The Hard Facts

Results are now in on the products that can safely let your car run on unleaded fuel. The Federation of British Historic Vehicle Clubs had decided to end the confusion over the unleaded debate by inviting manufacturers of Lead replacement petrol (LRP), Anti Wear Additives (AWA) and in-line Fuel Catalysts to submit their products to scientific tests. The Federation then payed the Motor Industry Research Association (MIRA), a highly respected independent research facility, to run each product through a full set of industry tests, on a Rover A series engine known to suffer from valve seat recession. No petrol manufacturers submitted LRPs for the tests.

Two benchmarks were set, 4 products passed the first test to produce only 0.3mm valve recession after the gruelling test, and only two products passed the reset benchmark of 0.15mm valve recession. Unleaded petrol produced nearly 1mm valve recession while 4 star produced a mere 0.001mm valve recession.

Superblend Zero Lead 2000 and Redline Lead Substitute passed the all tests, while Millers VSP Plus and Valvemaster Lead Substitute passed the first test. As previously stated, no LRPs were submitted and furthermore no in-line devices passed the test, in fact MIRA found that in some cases the valve recession was worst. As a result of the tests the Federation is only putting its backing behind the four products that passed, and Halfords will now only sell these four products.

It may be noted that the Rover engine used would have had softer valve seats than VW engines produced after 1968 (as Ray Christopher informs me is the date VW started to standardise on harder valve seats). But, as a result of these tests the FBHVC and also the club can only confidently recommend these products, or a full engine conversion - but as Ray states, you need to find a garage you can trust.