Hi Ezrider

Funny you should bring that up !

I hate this unleaded fuel! Its gummed up my garden strimmer and lawnmower as well, it just causes rust everywhere.

It trashed the fuel pump on my Celebration Jag and the inside of the fuel tank was so full of rust, that I had to have it professionally cleaned right down to bare metal and a new pump and sender.

Cost me nearly a 'grand' to have it put right!

But the Jag that had been layed up for 8 years, has never had anything in it other than 'Leaded Fuel' and when I pulled the sender out to have a look inside, the tank was as clean as a 'whistle'

So where the heck in the UK can I still buy leaded fuel now?

Does anyone know?

 

Before you cause their marketing people to get a case of swollen heads, it's almost certain that any brand of oil would have given the same results. As part of my professional career, I got to oversee all sorts of aircraft engines that had been sitting unwanted and unloved for years- for all sorts of unbelievable reasons in locations ranging from warehouses to jungles in countries I couldn't find on a map.

After witnessing dozens or hundreds of teardowns, it became evident that the only real issue was corrosion to non-oil wetted components. In each and every case, there was a surprising amount of residual oil still clinging to surfaces inside the engine, not much different than an engine that had been shut down for an hour or a day rather than a decade.

Oil brand made no difference.

I'm due this summer to fire up two of my old toys that have not been looked at since 1996. That should be an adventure!

 

Which certainly makes me think twice about the oiling ritual I go thru prior to firing an engine that hasn't been run in several years.

I guess it's been more of a 'feel good' thing than actually making any meaningful difference.

I can't guaratee that I'll stop doing it, though

Cheers
DD

 

You can use Castrol Valve master, not that wear to the valve seats/stem is a concern at all on this engine, to raise the octane level. Or you can slightly retard the timing of the engine (by about 3 degrees) IF you cooling is good to appreciate the lower RON (95) fuel.

Personally I just whack in the additive. But yes modern unleaded with its ethanol content is horrible stuff, turns to varnish is just over a month and ganks everything up. As for Magnatec - its bit of a marketing gimmick, oil performs according to its viscosity ratings (hot / cold). The only thing that semi-synth / fully synth bring to the party is longevity as they tend to resist heat degradation significantly better than mineral oils. Castrol charge enough in the UK for their stinking 4 LITRE bottles as it is - don't encourage them

 

I'm not too sure about that Mikey, Magnetec is supposed to have Molysulphides in it to reduce friction and they way that engine fired up on just a couple of spins of the starter, I'm a believer!

Nothing but Magnetec for me from now on.

Who knows, they might even send me a case of the stuff!

 

Hi Doug

Castrol can do no wrong in my eyes, after my recent experience and the Magnetec was a bargain, when on special offer and now I'm glad that lack of space prevented me from going through the pre-oiling saga.

There is no way I'm using the cheap stuff in such a beautiful engine, you usually get what you pay for.

As for the fuel, I've found what I think may be the best unleaded on the market.

Tesco Momentum 99 octane 5p per litre more than normal unleaded, which seems to stack up against the price of having to put in additives.

And I also get Tesco Club Card points, so that's a bonus!

 

I believe your car was designed to run on 95 RON fuel. Your owners' manual will say for sure. If so, you will gain NOTHING by using fuel with an even higher octane level. There is no need for additives of any type.

 

Hi Mikey

Its supposed to be specially formulated to reduce engine wear, so the way I see it I've nothing to lose except for an extra 5p a litre and considering this is a Summer car and not for everyday use, that won't add up to much extra.

If it says 95 Octane in the owners manual, which it may well do (I haven't looked yet) They would surely have been referring to leaded Petrol, in which case that may have been fine.

But this dreaded unleaded stuff for me is a game changer, so that is why I am going to use this 99 Octane stuff.

 

Hi Mikey

As you don't seem to be a fan using Magnatec, it would interesting to see how long it takes your 'Toys' to fire up.

Maybe there is no difference but it would be quite a useful experiment all the same for both of us.

 

I have nothing against Magnatec at all, I'm sure it's a good product. Oil type or brand has no bearing on how long it takes for an engine to fire up. I suppose viscosity might cause a variation in cranking speed, but then it would be marginal. My S-type (when being driven year round) would crank at virtually the same speed at -30C as at +30C.

 

maybe I am misinformed on the ethanol amounts in UK fuel but the problem isn't leaded or unleaded it is the amount of ethanol in the fuel that causes it to gum up.

The XJS is not designed for leaded fuel

the lead acts as a cushion for the valvetrain, but not everything is made with higher quality materials and it is not necessary. Leaded fuel has lead added to it, it is not inherently less prone to gumming and turning to ****.

If you are going to leave your vehicle for a while put a fuel stabilizer in it to prevent the gas going bad or remove the gas all together.

 

@ side. The RON of old 4star (leaded) was closer to 98, Unleaded in the UK now sits at 95. I believe any running issues arise (if they in fact do arise) due to the disparity in the amount of "bang" per litre, not so much the presence/absence of lead. Hence the need to adjust timings or use additive. I know that my 85 HE hates modern, unadulterated unleaded and runs lumpy if used. I also know the previous owner used 4 star without any issue whatsoever


But you are 100% right to say that their is no need to protect the valve train on any XJS engine with lead.

 

yeah not very familiar with the way gasoline is setup in europe. Here the highest octane runs best and is what is recommended in the XJS and pretty much all fuel contains up to 10% ethanol which is what causes the most problems as far as gumming.

We have a website that shows the top tier companies for gas based on their additive system and mine runs great using those fill stations (mainly Shell).


If you are saying the older style leaded gasoline also had a higher octane rating then definitely that makes sense, the lead is unrelated.

 

Just for reference:

Octane ratings in no way reflect any characteristic of fuel other than resistance to detonation/pinging/pinking. It has nothing to do with how much cleaning additives may be present or any sort of measurement of energy content, burning speed or temperature. There's tons of myths on this subject.

Octane levels in North America are not directly comparable to the rest of the world, there are two different rating scales in play. Our '91' is labelled '95' in the rest of the wrold.

Using fuel with a octane level higher than specified by the OEM will not increase performance, nor is it a guarantee of having more additives of any type, nor are they needed or of benefit. If Jag says that 95RON is recommenced, that's it. Anything more is waste with zero return.

Neither Jaguar nor their former parent company Ford endorse the Top Tier marketing scheme.

Save your money.

 

Hi Sidescrollin

I cannot agree that 'The XJS is not designed for leaded fuel' when the XJS came out leaded fuel was the only stuff around.

I've got a couple of scrappers that I bought for spares and one of them has got carbs! and inside the tank there is no sign of rust whatsoever!

 

I agree its the ethanol that is the problem, so using the highest octane, should certainly help to make my car run better than using Ron 95.

 

Indeed. But given the H.E's high compression ratio it naturally lends itself to a high RON fuels, which may explain why mine does not like the green stuff straight out the tap.

 

Cars produced for the US market from '76 onwards had, by law, to be compatible with unleaded fuel. I'd be surprised to learn that cars designed after that point in time would not take this requirement into account or that a decision was made to produce two versions of the same engine. I think a similar requirement came about in the UK around 1992ish (?)

If the car is indeed not unleaded compatible, what do drivers in the UK do to get around the problem since leaded fuel has not been available for 10 years or so?

If we accept for a short moment that ethanol does have demonstrable side effects, using a higher grade of fuel will change nothing as most/many premium fuels contain 10% ethanol as it's a cheap and effective way to boost octane ratings.

 

All the Jag V12s had hardened valve seats, even in the 70s, thus the leaded fuel was never required. I'm sure that's what Sidescrollin was referring to in saying "...not designed for leaded fuel...".

I'm pretty certain that Jaguar starting using hardened valve seats in the old "XK" type 6 cylinder engines in 1968.



Cheers
DD

 

its defiantly the ethanol that causes fuel isues much more quickly not the lead. ever sense the ethanol became wide spread in the us. fuel that has sat for 4 month's looks and runs as bad as fuel that has sat for 5+ years before ethanol.

now as far as draining a tank before storage, your actually better to top the tank before storage. even if you have to drain stale fuel out when you drag it back out. the reason for this is rust. a empty tank has room for condensation to form and rust your fuel tank from the inside out. its easier to drain stale gas from a tank then to de-rust or replace a tank.