WARNING - PERISHED FUEL HOSES

 

THIS IS A POTENTIALLY LETHAL PROBLEM

 

A few years ago, Adrian replaced the main fuel hoses that run from the
Bosch fuel distribution block across the bulkhead to the fuel filter.
 
He also replaced the small hoses that T-off to feed the 7th injector.

 

 

A few months later, he started the car and opened the bonnet to find
fuel spraying everywhere!
 
Turns out that although the hoses he used looked fine at the time, they appeared
to have cracked and perished badly, having been heated by the exhaust
  system that runs dangerously close to the Tickford fuel components.

   

 
Not immediately obvious until you flex them!

 

It turns out that there is much more to this story concerning
hoses and their compatibility with modern fuels!
 
In recent years the ingredients included in the petrol we
put in our cars has changed.
 
Various Ethanols and Oxygenators have been added to make
 fuel cleaner and more efficient.
 
Unfortunately, these additions to Petrol are chemically aggressive and
have a tendency to infiltrate and attack the rubber compounds
historically used to make fuel hosing.
 
These rubber components perish, swell and crack under the

    influence of Ethanol and ultimately fail.

 
Additionally, early fuel hoses were designed to be used with
carburetted engines and rated to around 50psi pressure.
 
Modern fuel injected systems can typically run at anything
up to more like 100psi.
 
The Society of Automotive Engineers (SAE) specify the strict
requirements that fuel hoses have to meet.
 
The 1980s / 1990s standard was known as SAEJ30R6.
 
Modern fuel hose should meet SAEJ30R9.
 
 
The table below shows their differences:
 
 
  Standard Permittivity Working Pressure  
         
  SAEJ30R6 600g/mē/day 50psi  
         
  SAEJ30R9 15g/mē/day 100psi  
         
         
R9 fuel hose has been designed to work with modern fuels
and has less than 3% of the permittivity of
1980s and 1990s fuel hose.
 
The high permittivity of older fuel hoses means that as the bio-Ethanol
content of Petrol rises then the older grades of fuel hosing will
rot / perish / crack / weep at an increasingly quickening
rate from the point of installation.
 
This is because the escaping vapours 'wash out' the synthetic rubber
compounds that help keep the fuel hose supple - the ensuing
brittleness enables cracks to develop in the hose.
 
 
The industry has a growing problem with fake hoses being
imported from the Far East.
 
 
 
Genuine hose should have the manufacturer name and inner bore diameter marked
along its length together with the SAE standard
 
 
In other words, if it came from China with no markings on the outside
and cost 50p per metre - don't touch it with a bargepole!

 

While we are on the subject of fuel hoses, a note about fitting them..........
 
 
One of the properties of Rubber materials is their elasticity or in other words,
their ability to be stretched and recoil back to their original shape.
 
This elastic spring force acts with the natural friction generated between
the fuel hose and metal pipes when rubber fuel hose
is stretched over them.
 
This generated grip, under normal operations will hold the fuel hose
in position on the pipes.
 
 
 
 
The magic number for the amount a hose should stretch is 10%
 
 
Finally, use a good quality clamp to secure the hose.
 
 
   
Spring clamps are recommended for fuel hoses Jubilee clamps are also acceptable

 

Many thanks to volksbolts.com for the above information about

fuel hose standards and how to fit hoses correctly

 

Now given that fire is a real risk with the Tickford Capri, it makes sense
to consider some kind of fire extinguishing system.
 
Adrian has gone for an electronically controlled LifeLine system that shoots
 two streams of Zero 2000 extinguishant into the engine bay.

 

   
Nozzle 1 fires forward and covers the Bosch distribution system Nozzle 2 covers the fuel filter and 7th injector area
   
   
 
The 2.25 litre bottle is bolted under the glovebox and does not get in the
way of the passenger's feet
 
The two lines carrying the extinguishant run through the heater cowl on the
bulkhead - very fiddly as you need to remove the heater box and do some
upside-down drilling, but it makes everything invisible
 
 
 
The control box is mounted to the left of the steering column and the wires run through
the blank on the lower dash panel where the choke is fitted on standard Capris

 

LifeLine systems are available from Merlin Motorsport
who are based at Castle Combe:

 

 

The LifeLine system is race-approved so is ideal if Adrian decides
to take his car to a track day in the future!