Need advice on valve springs

lennyjay

Well Known Member
I have an older (but brand new) Comp Extreme cam pn #48-000-5 - grind# 409 6054/6055. This is a solid lifter cam.
I have the Comp solid lifters also new. The motor is a Chevy 1964 409 ci. 11:1 with 690 heads, Crane 1.70 gold rollers and 4-speed.​
I would like to know what valve springs I could use (part number) and if beehive or a dual spring setup is the best. RPM range to 6300​
This is taken off the cam card:​
Lobe separation is 110.0, lift is .554 int and .569 exh.​
Valve adj at .012 intake and .012 exhaust​
There is no valve spring recommendation nor can I find any information on this cam. I have called Comp cams and they can't find any info either. They said it was discontinued and not carried in the catalog.​
I may take it to the strip, but more street and car shows.

Thanks for your help.​
 

Fathead Racing

Well Known Member
Supporting Member 7
I’m sold on the Beehives. From a mild performance build, like yours they are great. I use mine with solid rollers. The intended use would be with hydraulic lifters. I chose Beehives for my street strip engine because they are easy on the valve train. If you know your installed height and spring pocket diameter call Comp Cams for the correct spring.
 

Don Jacks

Well Seasoned Member
Supporting Member 3
If you're running stock length valves,your assembled height should be right at 1.67.If you go with a single spring with damper[cheaper],you may need to open up or enlarge the spring pocket.Do not deepen this area just enlarge it.These heads are kinda thin in this area,hence the deeper pockets being cast into the later 583 head.
 

lennyjay

Well Known Member
I checked a couple spring pockets and they sit at 1.582-1.584. They are not cut down in the head, very little. The heads may have had some work done on them already. I have dual springs now, but do not know the specs on the springs. The springs have a red stripe going down each, and I don't know what that indicates (could be a manufactures mark?). I better check the length of the valves to be sure. The stems are 3/8.
What is the standard length for the valves if I may ask....?
 

El Rat

Well Known Member
If the spring is larger (at the bottom) you can grind a taper on the bottom coil. Just grind enough to get the spring to fit the spring pocket. Remember it’s a taper.
 

Skip FIx

Well Known Member
You can add longer valves. Various BBC can work and they come in various extra lengths. Always double check coil bind. And check it your self. 40 years later I figured that was why my 409 broke rockers, then finally dropped a valve. Machine shop was supposed to have checked that-but I was a high school kid and did not know better.

And yes I still have those springs and Crane ALUMINUM retainers!
 

lennyjay

Well Known Member
I have been going around with this "installed height" for springs on my 690's. I have just the 1.680 installed height to play with. I want to run the stock valves lengths, so no longer valves now. Below I found a formula to determine if I take a taller installed height spring and bring it down to the 1.680 height. The figure below is an example, but you can see where you could put a lot of seat pressure (and assuming open pressure) on your cam, thus wiping it out. Taking even a 1.750 installed height spring and squeezing it down could stack the coils and cause coil bind if not checked along the way. I am trying to get around 110-125 lbs seat and no more than 320-350 lbs open. If I am all wet, or over thinking this, please pipe in and add what you think..........Thanks.....

Formula:
The same formula can be used to determine the closed pressure because most manufacturers seldom list the free length of the spring to calculate with. If we move from a 1.750 installed height to a 1.700 with the 350 lb./in. spring rate it would work out as .050 x 350 = 17.5, which when added to the 100 lb. figure at 1.750 would now give a closed pressure of 117.5 or roughly 118 lbs. If we were increasing from the 1.750 height to a 1.800, then you would subtract that amount which would produce 82 lbs.
 

boxerdog

Well Known Member
Supporting Member 5
Most of the cam/spring manufacturers publish tables showing all of the relevant spring info. It's kinda fun to put them in a spreadsheet and compare them directly. You can pretty much ignore the free length if you have all of the other data.
 

lennyjay

Well Known Member
Yes, you need installed height, seat and open pressure, along with spring rate and you can fine tune the spring selection. The over all max lift on the springs is a give away. When you find the springs that will work, then finish off with the correct rocker geometry and last the push rod length for intake and exhaust.
 

boxerdog

Well Known Member
Supporting Member 5
Here's an old example, not sure if it is accurate but it shows one way of looking at it.
 

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