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garyf
July 15, 2016, 12:39pm Report to Moderator

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Can anyone recommend the best modern Fuel to use in the Lucas PI System?

I've been having trouble with the rubber seals failing in the Metering unit and Dizzy pedestal, even though the Metering Unit was fully reconditioned only 3 or 4 years ago?

I have used Shell V-Power before in my Vitesse and it did seem to run a bit smoother than your normal supermarket fuel?

Any advice welcome.

Gary

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Ridgetone Triumph
July 15, 2016, 1:36pm Report to Moderator


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When I ran the race car I found the only fuel suitable was aviation fuel at 120 odd octane..Good stuff. But believe it or not for normal road use I found Tesco 99 the only fuel that worked for the engine and injection system. I did try others but had running issues with most. I had a good squirt of Baby oil with every tank full as well. I had the race car on the road here for about 9 years and no issues with the Tesco stuff.    The secret is in the right brand of baby oil, don't use cheap stuff!!!


1973 Triumph 2.5 PI Estate on su's, awaiting plans Hmm maybe I'll leave him as is
1981 Triumph TR7 V8 DHC��work now started work now stopped work started again work stopped again work started again work stopped again   work started again   work stopped again   work started again work stopped again   work started again  
1971 Triumph 2000 Sport
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thescrapman
July 15, 2016, 1:38pm Report to Moderator

Colin Wake
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Now there is a very good question....

Any PI Triumph likes Octanes, so anything 99 is good. (Incidentally, if you go to Germany, try some Aral 102, it is like rocket fuel, especially after a tweak of the timing)

But if it gets the Octanes via ethanol then maybe not so good.

Identifying a specific make is also fraught with danger, as the blends from different sources of the supposedly same fuel may contain different levels of ethanol.

I would try a few tanks of Tesco 99, that seems to work for me, not had any seal issues on the 2 PI cars that have drunk it longer term, both of which have had rebuilt injectors and metering units. The latest PI car looks like it is having issues with 30 year old seals, I have an appointment to see Neil Ferguson tomorrow at the TRR International to discuss.

You can get a set of seals from Neil and reseal your metering unit yourself if you want to be sure it has the latest ones fitted.


Schadenfreude expert and collector of assorted rusty Triumphs on the Essex/Suffolk Border.

2010, 2011, 2013, 2015 and 2016 CT Navigators Championship winner.

10CR 2005, 2007, 2009, 2011 2013 - RBRR 1990, 2006, 2008, 2010, 2012, 2014, 2016 - Nachtrit 2006, 2007, 2008, 2009, 2012 - Chinese rally 2007, 2008, 2009, 2010, 2011 - HCR 2009, 2011, 2012, 2013 (3rd place), 2014. 2015, 2017

On the road.
1968 Spitfire Mk3 : 1973 TR6 : 1967 Herald 1200 Estate 1970 : 1968 Mk1 2.5PI 1968
Off the road
1967 Moss Monaco (Mk1 GT6 based) : 1970 Spitfire Mk4 : 1970 Mk2 2000 auto  : 1964 Mk1 2000  : Mk2 2.5PI
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JohnD
July 15, 2016, 2:54pm Report to Moderator


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Oh, nonsense!

"Octane number" is the ratio of a mixture of iso-octane and n-heptane that has the same antiknock characteristics as the fuel in question, in a test engine, under conditions specified by British Standards (MON Motor Octane Number) or the American Society for testing andf materials  (Research Octane number), the conditions differing slightly.   While some other parameters, such as temperature and humidity will affect it, by far the major limiting factor is CR.

The Triumph Pi cars were designed when "5-star" petrol was available.  That was 100 octane, and the cars had a CR much less than the knock limit for even 100 octane fuel.   The TR6 Pi and PI saloons at 9.5:1.    That fuel relied on tetra-ethyl lead to achieve that level of anti-knock and other compounds are used now.    There is absolutely no point, benefit or purpose in running a car with a compression ratio less than 11 on 120 octane.   You would do better to raise it some more to 14+ and use ethanol fuel, otherwise any improved performance is in the mind of the driver.

Having said that, I run SofS (2L, Pi, CR 10.75) on Shell Nitro-V, at 98 octane, which is fine, but if the fuel is less than fresh, it pinks.

For the OP, the modern antiknock and lead substitute compounds are lethal to ordinary rubber, as anyone competent to recondition a metering unit would have known well 3-4 years ago.    They should have and would have used Viton seals.
Best not use 'supermarket' fuel, that can be most variable in recipe, but try a well-known brand and stick to it.

John


Serial Vitesse racer.

Old Blue.  1995-2001
Silverback. 2001-2007
SofS. 2007 - to date.

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garyf
July 15, 2016, 4:01pm Report to Moderator

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Quoted from thescrapman
Now there is a very good question....

Any PI Triumph likes Octanes, so anything 99 is good. (Incidentally, if you go to Germany, try some Aral 102, it is like rocket fuel, especially after a tweak of the timing)

But if it gets the Octanes via ethanol then maybe not so good.

Identifying a specific make is also fraught with danger, as the blends from different sources of the supposedly same fuel may contain different levels of ethanol.

I would try a few tanks of Tesco 99, that seems to work for me, not had any seal issues on the 2 PI cars that have drunk it longer term, both of which have had rebuilt injectors and metering units. The latest PI car looks like it is having issues with 30 year old seals, I have an appointment to see Neil Ferguson tomorrow at the TRR International to discuss.

You can get a set of seals from Neil and reseal your metering unit yourself if you want to be sure it has the latest ones fitted.


Colin

PM Sent

Gary

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Ridgetone Triumph
July 16, 2016, 9:32am Report to Moderator


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Quoted from JohnD
Oh, nonsense!

"Octane number" is the ratio of a mixture of iso-octane and n-heptane that has the same antiknock characteristics as the fuel in question, in a test engine, under conditions specified by British Standards (MON Motor Octane Number) or the American Society for testing andf materials  (Research Octane number), the conditions differing slightly.   While some other parameters, such as temperature and humidity will affect it, by far the major limiting factor is CR.

The Triumph Pi cars were designed when "5-star" petrol was available.  That was 100 octane, and the cars had a CR much less than the knock limit for even 100 octane fuel.   The TR6 Pi and PI saloons at 9.5:1.    That fuel relied on tetra-ethyl lead to achieve that level of anti-knock and other compounds are used now.    There is absolutely no point, benefit or purpose in running a car with a compression ratio less than 11 on 120 octane.   You would do better to raise it some more to 14+ and use ethanol fuel, otherwise any improved performance is in the mind of the driver.

Having said that, I run SofS (2L, Pi, CR 10.75) on Shell Nitro-V, at 98 octane, which is fine, but if the fuel is less than fresh, it pinks.

For the OP, the modern antiknock and lead substitute compounds are lethal to ordinary rubber, as anyone competent to recondition a metering unit would have known well 3-4 years ago.    They should have and would have used Viton seals.
Best not use 'supermarket' fuel, that can be most variable in recipe, but try a well-known brand and stick to it.

John




1973 Triumph 2.5 PI Estate on su's, awaiting plans Hmm maybe I'll leave him as is
1981 Triumph TR7 V8 DHC��work now started work now stopped work started again work stopped again work started again work stopped again   work started again   work stopped again   work started again work stopped again   work started again  
1971 Triumph 2000 Sport
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griffipaul
July 16, 2016, 12:20pm Report to Moderator

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Used to use Tesco momentum in my tr6  ran ok on it , but got fed up of going to garage and they did not have any or pump not working -became a common occurrence. So switched to Shell v power - much better - low speed pick up seemed improved . Just back from CLM put about half a tank of French 98 in  , did not seem to run so well , some hesitancy  - but may have been something else - who knows .
By the way keep a track of my petrol costs working out at 19p /mile
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garyf
July 18, 2016, 2:35pm Report to Moderator

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I've had a reply back regarding the ethanol content in Shell Nitro:-

Dear Gary,

Thank you for contacting Shell.

Currently, in the entire UK, the Shell V-Power Nitro+ contain ethanol up to a maximum of 5% volume as compliance to the BS EN 228 standard for petrol.

I hope this helps and should you need further assistance, please feel free to revert back to us.

Best regards,

Rachelle
Technical Helpdesk - UK



  
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GT6 M
July 18, 2016, 4:31pm Report to Moderator

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Thats fust time ive seen Shell actually admit their fuel contains Ethanol,

as a while ago, they would no say.

As far as Im aware, only BP and Esso are free of the stuff.
this only the higher octane stuff.

BUTT, no in the South, and no in Scotchlandshire, I was told by their PR dept ages ago.

oot of curioisity, when I have ever filled up wid Tesco 99, 10% eth,
then wen on comp screen read oot,  I can see ECU adding fuel to the idle, 4 -6 % extra.

not so much so wid the Shell, maybe only 1 - 3 % at idle
normal BP, as in me own toon, then its  deducting  5- 7 % all the time

M


One does not have to know how a thing works, to know that it is not working right

Ye div,nt efta no ooa thing wuks, t,no its nut wuk,n reet.







Scaryport,��Cumbria,.
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Andymoltu
June 29, 2017, 9:52am Report to Moderator

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Unless the metering unit was rebuilt with a set of very old seals it should not be the modern fuel causing the problem.
Early unleaded contained a lot of benzene and other volatile compounds that were damaging to the rubber seals in the metering unit. Current fuel is less aggressive.
However the usual suppliers of seals and rebuilders of PI kit have known of the issue since the early 90s and supplied unleaded compatible seals, presumably made of Viton or similar.

Have you checked your fuel pressure? Over-pressuring can damage the metering unit.
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Andymoltu
June 29, 2017, 9:52am Report to Moderator

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Unless the metering unit was rebuilt with a set of very old seals it should not be the modern fuel causing the problem.
Early unleaded contained a lot of benzene and other volatile compounds that were damaging to the rubber seals in the metering unit. Current fuel is less aggressive.
However the usual suppliers of seals and rebuilders of PI kit have known of the issue since the early 90s and supplied unleaded compatible seals, presumably made of Viton or similar.

Have you checked your fuel pressure? Over-pressuring can damage the metering unit.
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