vavle spring question

[left_34]

My heads are in the process of a port and polish, decked, and 3 angle vavle job... the guy who is doing this told me that i'll need stiffer valve springs or i'll get valve float at 5000rpm.
My question is what kind of springs should i get in order to prevent this.

[brian89gp]

Kinda funny since stock springs are good to 7000.

[SappySE107]

depending on year, yeah. You can shim the springs if you want.

[left_34]

has anyone else here decked there heads... is there anything i need to do after i get this done...?

[SappySE107]

There is nothing to do after you get that done. I have but only to clean up the decking service and make it flush. If you go to far, the engine will become and interference type.

[4spdz34]

i took .020 off each head, there is a side effect though, the more u take off the less room the timing belt tensioner has to take up slack in the belt, so your belt could wear out faster cause your making it too long for the application. its nothing big to worry about.

[Mitch DOHC]

the heads r decked on mine... .and have been for about 20 thousand miles..... no problens thus far

[Juglenaut]

i took .020 off each head, there is a side effect though, the more u take off the less room the timing belt tensioner has to take up slack in the belt, so your belt could wear out faster cause your making it too long for the application. its nothing big to worry about.

A few hundredth of an inch are not going to affect the tensioner or the belt life.

[haasguy]

I decked mine .027 off my heads without any problems. The math says that takes about 4-4.6 cc out of the chamber on my '92 heads.

[4spdz34]

i took .020 off each head, there is a side effect though, the more u take off the less room the timing belt tensioner has to take up slack in the belt, so your belt could wear out faster cause your making it too long for the application. its nothing big to worry about.

A few hundredth of an inch are not going to affect the tensioner or the belt life.

acctually it will cause thats .040 which equals 1 mm, going by gm spec for the measurement of the actuator. if reading is 41.1 mm plus or minus 1.5 mm(1.62" plus or minus .06") the belt is in acceptable range, if it is 45.1 mm plus or minus 1.75 mm(1.77" plus or minus .07") the belt should be replaced. so that 1 mm can mean alot

[left_34]

how much can u take off to be safe.. the site says that .012 gives u a flat surface... if i can take off more than that and be "safe" i would.. did any of u guys notice a significant power increase after u did this?

[4spdz34]

how much can u take off to be safe.. the site says that .012 gives u a flat surface... if i can take off more than that and be "safe" i would.. did any of u guys notice a significant power increase after u did this?

all in all i really couldn't tell, i went from a 115k motor to a brand new motor with ported heads and higher compression, it was a big difference but i can't tell if the shaving did anything. i also went with thinner headgaskets. so i took about .038 off each side if u include shaving and head gasket. i had the ffp chip and if i ran 87 i would get 1 degree knock retard at 6500 sometimes, if i ran 89 i got nothin. but a cold air intake mad it so i didn't have to run 89. and then i tried the 13* exhaust retard, it is great. all i can say is every lil bit helps