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Discussion Starter #2
Let me add on some more info...

Let me add on to the above. I have a clicking noise and i believe it is valve float. Some of you may remember i had this issue a while back and i thought it was just the issue of adjusting the valves but I have ruled out that isn't it. I run stock valve train except for a cam which has .450 adv lift on it and I'm starting to think my 30 something year old springs can not keep up with that amount of lift. I'm in the market for some new springs but have a few questions....

1) Single or double springs
2) What kind of spring rate should i be looking for and is too much bad?
3) Will a higher spring rate mean thicker diameter coils? Will this cause coil bind?

Thanks-Blake
 

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A lot of that depends on the Cam and who makes it, and what RPM you will turn with it. I had a 480 lift chevrolet cam that only had 350# open rate.:eek:

If you know who made the cam, ask them for recommendations. Coil bind is almost impossible with .450 lift unless you have too long of a pushrod or an enormous shim pack to boost spring pressure. Your ticking noise could be many things, but I doubt valve float is the culprit. That ordinarily happens at high RPM where your springs can't push the valve closed in time and they are all open to a degree when they should be seated. Once you've heard valve float, you don't forget it.

1) Single or double springs
Single for a driver with that kind of lift. I would run a beehive spring before I would run a double on a street car.
2) What kind of spring rate should i be looking for and is too much bad?
Again, check with the cam maker. And YES too much spring can be very bad.
3) Will a higher spring rate mean thicker diameter coils? Will this cause coil bind?
Some are thicker but still way below coil bind at 450 lift


Check your rockers for wear
Check your valves for correct lash
Check your studs to see that they are not pulling out of the head
Check for exhaust leaks
Make sure your rockers all move the same amount to rule out a bad lobe
Make sure it's not something in the bottom end.:(
Make sure all your pushrods are straight
Good luck!
 

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As for the stock springs used in a 400, I wouldn't even want to guess. Probably pretty lame. Probably about a 300 lb rate. Around 80-90 lbs on the seat and 250 lbs open.
With that small of a cam, you could probably get by with the 98214 springs available here.
http://www.competitionproducts.com/products.asp?dept=419

No need for any crazy expensive wiz-bang hardware for a .450" lift cam.:no:

Just so you don't get the terms confused. The spring RATE is how much pressure the spring exerts in 1" of movement. You'll sometimes see the spring rate advertised as lbs/in or pounds per inch.
Seat pressure is the amount of pressure the springs are exerting at their installed height (no lift).
The "OPEN PRESSURE" is basically calculated by YOUR installed height pressure plus YOUR total lift (Varies by spring rate).
For example, if your springs are set up at 1.700" installed height with 125 lbs of seat pressure, and you know your spring's "Spring rate" of 300 lbs/in and you have .500" lift, then your open pressure is 275 lbs.

or

300 X .500 + 125 = 275

This becomes valuable info when selecting spring for the more sensitive applications like aggressive hydraulic rollers and solid flat tappets especially.:yes:
Ex: I need 140 on the seat (installed between 1.85" and 1.90", slightly adjustable by adding to removing shim, different retainers, locks, etc.) and 375 open (@ .617" lift) to control my valves at 7500 RPM. There's a multitude of springs that will fit the first part of the criteria (seat pressure), but very few fit all of it correctly!!

Hope this helps.
 

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Discussion Starter #6
Thanks for the good info. Just to let you know it does not do it at idle but only at 1800 RPMS and up and gets progressively worse. I'll try to post a video for some reference. I ordered the springs "D-Man" mentioned. Wasn't to bad on my wallet so if that doesn't fix the issue then i guess its something else. :rolleyes::(
 
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