Re: Valve stem seals crushed, LS7. More spring?
Posted: Thu Feb 09, 2017 9:06 am
Kinda.... Finding a good spring for this engine that will fit the spring pockets, with wire that's made in the USA, and getting the loads I want is proving to be more challenging than I thought it would... What makes this difficult, and also unusual, is most who use these rockers on this engine, are not using a hydraulic roller. They're "all in" with a solid roller set up, and lifts are .700+.
I've gotten differing opinions on just how much seat load to target. Open load recommendations are pretty consistent at 450-500, and seeing how I didn't have float before at 470 - I figure that's a good target.
Geoff Skinner tells me 140 - 150 seat, 400+ open.
PAC suggests a minimum of 160 seat load, but to stay under 180.
Martin Smallwood tells me ~180 seat, and 450+ open. Martin has used these rockers on this engine before, several times. I'm inclined to lean toward his suggested loads, seeing how he's got real world experience with similar LS7 builds.
The Ferrea LS spring (that PAC makes for them) rate/loads look great, but they are simply way too proud for those springs. Ain't spending $900 for a set of springs and Ti retainers. At 0.080 coil bind distance, seat load would be 160/173 and 470. At 0.060 CB dist; loads are 169/183 / 480.
I'll most likely just get a set of PAC 1207X's coming and set them up 0.080" from coil bind. Unless my math is off, that's 176/189 seat load, and 466 open.
I've gotten differing opinions on just how much seat load to target. Open load recommendations are pretty consistent at 450-500, and seeing how I didn't have float before at 470 - I figure that's a good target.
Geoff Skinner tells me 140 - 150 seat, 400+ open.
PAC suggests a minimum of 160 seat load, but to stay under 180.
Martin Smallwood tells me ~180 seat, and 450+ open. Martin has used these rockers on this engine before, several times. I'm inclined to lean toward his suggested loads, seeing how he's got real world experience with similar LS7 builds.
The Ferrea LS spring (that PAC makes for them) rate/loads look great, but they are simply way too proud for those springs. Ain't spending $900 for a set of springs and Ti retainers. At 0.080 coil bind distance, seat load would be 160/173 and 470. At 0.060 CB dist; loads are 169/183 / 480.
I'll most likely just get a set of PAC 1207X's coming and set them up 0.080" from coil bind. Unless my math is off, that's 176/189 seat load, and 466 open.
