Practically Classics Forum

hi first time on.can anyone tell me how to check if the valve seats, on my lotus 907 engine, have been converted to run on unleaded petrol ,head is of and camshafts look brand new.

I don't know that engine, but is it an ally head, or cast iron?

If it's an ally head (and I would have thought it was!) then it will have valve inserts in it already, which are almost certainly unleaded-compatible.

Hope that helps...

According to a fella on another forum I wh.. sorry, frequent, who replaced one aluminium-headed, unleaded compatible slant four with another, yes, the 907 is quite happy to run on unleaded without any problems as a result. It'll probably appreciate the 99 octane stuff but needs no lead nor any substitute for it.

The 907 is known for eating its exhaust valves, but that's not a situation that's affected by the fuel used, it's simply a result of the grade of stainless used in the original valves being a little less than stable. I'm told that alternative valves are available, made from a more consistent grade of stainless.

The Jensen Healey was designed to run on what used to be called 2 star, and will run fine on unleaded

2 star was leaded, it's the fact that it has an alloy head and steel seats that allow it to take fuel without lead.....

Luxobarge wrote:I don't know that engine, but is it an ally head, or cast iron?

If it's an ally head (and I would have thought it was!) then it will have valve inserts in it already, which are almost certainly unleaded-compatible.

Hope that helps...

thanks for input better safe than sorry

thanks for all input better safe than sorry