Club Triumph

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

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!!!

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.

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

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.

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

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

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



  

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