Valve springs.....

I know this has been hashed and rehashed but i have a 500 lift cam 785 at valve with 296 duration we plan on turning 9000 max my suppier sent me a spring that will be 450lbs at install am i wrong in thinking this is too much pressure?

 

If this is a Hemi... no its not too much

 

You also have to take in to account how much blower your running. You don't need that much spring if your only running 25lbs of boost. But if your running a screw with 40-50 lbs, you'll need that much spring to be safe. Of course the intakes are more important than the exhaust side.

 

Alright 450 seems to be alright buy what i have found it is a hemi what is the thinnest shim i can put under it to protect the head? I need to run like a .015 to keep pressure down will this work or will it just break up ?

 

can you run a different height keeper? if so, do that with a little thicker shim....just a thought.
Darren

 

It seems as though you are worried about spring pressure- your quote about keeping pressure down? As for installed height there are posts in here to give the details on proper installed height which determines how much shim to run under them. I wouldn't worry about 'too' much spring pressure. I would WORRY lots about not having enough. 450 is ok. Not enough spring pressure will cause all sorts of problems for you. PM me and I will give you my phone number or call Mike Canter. Dave Germain

 

Is there a spring cup?

 

By today's standards 450# is pretty low.

 

No spring cup brad 4 heads 2.130 from head to retainer with no shim at all springs say 2.200 installed height 1.200 coil bind valve lift is .785 less .028 lash so do i worry about pressure because the way i figure it which may not be right is that i will need to shim to get coil bind correct but at 2.130 these springs have 450lbs ?

 

Sorry coil bind is 1.142 not 1.200

 

Do the springs contact directly to the alum head or can someone explain this to me?

Help the hemiless!

 

Thats what i am trying to figure out the previous measurements were from the bare head no shim to the bottom of the retainer

 

Here's the way I fugure out to set the spring height.....
1.140.....Coil Bind
.765.......Lift
.060.......from Coil Bind

Add 'em all up: 1.965". you can set them at 1.965 with out worrying about coil binding. If that's too much spring pressure you can put them in at more height.

 

NO!!!
put at least .015 shim in there

 

I am looking at the numbers and I am not sure if you have the right springs for your application. If my calculator isn't lying to me it looks like you will need .156 worth of shims. With a .785 lift minus .028 lash you have
.757 lift at the valve- This was actually measured with a dial indicator? If not it would be safer if you did. Use some soft checking springs and mount your dial indicator so it reads right off the retainer. Now with a coil bind of 1.142 and safety margin of .060 you have a total stack of 1.959. You said you had 2.130 under the retainers minus a .015 shim to protect the heads. This works out to 2.115-1.959= .156 of shims required. Not an impossible amount of shims but a shorter valve would be better or a thicker spring cup under the springs? Believe it or not you will get a lot longer spring life and beat your valve train up a lot less if you install the springs like this. I truly can't remember the last time I installed valve springs at the manufacturer's recommended installation height. Dave Germain

 

Ok so here is the run down see what ya think 500 lift cam i measured it last night and the rockers are 1.5 dont know what to think of that but the car ran great last year with the same cam rocker combo. So i have 750 at the valve less lash is aprox 725 the spring i have is way too much i think so i am ordering a spring with 350lbs @ 2.100 and cups for under the spring that are .60 thick i think so that will bring the pressure up some around 400lbs i hope the coil bind height is 1.160 and i will be at 1.315 max lift . Will this coil bind height get taller if i shim the valve spring because the 1.160 is advertised with the 2.100 installed height i am hoping it will and if i still have excess coil bind clearance i will shim till i get it tighter does this sound better ? I think the 370lb springs @2.200 are too much for my application i will be running around 36lbs of boost and stay around the 8500-9000 range in rpm so i feel as if the springs get around 425-450 installed pressure it will be fine