Exeeding valve spring rate
10-19-2014, 09:04 PM
#1
Exeeding valve spring rate I have a machine shop working on my heads and making me a cam. I have pac 1237x rated at 700 max lift, now the cam lift is 760 and going to spin this thing over 7, 000 with the juice. The shop said that the springs will work and be fine, but its not his money, it may sound funny but I thought that's why they have spring rates. I could call martin at Tick but he is a busy guy, need so advise guys, thanks
Last edited by M.BOZZ; 10-19-2014 at 11:19 PM.
10-19-2014, 10:35 PM
#4
I have a machine shop working on my heads and making me a cam. I have pac 1237x rated at 750 max lift, now the cam lift is 760 and going to spin this thing over 7, 000 with the juice. The shop said that the springs will work and be fine, but its not his money, it may sound funny but I thought that's why they have spring rates. I could call martin at Tick but he is a busy guy, need so advise guys, thanks
Link
10-20-2014, 07:00 AM
#6
Installed Height is the distance from the top of the spring seat to the bottom of the retainer. Coil Bind is when the coil is completely compressed and cannot physically be compressed any more. The difference between these two measurements should be as much or more than the valve lift plus at least .050" for clearance.
These springs install at 1.80" Installed Height, which is pretty typical of LS heads, and have a Coil Bind height of 1.045". That is only .755" difference. If you attempt to open the valve .760" on that spring, parts will break.
Trending Topics
10-20-2014, 09:55 AM
#9
The installed height of 1.800" is pretty much the standard height. You do not necessarily have to install it at that height.
Your minimum installed spring height is based primarily on valve lift. It's a simple math equation: Coil bind height + 0.050" + Valve lift. In your case, minimum installed height is 1.855"
The question is, what is your seat pressure at 1.855"? You need to measure it to find out. Any machine shop should be able to do that for you.
Your minimum installed spring height is based primarily on valve lift. It's a simple math equation: Coil bind height + 0.050" + Valve lift. In your case, minimum installed height is 1.855"
The question is, what is your seat pressure at 1.855"? You need to measure it to find out. Any machine shop should be able to do that for you.
10-20-2014, 11:53 AM
#11
Yes, you can. BUT, you need to know what the lash is when running WOT and as hot as the engine gets. Heat will change the size of pretty much everything, and at different rates and amounts. You can guestimate, and come pretty close. but you're better off not including it in the calculation. It gives you a good safety margin.
10-21-2014, 08:44 AM
#12
Yes, you can. BUT, you need to know what the lash is when running WOT and as hot as the engine gets. Heat will change the size of pretty much everything, and at different rates and amounts. You can guestimate, and come pretty close. but you're better off not including it in the calculation. It gives you a good safety margin.
The PAC-1237X will be 175@ 1.850" You may want to upgrade to the PAC-1238X.
What is the rest of the combo? Pushrods, valve sizes rockers, ect.
10-21-2014, 10:47 AM
#17
You have hydraulic short travel lifters. You will be fine with the 1237X installed tall or a PAC-1209X.
Are you sure they are not 5452's? Those are solid. I am not sure they make a 5425.
Are you sure they are not 5452's? Those are solid. I am not sure they make a 5425.
Last edited by TurboBuick6; 10-21-2014 at 11:28 AM.
10-21-2014, 11:51 AM
#18
No, solid lifter MOREL 5425http://i1266.photobucket.com/albums/jj528/MBOZZ00/20141021_094358.jpg?t=1413909905 http://i1266.photobucket.com/albums/...g?t=1413909896 http://i1266.photobucket.com/albums/...g?t=1413909905
its not loading pictures for some reason
its not loading pictures for some reason
Last edited by M.BOZZ; 10-21-2014 at 12:04 PM.