Valve spring questions?

[underatree]

Hey there guys I have a few question's about valve springs.


The cam I am going to buy needs new valvesprings of course.And I don't know alot about the subject.Here are the specs there lunati.

Cams a lunati voodoo
219
Exhaust Duration at 050 inch Lift: 227
Duration at 050 inch Lift: 219 int./227 exh.
Advertised Intake Duration: 262
Advertised Exhaust Duration: 268
Advertised Duration: 262 int./268 exh.
Intake Valve Lift with Factory Rocker Arm Ratio: 0.468 in.
Exhaust Valve Lift with Factory Rocker Arm Ratio: 0.489 in.
Valve Lift with Factory Rocker Arm Ratio: 0.468 int./0.489 exh. lift
Lobe Separation (degrees): 112




Valve Springs, Single, 1.266 in. Outside Diameter, 462 lbs./in. Rate, 1.060 in. Coil Bind Height,


I plan on installing them on a set of 461's I have.

Will this require me to get screw in studs?

Are they the same diameter as a stock spring?Well the area under the spring be big enough or will need to be machined?

How hard is it setup valvesprings?What tools will I need?Is this best left up to a machine shop?


Thanks for any advice.

[veno]

here is a pertty good read and step by step that PATMAN wrote up

http://www.bracketracer.com/engine/dartheads/dartheads.htm

[underatree]

That is definitly a good write up.Did he ever get around to finishing it?I didn't see a link.

So far I'm not scared.I have 2 motors to build in the next few years.As well as who knows how many in the future.So learning all I can is a must.Buying the tools and learning will save money in the long run.

Also if these springs are the same size as the stock one's does that mean I can use the same retainers?

[patman]

That was a few weeks ago, I'm still waiting for a chance to get back to that and do the final assembly...some day soon when I get a round tuit. My car time lately has been taken up with ordering the final (!) odds and ends for the new engine/trans. Water pump...alternator...starter...plumbing...plugs...w ires...that sort of stuff. Now that I'm broke again, I should get back to actually assembling all the bits I have accumulated.

The key is that the springs are the right height. That means the distance between the spring pocket and the retainer. If the current retainers work out to the right height for your new springs...and they fit on the springs correctly...should be fine.

[underatree]

Alright thanks...

What about the issue of the springs being to hard and causing the stud to pull out.Sure I know I would be better off getting screw in studs.But are they mandatory with this type of spring?

I am kind of assuming this springs are still close to stock specs.The cam I am ordering has under .0500 lift.Nothing wild.

Also I have heard of putting little pins in the studs to keep them from pulling out.Any experince with this?

Patman thanks for the info and that write up is nice.Looks like your a pretty smart fella.

[underatree]

I have been doing a little comparision on just how hard these springs are.
These are the springs lunati recomends for the this cam.

Valve Springs, Single, 1.266 in. Outside Diameter, 462 lbs./in. Rate, 1.060 in. Coil Bind Height,

This a comp cams recomendation from comp on a similar cam.


Outside Diameter of Outer Spring (in): 1.254 in.
Coil Bind Height (in): 1.150 in.
Damper Spring Included: Yes
Spring Rate (lbs/in): 370 lbs./in.
Inside Diameter of Outer Spring (in): 0.880 in.
Valve Spring Style: Standard
Coated: No
little stiff compared to some of the other's I have found.


There pretty similar.But why does lunati want a spring that has 92 lbs./in.More presure than Comp?

Seem like with who cam flattening thing going on I would want softer spring pressure..I plan on use Rottella oil in.And maybe some other break in lubes.

I guess I need to call comp or lunati and make sure I am getting the best package.

[D-Man]

Flat tappets usually don't like more than 350# of total ACTUAL open pressure. The seat pressure will vary depending on what the cam manufacturer thinks will keep the valves from bouncing/floating (how fast the ramps are). Harold has made the Voodoo series lobes pretty fast so Lunati is specifying a bit more pressure than some.
To calculate YOUR ACTUAL open pressure take the spring rate, multiply it by YOUR lift and add your seat pressure.
That's why you'll see 100 different spring with the same installed dimensions (1.25" OD, 1.55" OD etc..)...so you can set your seat pressure and choose the proper spring rate to achieve the optimum open pressure (or as close as possible).
If it all becomes too confusing, find a COMPETENT (I stress that because there's a lot more "parts changers and hacks than TRUE head shops that actually know what they're doing!!) head shop to set them up for you.

[underatree]

I have another question fella's so any help would be great.I plan on ordering this stuff wednesday.


Last night when I was looking a different cam,Springs,Retianers,ETC.

I noticed this cam is ground on a 112lsa.So I started reading and it seems the main reason why they would grind it on on a 112lsa is for vacaum.Is this correct?If not then why.

I am putting this cam in a vehicle that is just a play toy and it has manual brakes.Manual transmission also.So if don't have alot of vacaum.That isn't a big deal.

I also noticed that I can buy a similar speced comp cam.And get all the components with it for about 130 bucks less than lunati.So I have started to shift to a comp 280h.



Thanks for any advice.