So............
Having a lot of fun working on the engine (replacing fuel hoses, new injectors, new ignition harness, clean the Vee etc.).

When I removed the fuel lines with metal pipes connecting to the fuel rail I observed that the rubber hose sections were adjoined using single ear stepless hose clamps:



I therefore cut the rubber hoses with the intention of refitting using the same type of clamp after I added new rubber. I used a soldering iron to remove the existing rubber hoses. Barbs seem in good condition.



I now gather that originally the OEM arrangement would have included collars covering the connection between rubber hose and metal pipe i.e. the rubber hoses have been changed before!!

Now with this setup there have been no fuel leeks over last 5yrs of driving, so seems okay. My question though is would the rubber hose part originally been seated using ferrules


I.e. No clamp (as originally used on the fuel rail hoses); If so pondering whether to revert to this setup or use clamps as before?

Thoughts appreciated!

Quentin

 

I'm in the "no clamp" camp and have never had any problems.

The eared clamps you mentioned are "Oetiker" clamps



Cheers
DD

 

Thanks Doug,
So just a ferrule at either end of the hose, assuming barbs are in good condition?

 

Right !

Cheers
DD

 

I've seen (and been told) various figures for the pressure rating of barbed fittings but it seems that a barbed fitting is good for 100 PSI (and maybe more) even without a clamp or ferrel. so the stock fuel system wouldn't even be close to that.

 

The original fittings had a collar on them.
OEM pipe/hose replacements are ridiculously expensive
Extensive regional search found no shops that do that type of work anymore
Was being forced into the clamp camp, either screw type or the Oetiker single ear type pictured above (preferred for aesthetics)
However, it appears Doug is vouching that ferrules (sic) will work just fine. I like that option even better. Thx
I am right in the middle of doing three sets of fuel rails and injectors hose replacements.

 

Right. By design no clamps are needed.

The ferrules keep the cut end of the hose from blossoming out with age.

Some guys add clamps as a back-up, so to speak. That's their prerogative.

Once in a great while you'll hear of a leak. I'm sure this is primarily due to damaged barbs or, perhaps, minute production differences in the I.D. of the fuel hoses. The hose-to-barb connection obviously must be a very tight fit, taking quite a good shove to accomplish. I use a smear of silicone paste or similar to ease the shoving-on part.

There was only one time that I experienced a leaking problem and that was when I used Goodyear fuel hose with the very thin blue (nitrile?) inner lining. When pushing the hose onto the barbs the blue lining would separate away and bunch-up alongside the barbs, destroying the fit. Of course you can't see this happening while you're doing the job.

I had to redo all the hoses ! I avoid that type of hose now. In fact I'm not even sure if Goodyear still makes it.

Cheers
DD

 

The OEM ferrules are very tightly constrained by the ferrule. The fir trees on the the metal of these fittings are not the same as those on the fuel rail and injectors. As you can see from the photo on the earlier post, reproduced here, the edges of the fir trees are flat:

I believe that they do need a positive clamp, absent the OEM ferrule assembly. Here is a pic of my lovely new one, recently fitted, you can see how the hose is expanded by the fir tree fitment and how tightly it is captured by the ferrule. Whether this can be reproduced at home, I am not sure. I certainly sleep easier knowing an Oetiker clamp or fuel hose clamp is on any home made fuel connection!

 

Nobody will deny the benefit of sleeping easier . Each of us has different comfort levels and choices to make.

I'll just say, FWIW, that I've always used the same process (and smaller ferrules) on the supply and return lines as I have on the fuel rail and injectors. Works for me !

Cheers
DD

 

Thanks guys as ever for the benefit of your not inconsiderable wisdom.
Ahhhh.......... so the original metal-rubber junctions had what looks like a 'super ferrule' vs. The less chunky version used on the fuel rail hoses.

After due consideration, I think I will go with the 'one ear' clamp type setup as used by the PO. I understand they would have been changed around 5yrs ago and no leaks since, as presumably the car did not burn to the ground prior to my 12 months of ownership.