ITA 240 Compression Ratio

[crs240sx]

I have heard that Nissan lowered the compression ratio on 240's early in the first year of production.

Can anyone verify this?

My shop manual says 9:1, but a friend told me that they were produced with 10:1 pistons for the first few months.

[handfulz28]

I think it was just 9.5:1, but yeah, early motors had the higher-compression pistons. That's why the ITCS show 9.5:1 for the SOHC/ITA.
Michael
ITA #09

[Pete Smith]

The 9.5:1 pistons you're talking about are avaiable through Nissan Motorsports and are in the catalog, and come in std and .40 over.

[crs240sx]

Thanks for the info.

Corey

[crs240sx]

Can somebody verify whether the the 9.5:1 shown for the ITA 240 in the ITCS includes the allowed .5 over stock.

In other words, is the max compression allowed 9.5 or 10 to 1?