Fiat TC 1438 & unleaded fuel

[eddie]

Can anyone tell me if the 1438 TC engine will run on unleaded without too much ill effect? I use Australia's premium which is 95 octane. I have also been using one of those valve protector add in's with each tank. is this necessary?

thank you

[Guy Croft]

I'd maybe carry on with the additive, as the ex valves used in that early motor are not 21-4n stainless like the later engines, just alloy steel. I just dug out some from a 1438 that I kept out of interest. I don't think the valve seats were ever changed, I think they kept the same high grade cast iron throughout the 8v TC range. Mark you, the valves and seats are so old - unless they have been dressed up recently, that there will be a lot of distortion on them anyway. That said I suppose if it runs well and the valve clearances are OK it is not argument for accelerating the valve/seat distortion & wear, which unleaded fuel certainly will. The best additive I presonally ever used was Redex.

For interest, the later OE ex valves, introduced with the 132 series - one piece stainless and stellite coated contact face, very good on unleaded, but the coating gets quite a battering from carbon, sulphur particles etc in service and doesn't, like everything else in an engine - last forever. Moreover if the valves are refaced, the coating is lost.

GC

[sumplug]

This topic we have discussed on the Sporting Fiat Club Forum.
Basically, we concluded that most of the alloy headed Fiat engines can run unleaded. But if the engine is old as not been overhauled, run it with additives. Redex or Millers is good. For high compression engines like 130 Abarth, run that on Super Unleaded with additives.

Andy.