old it is, and whatever I replace it with should be E10 safe), but there is remarkably little about this in Haynes, Autobooks, or any other manuals that I have. I have no idea if it is a single hose, how long it is, what gauge it is, if there are joins or connectors etc, so I cannot ensure I have everything that I need before I start the job.

Does anyone have any advice, guides, photos etc as to what I need, how easy(/hard) it is to do, how long it will takes, or any hints/tops to help me on the way?

Cheers,

Tom.

Edited June 4, 2022 by harveyzone
Gramma!

[RobPearce]

There should be a single run of solid pipe - use cunifer or copper - from the engine bay to the boot floor. It runs along the chassis main rail (through holes in the outriggers) and is held by clips. On early cars it's the same clips that hold the brake pipe it runs next to.

There's a rubber hose connecting the front of that pipe to the fuel pump, and probably a short one at the back to connect it to the pipe that runs up through the boot floor, up the side of the tank, across, and through an olive fitting in the top of the tank down inside near the bottom. Replacing that piece of pipe is a tank out job.

You should really try to keep it to only those two rubber bits.

On a 1500, I think the pipe is 5/16" OD (which is pretty close to 8mm) - it was 1/4" on the roundtails.

If you can get the car over a pit or on a four-post lift, it makes the job MUCH easier. I found it easiest to feed the pipe forward from the back, since the front bit is simple and the back is where the complex bends are.

[Harveyzone]

Thanks Rob - I didn't realise that the centre section was solid. 

I don't have access to a lift or pit, but have now got it up on axle stands so I can have a better look. It appears to be leaking from the join between solid and rubber pipe. I will have a better look tomorrow and try and get it apart to have a look.

The solid pipe - does it often fail, or are they generally reliable. Wondering if I should replace it or just the rubber hoses.

[RobPearce]

The original solid pipe was made of steel. They rust - not especially fast but if yours is the original one then I'd be a bit surprised if it hasn't rusted almost through. If it's already been replaced with copper or cunifer then they're generally pretty long life, unless they get impacted or crushed. The copper ones can, theoretically, work harden from vibration if not properly supported, and that can make them fracture, but it's rare. So on that basis, if it were my car, I'd give it a good inspection. If it's steel, replace. Otherwise if it looks undamaged and properly clipped in place, probably leave it. (Well, if it were actually mine, I'd be tempted to replace as I have a big reel of pipe in a drawer, but....)

[Harveyzone]

I've just been out and had a quick look (in the dark), and, although I cannot be sure, it looks like there is a single run of what seems to be a hard plastic pipe from the top of the fuel tank, down through the boot floor, along the chassis next to a brake pipe, through to the front of the car, where it connects to a rubber R6 hose into fuel filter/pump/carbs as it comes out under the bulkhead. I cannot tell if there are any joins in it. The point that I thought was leaking may not be a connector, but a clip. Possibly a split in the plastic, or it is running down from somewhere else.

The schematic below (from Canley's) suggests that there are a couple of joins in the line, but I cannot see any in mine...

It would be useful if I could see a schematic of the fuel line in relation to the whole car so I could see where the joins are supposed to be, e.g. the transitions from steel to rubber etc, but I cannot find one.

I think I might have to disconnect the line at the fuel filter, and take it out all the way back to the tank to see what I have got from changes by a previous owners, and possibly replace the lot.

[Harveyzone]

Another question (sorry)... Is copper fuel line ok with E10 fuel?

[RobPearce]

10 hours ago, harveyzone said:

it looks like there is a single run of what seems to be a hard plastic pipe

Interesting. I know the factory used hard plastic pipe on the later saloons, so maybe that's original if yours is a late one.

10 hours ago, harveyzone said:

The point that I thought was leaking may not be a connector, but a clip. Possibly a split in the plastic

If the clip is not well fitted it's possible it's rubbed through. That's much more likely with plastic pipe than steel or copper, although it can happen on any.

9 hours ago, harveyzone said:

Another question (sorry)... Is copper fuel line ok with E10 fuel?

Yes, no problem with ethanol and copper. At one time, copper was used in distillery plumbing.

[Harveyzone]

Thanks Rob, your input is invaluable to an inexperienced hobbiest like me 🙂.

Ok, so got underneath today with some proper light and had a proper look. And I was wrong.

It is metal pipe from bulkhead to the end of the floor pans, then a small length of rubber joins it to hard plastic pipe that goes all the way up to the tank, where it connects to the tank with another short length of rubber. I think it was leaking from the one of the connectors on the rubber line between metal and plastic. The metal hose looks good, so I might just leave it.

If I replace the hard plastic with 8mm rubber fuelhose, all the way back to the tank (might put another filter in between at the side of the fuel tank), will the rubber hose be ok under the car? I assume that there is a reason why they used metal underneath, and rubber/plastic in the boot and engine bay sections.

As an aside, and while I am messing with fuel lines, what is supposed to happen to the breather on the fuel tank? On mine there was a hose clip, and a tiny length of rubber hose that has largely deteriorated. I have taken it of, to make sure that the deterioration was the rubber and not the tank(!). The parts catalog shows a short length of pipe that goes nowhere, but is the pipe necessary (looks pretty pointless to me), or should there be a filter or something on it, or it route somewhere else?

Cheers,

Tom.

[Harveyzone]

Interestingly it seems to also have part number 153960 on the plastic line, which is a spring like "sleeve protection", and the parts catalogue only shows it on USA spec cars. It does suggest that the plastic line is original though.

I do not know the year of my car - a previous owner did their best to loose it, I suspect for tax reasons - but from detective work I believe it to be an early 1978 from the spec of various parts (any of which could unfortunately have been changed over the years).

[RobPearce]

You should not use rubber hose under the car except for short (2 inch) joints. Rubber is flexible and will dangle, leaving it vulnerable to speed humps or bits of road debris. The plastic pipe is semi-rigid and only needs supporting every foot or so but rubber would need a lot more, so stick with rigid plastic or copper.

The breather pipe on the tank is primarily there for US spec cars. Because of evaporative loss emission rules, US cars (and especially California ones) needed a vapour recovery system consisting of a charcoal canister and a valve. The tank breather passed through the canister to catch all the hydrocarbon vapour, and the valve opened to the inlet manifold when running at light load to suck those trapped hydrocarbons into the engine to burn. UK market cars didn't need that, so they had a vented fuel cap, and the tank breather was capped off with a stub of hose and a plug. The alternative would be to run a long length of hose (or pipe) from that breather across and down to exit through the boot floor. GT6 tanks breathe that way. But you want that breather pipe to run up as high as possible first, then down and out as low as possible, so that you don't lose fuel through slosh.

[Harveyzone]

Cheers. I will get a length of 8mm copper pipe and continue the run. I will use rubber to go from top of tank through the boot floor to join to the copper at the chassis with a fuel filter in the middle at the side of the tank. I will then be E10 proof from top of tank to carbs. I will also put a little length on top of the breather to reduce spillage/splashing.

If I feel brave I might do a single run of copper from front to back and take out the old piece. Any ideas why there is a join in the middle? It appears to be a standard practice. It feels like it's inviting leaks at the joints where it is hard to access.