TFS strongly recommended using only viton valve stem seals on their TW head(the plain rubber ones that come with a gasket set you generally throw out). Their rationale was the TW head rotated valve guides needed more
oil to work properly, and avoid premature wear. I've always used PC teflon insert, or Crane all teflon valve stem seals. Using the TFS rationale, all canted valve engines would need this.
I aquiesed on this one and installed the viton seals. Now the engine uses about a quart of
oil every 1000 miles. Contemplating replacing the seals with teflon insert, or all teflon. Experiences and recommendations please.
TFS tech support thinks that perhaps the seals have pulled loose, or the guides may be worn.
Engine is warm street 351W, moly rings, KB hypereutectic pistons. Comression ratio 9.8:1. Cranking compression 175#. Engine has 14,000 miles of mostly commuting and highway use.
Oil is
synthetic 10W30. Engine should not be using any oil.