A bewildering selection of additives promises everything from squeezing more miles out of every gallon of petrol to cleaner engines and smoother running. But which ones work and are they really necessary?
Modern unleaded fuel is made up from a complex blend of refined hydrocarbons mixed with a small percentage (usually five percent in the UK) of ethanol. Fuel is sold by its octane rating and the Research Octane Numbers (RON) for commercially available petrol in this country is a minimum of 95 RON for ordinary unleaded and 97 RON for premium fuels such as BP Ultimate or Shell V-Power.
Unleaded fuel, or 98 RON four star, was withdrawn from UK forecourts on 1 January 2000. Owners of older cars were then left with a serious dilemma of either having to have harder valve seats fitted to their car’s cylinder head or dosing every tank of fuel with a lead-replacement additive such as Castrol Valvemaster.
Although refineries add MMT (methylcyclopentadienyl manganese tricarbonyl) to unleaded fuel to boost its octane level, lead replacement additives act as a substitute for the small amount of tetraethyl lead that was first added to motor spirit in the Twenties to stop engines suffering from pre-ignition or knocking.
Pre-ignition is when the compressed fuel/air mixture in the combustion chamber ignites before the ignition sparks and over time, severe knocking or pinking can seriously erode the valve seats and the engine components.
この記事は Classics Monthly の Issue 260 版に掲載されています。
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この記事は Classics Monthly の Issue 260 版に掲載されています。
7 日間の Magzter GOLD 無料トライアルを開始して、何千もの厳選されたプレミアム ストーリー、8,500 以上の雑誌や新聞にアクセスしてください。
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REINVENTING THE PAST
This may well be the newest car you ever see featured in Classics magazine, but we hope you'll agree that Morgan's 21st Century return to three-wheeled motoring is pretty close to being an instant classic.
AN MG RARITY
The MkIII and MkIV Magnettes have forever lived in the shadow of their illustrious forebear, the Z-Type Magnette. Sales were never strong and scrappage rates were high, but fans are now seeking out and cherishing the few that remain.
Out on the road again
I was in a great rush as usual when I checked out the Allard P1 late one evening, only to find that the lights wouldn’t come on main beam.
A CHEEKY CHAPPY
The Austin A30 and later A35 are tiny by today's standards, but back in the 1950s they were everyday transport for many a family. With all the charm of a puppy they had a tendency to worm their way into owners' affections, and Ray Lewis' lovely 1957 example is no exception to this rule.
Light Fantastic
We revisit Audi’s cleverly engineered lightweight loss-leader. Just don’t mention the A-Class.
Prized Companion
Originally the second prize in a national driving competition for lady drivers, this Escort XL is now a cherished family heirloom.
Exhausting Gentry
At the beginning of August I was in Denmark attending the 2017 Copenhagen Historic Grand Prix and as usual this was a brilliant event.
Major Minor Screen Problems
The last few weeks have been taken up with fettling the Minor’s wipers, as the motor was running too hot, despite smoothing the bends in the outer and replacing the grease with EP90 oil.
10 Things You Need To Know About... Bmc 1100/1300 (1972-1974)
For a car that was Britain’s best seller for most of its 12-year production run, the BMC 1100 and 1300 are remarkably scarce with survivors being just a tiny fraction of the two million plus cars that were produced between 1962 and 1974. Built in both Cowley and Longbridge, demand for the 1100 was so great that even after Longbridge started building the Austin version in late 1963, the Cowley plant had double shifts working to build enough cars.
Project MGF
Last month saw us going right through the MGF’s cooling system and since then I’m happy to report that the garage floor seems to have remained bone dry.
