ethanol......is it bad?

[Richard Farrant]

Originally Posted by Hanno Spoelstra

Indeed, lead was not added to car petrol until after WW-2.

A number of SAE tests (incl. one on Army vehicles) proved that the wear on valve seats and valves with unleaded petrol is not noticeably higher (compared with leaded petrol) if the engine is operated under 3,000 rpm.

My own opinion is that the latter is a good tip, as 1940s and 1950s MV engines are rarely operated above 3,000 rpm. over long periods.

hi Hanno,

I must just comment on the first use of "lead" in car petrol. It was General Motors in the USA who came up with it in the early 1920's and produced the additive with an oil company. It was Tetra ethyl lead, or TEL. It was added to petrol in the UK in the early part of 1930's, I think from memory that you could buy petrol with or without. During WW2, in UK, TEL was added again for military use, in such large quantities, that it actually produced valve problems, and a number of modifications had to be done to engines of military vehicles during the last part of the war.

When leaded was phased out in the UK, a number of lead replacement additive were marketed here and laboratory tests were done at the motor industry research site, using BMC A series engines, the top performer being one called Superblend Zero 2000, which I have used ever since. The fact about engines running below 3000 rpm and not heavily loaded not suffering, was also made during the tests. As it is, I have not come across any noticeable rise in vehicles with valve problems, not like it was in years gone by, when decokes and burnt valves were a common occurance.