K series - Forged or Cast pistons?

[Andrew Willcox]

I understand my 1.6 K series has forged pistons from it's racing life but I have no documented history to confirm it.

I currently have the head off and was wondering if it is possible to confirm the pistons are forged based on the crown geometry?  Would to reassuring to know what I'm working with.

Can anyone tell me how to distinguish?

Thanks

[Richard Price]

If the engine has had forged pistons fitted to an engine sealed for racing, then they are likely to have flat tops (apart from valve cut outs). Standard pistons have a shallow dish, but forged pistons normally have a higher crown to increased compression ratio with a dish. But the crown is machined off to maintain the same compression ratio.

[Andrew Willcox]

Thanks Richard, they must be forged with machined tops as you describe.  Good to know!

[oilyhands]

AFAIK there is no forged piston fitted to 80mm bore K series engines that has a raised crown, the normal Omega pistons have a shallow dish and larger pockets than the stock cast pistons. Some times these forged  pistons are machined flat on the top when fitted to 1600 engines to prevent contact between piston and head. The size of the pockets is an obvious way to differentiate them.

Oily