Poking around the ol' V12, I noticed that when the hoses connecting the two fuel rails were replaced, the mechanic put clamps around them. And I have remembered reading that clamps on barbed fuel rails are not good, as they can cause leaks, and fuel leaking onto a hot engine isn't really ideal. The original certainly didn't have them, just pushed on with end caps.

Is this a problem? And if so, how serious? If this is an example of sloppy work from what is supposedly one of the top experts in the country, I will not be impressed.


This is the AFTER shot, with the worm drive (?) clamps on the new fuel hoses.



This is the before shot, with no clamps on the fuel hoses. At least the spark plug leads have been made neater since this....

 

Clamps on barbed nipples?

Not needed and not good practice. The barbs are rather sharp; pressure from the clamps might result in damaged fuel hoses....especially if the clamps are very tight

But....I wouldn't be alarmed. Not an emergency. Just replace the hoses without using clamps, more sooner than later. IMO.

Cheers
DD

 

Thanks, Doug. So within a couple of years at most rather than some time next century should be fine? I wonder why there are even hoses there in the first place, rather than metal pipes.
As an aside, "barbed nipples" sounds very kinky....

 

SD
These are very simple to change yourself. Buy a length of top quality high pressure fuel hose, then depressurise the system with a rag round a slightly opened joint, engine cold. Then cut the hoses and wiggle them off and push on the new ones.

 

Huh. Something even a rank incompetent like me can handle? I've always been very leery about fiddling with the fuel system, due to an aversion to setting my car on fire.

I read to depressurize the system you pull the fuel pump fuse and turn the engine on and let it die. Your way seems different, or does it assume that to begin with? The rag's to soak up the petrol I assume. Do you mean to ease one end off while the engine's cold with a rag to soak up the petrol spill (I'm not sure about the risk of any petrol spilling onto the engine, even cold--if it's not all perfectly mopped up, it might not be fun), then you can remove the other three safely? So once the system's depressurized, there's not actually any petrol in those hoses I assume. Or shouldn't be.

Are the metal caps that go at the ends easily available? As in, not some fancy Jaguar thing.

 

This looks like a helpful thread as well:
injector hose replacement - how to depressurize fuel

 

SD
You re-use the metal end pieces. Once the system is depressurised, there will be a bit of fuel in the pipe, but a rag will soak it up and all will be well.

 

They're not there any more. The bloody JEF garage seems to have made off with them. I'll check again in case they're hidden, but I'm not impressed.

 

Another reason to do your own repairs and come here to ask, how do I ******

 

Indeed. And if I had a garage I'd be doing a lot more, believe me.

 

You can buy them easily enough, SD. Talk to this guy and tell him what you need, for example. His stuff is top notch.
https://mrinjectoruk.co.uk/

 

When Jaguar fitted the hoses at the factory, they used a heavily reinforced hose which will stay on fine without clamps.

I tried two different brands of replacement hose, Goodyear and Gates, and neither gripped the barb as tightly as the original. The Goodyear soon began to leak.

So I ended up putting clamps on, just to hold the hose on the barb. No need to tighten them up too much, just lightly. Obviously they would damage the hose if too tight.

 

I don't know if they make it in the correct size, but in these types of hose there are generally 2 kinds: regular and push on. The push on is designed to be leak free without clamps. From memory, you need an ID of 7.9mm, and of course I couldn't find any with a quick search.

 

Everyone says its bad, but the XJ6 uses clamps, so I'm not sure what the big deal is. You do want to use good fuel hose clamps though, they clamp more evenly, where generic hose clamps form a less perfect circle.

 

The XJ6 used a joint designed for a clamp, the XJS uses a different type of joint.

 

The rail has only one barb, the injectors are still multiple barbs, just like the V12.

So the argument is that clamps were not needed originally and that factory hoses were more reinforced and tighter fitting, right?

Well, isn't that exactly what the clamp is for? Its reinforcing the area and tightening the grip on the barb, as a smaller hose would.

 

Hi Someday

None of my 1989/1990 XJS's have those Rubber Hoses as shown in your photo
which seems to be the worst possible place to have a Petrol leak



No Rubber Hoses as in your Photo with or without Clamps

(except for the two curved ones at the front)

 

The design changed with the move to O ring injector hook up.

 

Thanks for your input, everybody. Very helpful. I've been doing a lot of research and reading myself, to the extent I can (most people talking about clamping fuel hoses seem to be talking about marine engines for some reason).

If the nipples for the cross-rail hoses do indeed only have one barb (I've tried to find photos, but with no luck), then the clamps probably aren't doing any harm. Another site says that fuel hose is durable enough to be clamped without damage. Jag Lovers talks a lot about barbs and clamps, but focuses on the short hoses that lead to the individual injectors, the ones you can clearly see in OB's photo. Those are notorious weak spots, so why Jaguar decided to remove that rubber but add more elsewhere I do not know--though presumably it's slightly cooler on top of the vee than in its bowels.

At any rate, as most discussions on fuel hoses seem to focus on the pre-facelift injector connector nipples, I haven't been able to determine what the post-facelift nipples look like (and Google Image searches for "post-facelift nipples" aren't likely to help much... ).

The issue, I suppose, is not whether factory hoses needed clamps, but whether aftermarket ones do. As JagBoi notes, it's not an easy to find hose size apparently, though having said that, I've just done a search for it in Japan and found a couple of places that have it. This place has Parker 7.9 mm for about US$20 a metre.

At any rate, I'm going to keep a close eye on them, that's for sure. I keep trying to tell myself that Jaguar Engineer Factory are specialists, experts, and know what they're doing, but sometimes (increasingly) I wonder if I'm not just trying to reassure myself that spending all that money was worth it (though for most things, it probably was--no more rain leaks, for one thing).

I also have some more urgent areas to tackle. I suspect my aircon heater core is leaking just a bit, as the fogging on the inside of the window is getting worse, and I've been able to smell a sort of sickly sweet smell (my wife called it "maple syrup") that is apparently a symptom of leaking; plus there's no air from the passenger window-side vent; and in addition to that the car clunks/rattles in low speed turns or bumps, so I suspect there might be something loose around the diff. Once XKs Unlimited bothers to get back to me regarding the warranty for their remanufactured harmonic damper, I'll get those symptoms checked out.

You're never bored with an XJS. Frustrated, disappointed, angry, yes. But never bored....

 

Hi Someday

Would JEF be ok about fitting your Harmonic Damper, or do you think they would want to supply and fit their own?