Spec me new valve springs on 720' lift setup
11-11-2020, 08:40 AM
#21
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Anyone feels free to enlight me on what springs would be better. I thought maybe Manley Nextek 221421 btu they have less springs rate (435) but a little bit more open (515) and installed (165) pressure, and more lift rated 800'. They do have more room for coil bind at .900 insteat of 1.000 with the Pac,
How much pressure/load is too much?
Just swap em out and be ok with it?
How much pressure/load is too much?
Just swap em out and be ok with it?
As you noted, the spring has a low spring rate, but lots of travel. This gives it a higher seat pressure even at similar open pressures when compared with other springs like the 1209x. For me, beyond the cam, the considerations are the rocker ratio, the weight over the valve tip of the T&D (not a jab at the product, just as compared with stock rockers), and also the weight of the valve come into play. The ramp rate on that cam should be about 46 degrees, which is aggressive, but not like full-sausage-solids-aggressive.
I have seen high enough spring pressures to break the tip of the valve clean off, but you're not in that territory. You don't have to worry too much about spring pressure on your heavy side, because you're running solid lifters (nothing to compress) and you're running 3/8" pushrods.
I think what I would do in your shoes is get the manley nexteks you're looking at, shim the spring to get to a net .790 lift (.070 shim), and that will get you increased spring pressure to help with the T&D's tip weight and still stay below 600 lbs of open pressure, so the valve tip should not be a concern. This will increase your seat pressure as well, which is where I think you'll need the most control on this setup. Really you could go to .080 shim because you'll lose .010 due to lash as the engine warms up. Also with the nexteks, make sure to get the matching set of retainers and keepers.
11-11-2020, 11:33 AM
#22
2. Followed recommendations of the guy who ran this cam and had stellar results
3. I asked TSP, FED and some other people at that time that I trusted and just followed their advice.
4. This is a follow up after a season and I am looking for advuces and stuff and I am open minded.
5. This is ls1tech, not callyourpartsmanufacturer.com
6. I did send an email and got an answer from Cam Motion and they said the 1209x is their fav choice for low lash setup, but usually recommend to run it with .700' or less. So its a start.
7. Cam Motion tech guy is talking about 1238x, but as I thought, a lot of pressure will put stress on everything and anything can break at anytime. Remind you, my car is a street car.
7. Thank you for all the replies. LoL
11-11-2020, 11:38 AM
#23
I'm running those springs. They work good, but I don't have a lot of hours on them. What hours they have is very hard duty. Motor went to 8K on it's break-in dyno
As you noted, the spring has a low spring rate, but lots of travel. This gives it a higher seat pressure even at similar open pressures when compared with other springs like the 1209x. For me, beyond the cam, the considerations are the rocker ratio, the weight over the valve tip of the T&D (not a jab at the product, just as compared with stock rockers), and also the weight of the valve come into play. The ramp rate on that cam should be about 46 degrees, which is aggressive, but not like full-sausage-solids-aggressive.
I have seen high enough spring pressures to break the tip of the valve clean off, but you're not in that territory. You don't have to worry too much about spring pressure on your heavy side, because you're running solid lifters (nothing to compress) and you're running 3/8" pushrods.
I think what I would do in your shoes is get the manley nexteks you're looking at, shim the spring to get to a net .790 lift (.070 shim), and that will get you increased spring pressure to help with the T&D's tip weight and still stay below 600 lbs of open pressure, so the valve tip should not be a concern. This will increase your seat pressure as well, which is where I think you'll need the most control on this setup. Really you could go to .080 shim because you'll lose .010 due to lash as the engine warms up. Also with the nexteks, make sure to get the matching set of retainers and keepers.
As you noted, the spring has a low spring rate, but lots of travel. This gives it a higher seat pressure even at similar open pressures when compared with other springs like the 1209x. For me, beyond the cam, the considerations are the rocker ratio, the weight over the valve tip of the T&D (not a jab at the product, just as compared with stock rockers), and also the weight of the valve come into play. The ramp rate on that cam should be about 46 degrees, which is aggressive, but not like full-sausage-solids-aggressive.
I have seen high enough spring pressures to break the tip of the valve clean off, but you're not in that territory. You don't have to worry too much about spring pressure on your heavy side, because you're running solid lifters (nothing to compress) and you're running 3/8" pushrods.
I think what I would do in your shoes is get the manley nexteks you're looking at, shim the spring to get to a net .790 lift (.070 shim), and that will get you increased spring pressure to help with the T&D's tip weight and still stay below 600 lbs of open pressure, so the valve tip should not be a concern. This will increase your seat pressure as well, which is where I think you'll need the most control on this setup. Really you could go to .080 shim because you'll lose .010 due to lash as the engine warms up. Also with the nexteks, make sure to get the matching set of retainers and keepers.
and just get the -.050 locks and be done with it!
11-11-2020, 12:36 PM
#24
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That's a really good way to do it! I'm not sure if the manley locks come with -050. In fact they might be +050. I simply don't remember.
11-11-2020, 03:28 PM
#25
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Call Cam Motion ask 4 Steven or Bobby ..
They need 2 no the Lobe numbers for your cam. Which generally are the: example Cam reads 5408/6808 hr 113+4
5408 is the intake lobe the 6808 is the exhaust.
They will give you the recommended springs for your cam and recommended seat and open pressure. So then u could pick your own.
This Message is brought to you by Smokey B.
Rule #278564. U must have a recommendation for springs if you purchase a cam. Which includes seat and open pressure.
Not just, oh it says .700 max lift for springs and my cam has 680 lift. Yeah that sounds great. 🤔
That's BS and the incorrect way to purchase valve springs.🤫😉
They need 2 no the Lobe numbers for your cam. Which generally are the: example Cam reads 5408/6808 hr 113+4
5408 is the intake lobe the 6808 is the exhaust.
They will give you the recommended springs for your cam and recommended seat and open pressure. So then u could pick your own.
This Message is brought to you by Smokey B.
Rule #278564. U must have a recommendation for springs if you purchase a cam. Which includes seat and open pressure.
Not just, oh it says .700 max lift for springs and my cam has 680 lift. Yeah that sounds great. 🤔
That's BS and the incorrect way to purchase valve springs.🤫😉
Smokey B, he has 4000 miles and 200 passes on previous solid roller spring setup....which still runs great, just down on power a little. Absolutely nothing wrong with the spring choice here.
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G Atsma (11-11-2020)
11-11-2020, 05:07 PM
#26
0.080 on the Manley would give an open pressure of approx 549lbs@1.020 (80x0.435 load/inch+ 515lbs open pressure@1.000). I would have bigger margin on the wear and keep the right press on the springs.
Right now with the 1.780 installed height, the PAC are around 520lbs@1.080 open press (20x0.500lbs/inch +510lbs open press@1.100)
Maybe its only a matter of wear on components, so the installed height is now greater and putting less pressure on the springs..I'll keep you posted
Last edited by Johnnystock; 11-11-2020 at 05:16 PM.
11-11-2020, 07:08 PM
#27
I took it as he has a cam and doesn't know which springs 🤫 if what he has worked needs a bit more (shim it) or higher rate pressure spring as not 2 lose as much and or lighter valve train.
My dumb 🐴 🤐.
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Che70velle (11-11-2020)