I hear Jaguar Cars have Starmotor and leaded petrol is still essential for them. What is a star motor/Engine?

Answer 1

Certainly not in the USA. You can't even get leaded fuel here. And having worked with children affected by lead poisoning, it's a good thing that they stopped it.

I think there may be an additive that can be purchased for use in classic cars, but I don't know whether it actually has lead in it, or some other compound that works as a substitute.

Start your research at: http://www.jaguar.com
A web search for "starmotor" turned up some dealers that go by that name, and some northern european sites, whose language I am not able to read.

Answer 2

I've never heard of Starmotor.
Jaguar's engines have had names like XK and AJ.
The ability to use unleaded fuel has been a requirement in the USA since the 1970s, and in Western Europe since about 1990 (although many cars were unleaded compatible from the mid-80s).
A modern car with a catalytic converter cannot use leaded fuel - the lead poisons the catalyst.
An old Jaguar (pre 1988) might still need leaded (or lead-replacement) fuel, but not newer models.

Answer 3

Much ado was made in Britain with the switch to unleaded gas, most of it is needless worry. In the US, we've had experience with this since the late 70's. For the most part, there's no impact. Even with old fashioned cast iron heads and soft valve seats, the motor will usually wear out before valve recession is a problem. The exception would be if it's run extremely hard, as a race motor or a truck used for towing. Jaguar, in particular, has used aluminum heads with hardened steel seats for at least forty years. They are the least susceptible motors to valve recession damage from unleaded fuel.

Answer 4

Some very old Jaguars that have not had their heads modified to run on unleaded fuel require leaded petrol, or unleaded with an additive. This is needed to stop the valves buring out.

All recent Jaguar cars run on unleaded or diesel fuel.