Changes in lubrication oil additive packages, increasing engine temperatures and the increased use of alternate fuels place greater demands on rubber components inside the internal combustion engine. The rubber valve stem seal, positioned in the valve train, may respond adversely to these changing conditions. Two elastomers, a copolymer, (TFE/P), and a terpolymer, having a similar propylene backbone molecular structure, (T/P/T), have been studied for their functional advantages over the standard fluoroelastomer, (FKM 1).
The data presented in the paper compares the effects of various crankcase oils and crankcase fuel dilution on valve seals produced from each of the three materials. Both the TFE/P and T/P/T show improved chemical resistance over FKM 1.