20v valve springs

[AceSniper]

what is the limit that stock valve springs can take? iv been told 9mm lift (re grinds) would prolly need new springs? but I want to be sure coz of the cost
cheers

[ChaosAD]

ask your cam grinder. can you get the 20v cams reground to 9mm?

[AceSniper]

well the specs I have work out to 9mm guess its possable with shims....

[RedMist]

Its all to do with acceleration. Which can be a combination of duration, lift and the lobe profile.
For instance a 310 degree 9mm lift cam MAY work (although I doubt it) where as a 270 degree 9mm lift cam MAY NOT work.

Hence you need to check with your cam grinder.

These aren't Franklin cams bought off VVega are they?

[vvega]

they were run with stock springs before so i dont see why it would be a issue now

v

[RedMist]

10k20v ran them with stock springs. However thought that with high RPM he should have shifted to an aftermarket spring.
I do know that they were rev'ed quite hard and appeared to have no gauling of the lobes so I'd say they should be fine.
Did you get the valves to use as templates? (although you shouldn't need them)

[AceSniper]

thanks umm think they work out 274 9mm in and 290 8.9mm ex, while kelford thought they should have new springs, I didnt get much of an answer from franklin (from memory will have to look at emails)

[Celica RA45]

have a mate that is running a std ecu and motor with 10.8 mm cam and 30degrees more at 50 thou and seems to be fine this is off a billet thou and is a waggott cam grind profile

[10k 20v]

hmmm, i could possibly be persauded to part with my TODA Racing valve springs.
Unused and still in the box

The specs for those cams is 284 in (230 @ 50 thou) and 9.1mm lift
304 ex (240 @ 50 thou) and 8.9mm lift