valve spring damage - solid height

[racerdude5]

Has anyone ever broke a stock 318 valve spring? I compressed one to solid height to calculate the max lift for that particular spring. Since then I've assembled the heads. The mopar performance book says to never use any spring which has been compressed to solid height in an engine. Dad says it will be fine though, should I take the heads apart and replace the spring?

 

[yellow rose]

How long did you leave it compressed? One time to stack won't hurt it.



Edit: I always check for coil bind with the retainer on, unless it's a single spring.

 

[famous bob]

How long did you leave it compressed? One time to stack won't hurt it.



Edit: I always check for coil bind with the retainer on, unless it's a single spring.

a friend that does flow bench work, and race heads does it on every head he builds-----no problem !

 

[brian6pac]

You have to hit coil bind so you know what it is. I just put them in a vise with 2 retainers and slowly compress and measure it.

 

[racerdude5]

How long did you leave it compressed? One time to stack won't hurt it.



Edit: I always check for coil bind with the retainer on, unless it's a single spring.

I don't remember exactly but I'm almost certain I only compressed it fully, long enough to measure it with a vernier caliper. I think I did it twice to double check. Thanks to all of you guys for the responses.

 

[dirty white boy]

well,..what was your max lift/coil bind measurements??? enquiringly minds need to know...lol

 

[brian6pac]

Also if you use a pressure gauge the pressure rises fairly steady then it jumps way up before the coil actually binds.

 

[racerdude5]

well,..what was your max lift/coil bind measurements??? enquiringly minds need to know...lol

It's been a over a week now but I'm pretty sure that at an open height of 1.233", there was .020" clearance between all the coils. According to the Haynes book I've referenced you need at least .010" between coils. So the stock 318 springs should be good for .454" lift, maybe even a little more. But I wouldn't push it. The installed height I referenced was 1.687". Note that I didn't use a spring tester.