: 8000+ rpm



ponyboyt
08-04-10, 12:52 PM
VSS goes bad over 120ish km/h, some times get wonkey shifts... a friend and i and my car and his cherokee with an R/T package... car downshifted from 3rd at about 165... ouch... 700km later and no issues, no noise, still perfect :worship: but was a scare nonetheless. Im starting to wonder at my RPM gauge now, its always shifted right at the 7k rpm line (in 2), all my other ones shift around 6500.

Ever seen a an rpm guage be off like that?

Submariner409
08-04-10, 02:09 PM
WOT FWD Northstar shift rpm is about 6,300 - 6,400 level ground normal load.
IF your engine were upshifting at 7,000 you're at or past the point of valve float
and severe engine damage: the stock valve springs in the flat tappet cam follower
engines just will NOT handle high rpm, and to try and increase spring pressures EATS
stock cams and followers.

ponyboyt
08-04-10, 03:46 PM
guage has to be wrong then. That and the combination of the flakey VSS must be what made it down-shift. There is no loss of power whatsoever when it shifts. Code free car, so gonna have to look at some other diagnostics. As for engine failure.. nope, runs strong and quiet. Maybe the needle is just lazy?

Will's Fiero
08-07-10, 02:13 PM
WOT FWD Northstar shift rpm is about 6,300 - 6,400 level ground normal load.
IF your engine were upshifting at 7,000 you're at or past the point of valve float
and severe engine damage: the stock valve springs in the flat tappet cam follower
engines just will NOT handle high rpm, and to try and increase spring pressures EATS
stock cams and followers.

Do you have any examples or threads showing what happens with high load springs and the stock cams/buckets? Are these experiences with CHRFab springs/retainers?