Overheating

[Robert Clifford-Wing]

Yesterday taking my eye of the ball, mistakenly I drove my 3 litre for around 20/25 miles with the engine retarded to the mid setting; full advanced is set at about 45 degrees.

The coolant appeard to be hotter than I am used to and, while pulling up a long hill the temperature rose to between 85-90C.

At the top of the hill I realised the error of my ways and returned the engine to its normal 45 degree advanced setting. As my destination was within a few hundred yards, I left the engine to cool down and returned home some time later.

Is my advance/retard setting error the reason for the engine running hotter than usual (70-75)?

[Christopher Carnley]

Retarded ignition is also a cause of overheating.

[Robert Clifford-Wing]

Thank you, I was hope that was the case.

[Stephen Blakey]

There is a bit of a tradition in motoring journalism that when photographing a high performance engine on a test bed, the exhaust manifold should be glowing red hot, presumably to add to the drama of the shot.

As is so often the case, these scenes can be contrived for added effect. This is done by retarding the ignition which increases the exhaust temperature dramatically. It also makes the engine run hotter, as Christopher mentioned.

Retarded ignition reduces nitrous oxide emissions, however with such a low compression ratio yours would be very low to start with (sadly the same can't be said for your CO and hydrocarbons).

I could go on.....

[John Robins]

What about the methane emitted by your horse?

[Stephen Blakey]

Not a problem! I've got a certificate from VAG which shows he's fully compliant with the Euro5 standard, just like their cars.

[John Robins]

I hope his horse pedigree is more truthful than the VAG certificate might have been!