Valve springs when should I change them?

velardejose · Post by **velardejose** » Mon Jul 14, 2008 1:15 am

Hi
When should I change the valve springs in a stock config?
Thanks in advance

Post by **Ash** » Mon Jul 14, 2008 2:13 am

when the valves start bouncing round like big titty's!

just for general interest,

Camtech performance valve spring that came with me stage 4 cam, Holden blue/red motor whichever one i don't know? and standard E15ET springs. i reckon the Holden springs are quite a decent choice for these engines. as long as they aren't worn out totally

they did a good job with my old Crow stage 3 cam and some very spirited driving / 8,000 rpm burnouts!

BQ.05.TD · Post by **BQ.05.TD** » Mon Jul 14, 2008 8:37 am

i think fj springs fit as well. but makes them a inner spring

thre are a heap of other springs that will fit out of a shit load fo diffrent cars

valve springs lose 50% of there tension after about 2 years any way, so after 25 odd years its prob a good thing to replace them, but in saying that you prob wont feel any diffrence if you do change them

raddavey · Post by **raddavey** » Mon Jul 14, 2008 2:18 pm

i've got some springs from some BMW engine in mine.
My stock springs were only seating 30lbs so now i have 80lbs with the bmw springs.

velardejose · Post by **velardejose** » Tue Jul 15, 2008 1:49 am

Hi
30 lbs seating?
31 mm diam exh valve ~1.17 sq/in
Asuming preturbo exh pressure double the intake pressure
14 psi intake pressure
28 psi exh preturbo pressure ~32.7lbs against the exhaust valve trying to go back
My e16 fsm says 51 lbs seating pressure, and asuming it lost 50% of its tension after 'n' years, it has ~26 lbs
My carb has a black soot inside the throat, and it doesn' come from the turbo (leaks a tad oil but its not black)
Would like to hear your comments
Thanks in advance

raddavey · Post by **raddavey** » Tue Jul 15, 2008 2:57 pm

yeah i thought it was a bit low when they told me but that's what the head shop measured. That's the pressure on the seat so with the valve open there would be more pressure. But it wasn't valve floating on 19psi that i noticed.