Stock 340 springs vs comp 901-16

Killer6 said

Well, the catalog I'm looking at may be considered "vintage" by some now, lol! I believe it's an '03 issue, and One can never rule out errors in the data tables so...........
Here is the chart by line in that issue for all the springs w/the specific specs for the 901's;
Installed Ht.- 1.650"
O.D.- 1.494"
I.D.- 1.080"
Max. Rec. Lift- .400"
Spring Rate- 353#/in.
Part No.- 901
# of Springs- Single
Damper- Yes

Click to expand...

Thanks for all the work to answer the question, K6. Hey I still have my old 70's Ford hop-up manuals and so on, so I place a high value on the old stuff. I have looked at all the online Comp info and the term 'Max. Rec. Lift' (or any variant of that) appears nowhere in the current catalog or in the specialty spring chart that they have onlline. So I don't know what to say about that discrepancy.

Here is a link to the Crane valve spring info:
http://www.cranecams.com/userfiles/file/334-343.pdf

They DO list a 'Max Net Lift' for their springs. I have not looked at every line, but for the ones I did, the 'Max Net Lift' is the difference between the coil bind height and the height for the lowest spring pressure (roughly the valve-on-seat spring height), minus approximately .060". So, in other words, the usable spring height range is all the way to approximately .060" short of coil bind per Crane.

Again, I know of no aspect of valve spring operation that starts to change as the height compresses down close to coil bind. It will make more heat in the spring to compress it more, but how that effects things like weakening probably has to be determined per each spring design. The change in a spring's rate with use is in the material itself, down at the molecular level. I suppose the 901 could use some inferior spring wire...??? (That seems unlikely, but that is just my take.)

OP, have fun in the cold! BRRRRR!