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After the last thread i decided to purchase the LSM on head spring tester which btw is a very nice tool! Since my buddys engine is on the stand in my garage i started testing his valve springs (which are actually my old springs). He's also running my old cam and i want to say Chris Straub said that he wanted to see #160 on the seat. Running through the springs I'm seeing most springs are around #160 but i see a couple that are showing #140-150.

I know the instructions for the tool say to calibrate it with a bench spring tester but i don't have one so I'm trying to get the tool as close to aligned up as possible. My main goal here is to just test the springs against each other to see if they are all relatively close.

My main question is, when is a spring considered bad?
 

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After the last thread i decided to purchase the LSM on head spring tester which btw is a very nice tool! Since my buddys engine is on the stand in my garage i started testing his valve springs (which are actually my old springs). He's also running my old cam and i want to say Chris Straub said that he wanted to see #160 on the seat. Running through the springs I'm seeing most springs are around #160 but i see a couple that are showing #140-150.

I know the instructions for the tool say to calibrate it with a bench spring tester but i don't have one so I'm trying to get the tool as close to aligned up as possible. My main goal here is to just test the springs against each other to see if they are all relatively close.

My main question is, when is a spring considered bad?
LSM'sstuff is nice stuff. I really like my lash adjusting tool with the built I torque wrench.
It isn't always a matter of BAD, more like the same. I would definitely think about shiming the 140 spring(s), and as long as you at it, shim the 150 to bring them up to 160 as well. After that, if the same springs fall behind the others, they go. Never shim a spring twice.



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It depends on the quality of the springs but usually in serious competition 5% is would be considered to much of a spring rate variance, street performance 10%, that would raise question with your spring that has 20lbs difference. If you didn't know the rate before it could just be that manufacturer's QC. Find the lift of the cam at the valve and install your spring in the measuring device at installed height subtract the lift and see what you have left before solid height. Depending on the spring for clearance you should have a minimun of .010 to .015 per active coil, an active coil is one that is not touching another coil at the ends where they are ground flat, it can be a number like 5.25 or 6.5 x .010 or .015 this will tell you what the design of the spring needs as clearance. After this you can shim the seat to any number with out binding and if you can't the spring has failed.​
regards
 
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