QUESTION
Back in 2005 I purchased a Weber braided fuel hose from Lotus Marques for my Elan.
With all the discussions about ethanol mixed to fuel and possible damages I wonder, whether the above mentioned fuel hose is ethanol proof and if so, whether there is an age limit.
W.W. - Switzerland
ANSWER
In 2005 there were not many manufacturers who anticipated that Lotus vehicles would be operating on ethanol blended fuels.
The advice surrounding the recommend blend ratios is not concise when considering what is safe when fuel passes through existing rubber hoses.
It is generally accepted that a 10% ethanol blend is safe to use with rubber hose manufactured to SAE 30R6.
The braided hose supplied for your Weber carburettors is manufactured to SAE 30R6 and should be suitable for E10 fuel.
However if you want to use E85 fuel then it is recommend that your Elan fuel hose should be changed and fitted with a hose manufactured to SAE 30R9.
Generally hoses manufactured to this specification have a PTFE inner liner construction that is totally resistant to ethanol.
It is understood that current legislation may influence you in changing to use ethanol based fuels.
Be aware that your Lotus twin cam engine was never designed to operate on ethanol fuel and it maybe necessary to change the mixture and ignition setting.
Until such time there is sufficient historical data about Lotus twin cam engines being dyno tested and operated on ethanol blended fuels, we recommend using pure petroleum.
As a matter of interest, Lotus Marques has a close working relationship with a local specialist machine shop that has ISO-9000 certification.
This same business operates Ford Australia engine repair/exchange program for its dealers.
There have a number of different engines pass through this workshop that have common problems of high oil consumption.
Investigations have revealed several of these engines have been operated on ethanol based fuels.
It appears the combustion bi-products had contaminated the lower oil control rings with a sticky varnish that prevented the rings from sealing correctly.
The solution to this has been to clean the pistons, fit a new set of piston rings, re-assemble the engine and return it to service where it has continued to operate reliably.
This information is still being collated and I expect some conclusion will be drawn from this emerging this trend.
I fully understand your concerns about a fuel hose used by date but I have never seen any manufacturer publish data about fuel hose life expectancy.
I am not a chemist and I don't work for a hose manufacturer, however I can share my experience operating a specialist Lotus workshop.
Based on what is observed on a regular basis, it is suggested that rubber fuel hoses may have a service life of 20 years.
However there will be exceptions based on use, type of fuel, ambient temperature, external case contamination etc.
It would be prudent to change fuel hoses every 10 years just to be safe and prevent any possibility of a fire.
It is also recommend that the original fuel line that runs through the Elan chassis be changed - all of these hoses have a used by date!
Copyright © 2013 Lotus Marques
Back in 2005 I purchased a Weber braided fuel hose from Lotus Marques for my Elan.
With all the discussions about ethanol mixed to fuel and possible damages I wonder, whether the above mentioned fuel hose is ethanol proof and if so, whether there is an age limit.
W.W. - Switzerland
ANSWER
In 2005 there were not many manufacturers who anticipated that Lotus vehicles would be operating on ethanol blended fuels.
The advice surrounding the recommend blend ratios is not concise when considering what is safe when fuel passes through existing rubber hoses.
It is generally accepted that a 10% ethanol blend is safe to use with rubber hose manufactured to SAE 30R6.
The braided hose supplied for your Weber carburettors is manufactured to SAE 30R6 and should be suitable for E10 fuel.
However if you want to use E85 fuel then it is recommend that your Elan fuel hose should be changed and fitted with a hose manufactured to SAE 30R9.
Generally hoses manufactured to this specification have a PTFE inner liner construction that is totally resistant to ethanol.
It is understood that current legislation may influence you in changing to use ethanol based fuels.
Be aware that your Lotus twin cam engine was never designed to operate on ethanol fuel and it maybe necessary to change the mixture and ignition setting.
Until such time there is sufficient historical data about Lotus twin cam engines being dyno tested and operated on ethanol blended fuels, we recommend using pure petroleum.
As a matter of interest, Lotus Marques has a close working relationship with a local specialist machine shop that has ISO-9000 certification.
This same business operates Ford Australia engine repair/exchange program for its dealers.
There have a number of different engines pass through this workshop that have common problems of high oil consumption.
Investigations have revealed several of these engines have been operated on ethanol based fuels.
It appears the combustion bi-products had contaminated the lower oil control rings with a sticky varnish that prevented the rings from sealing correctly.
The solution to this has been to clean the pistons, fit a new set of piston rings, re-assemble the engine and return it to service where it has continued to operate reliably.
This information is still being collated and I expect some conclusion will be drawn from this emerging this trend.
I fully understand your concerns about a fuel hose used by date but I have never seen any manufacturer publish data about fuel hose life expectancy.
I am not a chemist and I don't work for a hose manufacturer, however I can share my experience operating a specialist Lotus workshop.
Based on what is observed on a regular basis, it is suggested that rubber fuel hoses may have a service life of 20 years.
However there will be exceptions based on use, type of fuel, ambient temperature, external case contamination etc.
It would be prudent to change fuel hoses every 10 years just to be safe and prevent any possibility of a fire.
It is also recommend that the original fuel line that runs through the Elan chassis be changed - all of these hoses have a used by date!
Copyright © 2013 Lotus Marques