Thread: Built 4t65e - The results are in.

Originally Posted by JamesIvey24

The torlon check balls tend to "conform" to any irregularity in the valve body a little better than the hard steel balls, might stop some seepage under pressure.

This, and to reduce/eliminate separator plate wear. I've been told it's possible for the steel balls to actually beat their way clean through the plate. It would take a long time though. Here's what I found while searching the web:

"Sonnax check balls 10000-08 (.250") are made out of tough, wear-resistant imidized plastic. The Sonnax imidized plastic balls seal better than steel balls because they conform to the separator plate ball seats. Steel check balls are hard and heavy, wearing separator plate ball seats from the repeated high impact of the ball on the seat. Elastomer or rubber check balls seal well. However, the elastomer material wears, reducing the size of the ball. Similar imidized plastic balls have been used on some original equipment late model valve bodies with excellent results. These imidized plastic check balls are not available through the original manufacturer."

Imidized plastic is the generic term for the trademark name Torlon.