88 MR2 7 rib block whatever color top, wondering if stock (new) valve springs ok, using 10.5:1 pistoms not planning on going over 7500rpm

256 should work with stock valve springs. do you know the lift of the cams in question?

8.1 mm lift

my engine builder wanted to know if I needed to us eHKS springs and told me he had problems finding aftermarkek springs so if I go with supertech or somebody I can use single springs or is it better to use stffer , double spring set up or is that it over kill

Im not sure but i think that cam will be fine on stock springs. you may be at the limit tho. i think the double spring is more for a larger duration with a more aggressive lift ramp

A 256 cam is actually rather mild. I'd clay it with your high comp pistons to make sure it doesn't contact. Valve float is not because of duration or lift. It happens because of engine rpm. If you're rapping it out to ten grand, the oem springs aren't stiff enough to close before the piston reaches top of rotation. Considering you won't be reving past 7500 rpm's (which was atock rev limiter in my mr2) you should be fine. However just make sure it is timed correctly and clay that chit! Better safe than sorry. Build it right. And best of luck.

the pistons are wiseco 10.5 :1 with Brian crower rods (sports not pro) piston crown was cut pretty deepr valve relief

turns ut HKS doesn't make springs for the 256 cam but do for the others so far from what I see

Its fine, ive used stock springs for 8 years with these cams.

Not to go off-topic... what about HKS springs on stock bigport (or perhaps 256) cams? Overkill? Stock or aftermarket timing belt?

the pistons are wiseco 10.5 :1 with Brian crower rods (sports not pro) piston crown was cut pretty deepr valve reliefrocksteadyracer Posts: 27Joined: Sun Jan 13, 2013 6:16 pm

Did you deck the head? If so then your compression will be higher.

kennyb01 wrote:

the pistons are wiseco 10.5 :1 with Brian crower rods (sports not pro) piston crown was cut pretty deepr valve reliefrocksteadyracer Posts: 27Joined: Sun Jan 13, 2013 6:16 pm

Did you deck the head? If so then your compression will be higher.

MUCH higher......

*IF* it is the piston I'm thinking it is... you are NOT going to be happy... READ the details about the pistons, they say the compression ratio is calculated with a 39cc head... *IF* that is the case... your actual compression will be closer to 12 to 1, then 10.5. This is because a stock 4AGE head volume is 36cc, and once cut it shrinks from there... Do you have any photos of the pistons?

HKS 256 cams have a cam lift of 8.1mm, but a valve lift @8mm or a touch less. GOOD stock springs are fine with the HKS256 cams. Btw... I'm pretty sure the HKS256 is only 7.9mm, the 264 might be 8.1