Low comp 1168 piston ID?

[imago]

Anyone able to identify these low comp pistons? They may be suitable for the draw through but I'd want to use new rings so need to know what make they are.

 

[Duckndive]

from the no they may be Cosworth 

if you measure the ring grooves Wiesco have ring sizes on there site

 

[imago]

Just now, Duckndive said:

from the no they may be Cosworth 

if you measure the ring grooves Wiesco have ring sizes on there site

 

Thanks, I'll get them measured up tomorrow. 

If I can get the rings organised I can get a set of barrels bored to suit and save the 10.25-1 Wiseco pistons and bores for a normally aspirated engine. Seems a bit of a waste to stick a shim gasket on the base to make high comp low comp if there's an alternative.

[Gixer1460]

How do you 'know' that they are low comp? They don't look to have a complete dish or is that raised portion just a photo artifact? It wouldn't need much of a thicker head gasket to make the 10.25's work in a blown application as they'd be classed as low comp for a NA build.

[imago]

16 minutes ago, Gixer1460 said:

How do you 'know' that they are low comp? They don't look to have a complete dish or is that raised portion just a photo artifact? It wouldn't need much of a thicker head gasket to make the 10.25's work in a blown application as they'd be classed as low comp for a NA build.

Standard pistons are flat, as are wiseco, MTC have a slight rise, these are concave. So without changing the stroke these are lower compression by default. Once I have the barrels and head off of the other ET I can get an accurate measure of both these and the Wiseco to work out what the actual ratio is.

Absolutely lowering the comp with the Wiseco is possible, although I'd shim the barrels off of the cases rather than at the top. However if I use low comp pistons instead I'll have a ready to go 1168 kit for the next engine. 

[imago]

A bit better pic of the fish.