Spring rate and max RPM

[LiquidX]

Just looking to see what the max RPM I can safely attain with these springs I'm using. I'm not exactly a mathematician.

Pressure
066 @ 1.580"
175 @ 1.210"
237 @ 1.000"

Rate
294 Lbs/in

These are being used on Delta Cam HKS grind 272 cams

 

[bastarddsm]

Just looking to see what the max RPM I can safely attain with these springs I'm using. I'm not exactly a mathematician.

Pressure
066 @ 1.580"
175 @ 1.210"
237 @ 1.000"

Rate
294 Lbs/in

These are being used on Delta Cam HKS grind 272 cams

How the #### are they 294lb/in, when you say they are 237 when compressed and inch. Which are they? 237? 294?

F=MA is all you need to figure out how high you can rev them to. You'll just have to figure out the relavent details.

All you have to do is determine the ramp rates of the cam. From there you can calculate what is the maximum angular velocity the cam can have, and not have the ramp rate exceed the acceleration the valve/spring/retainer/keepers/rockerarm can acheive. Don't forget to account for the friction of the guide and the seal, or the fact that the weight imposed on the system by the spring and rocker arm is not static. It changes with the displacement of the system.

Once you get the max angular velocity, I'd divide that by 2 for a nice saftey margin, and then convert it into crankshaft rpm.





For $100 I'll calculate it. That actually pretty cheap as I'll have about 2-3hrs in it, and engineering consultation is not cheap.

 

[LiquidX]

Haha, I actually just copied it directly from Manley's PDF cataloge 22125 is the spring part number.

http://www.manleyperformance.com/dl/2011/cylinder_head_components.pdf
Page 19

 

[bastarddsm]

Oh, those are seat pressures at different installed heights.

 

[LiquidX]

I'm not exactly a head guy that knows numbers, rates, formulas, etc. Do you mind elaborating or even letting me know the max RPM I'd be able to safely run before floating a valve? I wouldn't mind seeing the formula in work on the post.

All-in-all, I'm just really trying to make a decision if these springs are what I'm going to be needing or will even work well for me and I just need the above information to make that decision.

 

[brian9397gsx]

The numbers you posted are installed height, stock is 1.580 then you add shims to get the other heights and seat pressures. I know that doesnt answer your question just hope it clarifies the numbers you wrote.

Im curious also as Ive just received my manleys and will be running on gsc s2 cams.

 

[hubz91talontsi]

I am also because i just ordered my manleys yesterday, and ill be running kelford 272's.

 

[LiquidX]

I've taken them to 8500 fine but so far the only issue I've had was a shattered spring seat.

 

[bastarddsm]

I'll need to know the weigh of the valves, springs, reatiners, keepers your using. I'll need to figure out a mass distribution for the rocker. Oh and the lift of your cam every degree or so.

I can tell ya right now, your probably not going to like the results. I'm gonna guess its gonna be stupid low, like 5krpm, without doubleing it for saftey.

 

[LiquidX]

HAHA. Well for one I don't know the weights. Two, these are much stiffer than stock springs which have a safe red line of 7500. Perhaps I'll just go email a company and see what they say.