i just installed a set of tfs tw 185's with an f cam with 1.6 rollers and i'm trying to figure out what length pr i need. tfs states that rocker fulcrum center should be 1.150 +/- .050, that aint gonna happen in this life time, i'm way under that. tfs also says the length should be 6.750 +/- .050 at 6.750 i just about run off the valve stem, so much for that i don't know hgow they can even say that without knowing what rockers you're using. they also say to keep the witness mark under .080 and if it's off the valve center line sliightly its ok. well after much agravation i got the following results and am looking for input as to which length to run.
valve center line is .170 all results with 5/8 turn preload
intake / exhaust
pr length/ witness mark/ wm centerline/ witness mark/ wm C/L
6.500 .120 .150 .095 .162
6.550 .090 .135 .075 .160
6.600 .080 .120 .070 .155
6.650 .070 .115 .055 .142
sorry about the numbers layout but it's i could manage here
as you can see i'm running quit a bit towards the exhaust side of the stems but if i go with any shorter of a push rod the witness mark gets to be excessive and at .450 the rocker just starts to touch the bottom of the studs.
i'm think about .550 's on the exhaust and .600's on the intakes but that would mean i'd only have .080 of the stem left before the rocker would come off the stem opn the heel of the lobe.
i really need some input from someone with more expierence in this area than i have
thanks alot guys
valve center line is .170 all results with 5/8 turn preload
intake / exhaust
pr length/ witness mark/ wm centerline/ witness mark/ wm C/L
6.500 .120 .150 .095 .162
6.550 .090 .135 .075 .160
6.600 .080 .120 .070 .155
6.650 .070 .115 .055 .142
sorry about the numbers layout but it's i could manage here
as you can see i'm running quit a bit towards the exhaust side of the stems but if i go with any shorter of a push rod the witness mark gets to be excessive and at .450 the rocker just starts to touch the bottom of the studs.
i'm think about .550 's on the exhaust and .600's on the intakes but that would mean i'd only have .080 of the stem left before the rocker would come off the stem opn the heel of the lobe.
i really need some input from someone with more expierence in this area than i have
thanks alot guys
