Thread: What fuel do i use

Although these motors only need bog standard fuel, it's not a good idea to leave that sitting in your tank for long periods because it can turn funny. If you're not using the vehicle all the time, pay a little extra and use 95.

My attitude has always been to use normal fuel and not worry about the additives - my MGBs all had cast iron heads and weren't built for unleaded. The thought was that if the valve seats pounded out, it wouldn't be a major hassle to get the head rebuilt with hardened seats.

As it happened, the black GT was my only vehicle for over three years and the head never gave me a problem (actually, that car never gave me a problem). Nor did I notice that I was having to adjust tappets any more often than you'd expect. My last MGB was going to be treated like that, but I took off the piddling down draft Weber and fitted twin SUs, then gave her a good thrashing in hills... and the engine let go - actually, nothing broke, the builder called it the most worn motor with nothing broken he'd ever seen. Interestingly, the valve seats were fine and I couldn't imagine the previous owner even being aware of additives, let alone using them. Naturally, when rebuilding the motor, we fitted hardened seats and over the next 13 years, she didn't give me a problem.

I'm sure others will give conflicting advice and they may have a point however, if you accept that one day you'll need to rebuild the head, which is likely anyway, don't worry about it. On the other hand, it doesn't kill anyone to use an additive if they want.

This engine was designed to be tolerant of fuel quality, and will perform satisfactorily on anything you can buy here (caveats apply on over 10% ethanol).

While it is sometimes suggested that a lubricating additive is needed if running on unleaded, it should be pointed out that this engine was sold in Canada for a number of years when leaded fuel was unavailable, withoout any factory or dealer requirements. I have run mine on unleaded for over ten years with no signs of valve seat recession (shows up with tappet clearances decreasing over time). General experience seems to be that this engine only has concerns with unleaded petrol when worked flat out for sustained periods, such as frequent long distance freeway driving. In any case, if valve seat recession does occur, the head can then be fitted with steel valve seats, and further problems are eliminated.

Note that for the best performance, the ignition timing will need to be adjusted for the particular fuel octane used, and if this is changed it will need adjustment.

John

I run mine on premium unleaded, 95 or better, or avgas when I can get it,
no problems at all, it runs well, starts on key without playing with pedals, usually I start when standing outside the vehicle with just turning the key, one or two compressions and she is ticking over.
it doesn't seem to matter what time of year, she just does it this way.

Avgas. There's a story there, it's not as though it's available at most servos.

series landies with spark plugs run on any fuel you can pump from a bowser that doesnt contain the words Diesel, kerosene, tur.

series with glow plugs run on those three.

for longevitiy of certain parts you are best advised to stay away from E10+ fuels but feel free to run it if its what you can get so long as youre going to top up with <E10 from a nearly empty tank on the way home.

Originally Posted by crackers

Avgas. There's a story there, it's not as though it's available at most servos.

I don't buy it at servo's, in fact, I don't buy it at all.
sometimes it must be discarded due contamination