BMC 1.8 Fuel Leak

[NewCanalBoy]

I have a fuel leak, sprays out when I start the engine.

It's coming out of the join you see in the photo. I've tightened it up but made it worse. Does this have to be a solid line ? Seems odd that it is in mid air and not supported ?

I've had issues with my engine mounts so it's vibrated bits and pieces.

What happens if I loosen these pipes - are there olives in there that are damaged ? 

Do I just have to get new pipes ? Can I get these new pipes ?

[Tony Brooks]

1. Yes, it is ordinary copper pipe and probably imperial, so measure it for the correct diameter. Most decent chandlers will sell it.

 

The extra non-standard bracketing for the fuel filter suggests the filter has been suffering excess vibration. That would tend to loosen the olives in that joint.  If it is metric pipe I fear it has a thinner wall so would crush more easily.

 

That "filter" would seem to be an agglomerator water trap, rather than the typical engine fuel filter. Those are normally fitted somewhere between the tank and lift pump. The extra length and weight would tend to make it vibrate in its bracket a bit more than the standard filter.

 

PS, I think that I would try to put a coil in the pipes either side of that joint or a single one if you fit a complete new pipe with no centre joint.

Edited March 16, 2023 by Tony Brooks

[Tracy D'arth]

Replace the pipe with a fuel hose.

[NewCanalBoy]

I was wondering whether it could be a fuel hose rather than solid. Didn't know if there was anything in the BSS about it ?

Edited March 16, 2023 by NewCanalBoy

[Tony Brooks]

18 minutes ago, NewCanalBoy said:

I was wondering whether it could be a fuel hose rather than solid. Didn't know if there was anything in the BSS about it ?

 

At one time, the BSS said something along the lines of "minimal practical length" for approved fuel hoses, but am not sure now. With the great variation in inspection standards, I would not risk it. Especially as the pipe on the original engines was solid steel.

 

Although more work, it would probably be more satisfactory to get the thing back to the standard 1.8 configuration, so the filter is much lower and closer to the head, that better resists it waving about by vibration.

[David Mack]

21 minutes ago, NewCanalBoy said:

I was wondering whether it could be a fuel hose rather than solid. Didn't know if there was anything in the BSS about it ?

The BSS has rules for fuel pipes and hoses (which must have the correct markings). But you should read the BSS for yourself, rather than relying on what some bloke on the internet says.

[adrianh]

If you are replacing the copper pipe then try and use a new length of tube end to end.

The added weight of the unsupported pipe coupler is adding to your problem and increasing the likely hood of a pipe fracture.

If this is a 1/4 inch od copper pipe then you can purchase the thick wall ( sorry can't remember the spec) and barrel olives from chandlers. The Boatyard at Staverton on the K and A have this and sell on line.

Take care not to overtighten olives on reassembly

[Tony Brooks]

FWIW, on the 1.5 upon which the 1.8 was based the SINGLE section pipe between lift pump and filter was secured in a rubber bush in a bracket secured by the centre bolt on the rear tappet/pushrod cover. That helped damp pipe vibrations.

[john.k]

Looks like it may be crossthreaded or stripped in the pot metal CAV top.

[NewCanalBoy]

6 hours ago, john.k said:

Looks like it may be crossthreaded or stripped in the pot metal CAV top.

It's not leaking from there, it's coming out of the bottom of the joint lower down.

11 hours ago, adrianh said:

If you are replacing the copper pipe then try and use a new length of tube end to end.

The added weight of the unsupported pipe coupler is adding to your problem and increasing the likely hood of a pipe fracture.

If this is a 1/4 inch od copper pipe then you can purchase the thick wall ( sorry can't remember the spec) and barrel olives from chandlers. The Boatyard at Staverton on the K and A have this and sell on line.

Take care not to overtighten olives on reassembly

If you buy the pipe I assume you have to have a pipe bender too - or you're going to crease the pipe when bending ?

[Tracy D'arth]

With soft copper pipe and care it can be nursed to shape by hand. If its a bit stiff, anneal it first by heating to red heat and cooling it either in air or water. (quenching)

[NewCanalBoy]

Well I've just attempted a fix - and it's worked 😇 

 

Taken out that connector, cut off the ends to get rid of the olives, went and bought some very tight fitting fuel line, pushed over the pipe as far as I could physically get it and clamped everything up.

Pumped the primer and we were away - no leaks.

 

So I know this is not long term and have to get a proper pipe made asap - but at least I can charge my batteries occasionally.

 

Very, very difficult to get hold of anybody right now - spring is on its way !!

Edited March 17, 2023 by NewCanalBoy

[David Mack]

A BSS inspector will take a dim view of a hose pushed onto a piece of plain pipe and held on by a jubilee clip or two. But if you crimp an olive around the pipe first and push the hose over that then fit hoe clips it is usually acceptable.