Valve spring close to coil bind: good or bad for spring life?

[modok]

that's too complex LOL
An entire graph of every position would certainly be a heck of a good spec tho!
As far as I know bind is 100% bind,
but I'm not sure if he spring companies all agree, or if a beehive might want another .010, or 020 because of how they work. SMall enough difference that I don't really need to know, but I do wonder.

[digger]

that's too complex LOL
An entire graph of every position would certainly be a heck of a good spec tho!
As far as I know bind is 100% bind,
but I'm not sure if he spring companies all agree, or if a beehive might want another .010, or 020 because of how they work. SMall enough difference that I don't really need to know, but I do wonder.

in increments of 0.02" or 0.04" would be good enough

[modok]

Good enough for.... who to do what?

[digger]

Good enough for.... who to do what?

Answer the question

[BradH]

Why set them loose? because your lazy?
...

I've been called a lot of things by a variety of people in my life, but lazy isn't one of them.

Over-analytical? Yes.

It would be great if it was both affordable and convenient to put my engine back on the dyno every time I wanted to change something and see the results. It's not, so I try to ask reasonable questions.

[Tuner]

We ran the springs with a little more installed height by .040-.050.
I did not think it would be an issue as there was enough seat and open to get the job done.
The engine broke a few springs after about 20-30 1/4 mile runs but when we changed up the valve train some and
ran them at THE RECOMMENDED INSTALLED HEIGHT as per PAC the issue was solved.
It was a case of using a spring not to its full potential so to speak as far as there installed height went.

It seems to be an isolated issue and have not had the problem any further but when told to decrease the installed height
it seemed funny that they would break with about 20 lbs less seat/open with the extra installed height. But broke a few
down the road. And after going with the min. installed height they have been fine since on both engines.

Just to be clear it was not the same spring number as the OP used it was just a case of stranger things can happen

Spring surge is exacerbated when the frequency of operation synchronizes with the spring natural frequency. Like a guitar string, less installed tension gives a lower frequency. More installed height = less tension = lower frequency = spring surge at lower RPM = spring surge = bad.

https://www.newcombspring.com/resources ... ce-loading

Compression Spring Dynamic Loading Resonance occurs when the frequency of the cyclic loading is near natural spring frequency or a multiple of it.

[modok]

Good enough for.... who to do what?

Answer the question

Fell free to use the door and leave, if that's how it's going to be.
I'm not playing any 20 question game for your amusement.

[CamKing]

Does setting up a valve spring to run close to coil bind (e.g. .060") reduce the lifespan of the spring?

I think it depends on the spring.
I would think you would not want to run to close to coil bind with an H-11 steel, 1.625" diameter spring.
On the other hand, the chrome-silicone springs we had PSI make for the IRL indycar engines ran .030" from coil bind, and were good for 1,100 miles.
Lots of variables to look at.

[68corvette]

I think it really depends on the herzian stress of the wire.
Different materials have different yield stress point.
If spring is not designed to allow low enough stress up to lift untill coilbind, then the service life can be drastically reduced.
If spring is running at its resonance point, then that will add more stress for the spring and running close to coilbind stabilizes the spring and can increase the fatigue life.

But with some springs the maximum recommended lift can be far from coilbind due spring wire material or spring design (coil spacing) and running the spring tighter will reduce the total cycle lifetime of the spring.

Though what I see is that most springs are now days designed to be able to run close to CB, but without knowing the material, diameter, amount of wounds and free length its just a guess work.
Or one can trust the manufacturer.

Giving recommendations to just run it to x distance from coilbind might be a total dicaster in some cases.

[digger]

Good enough for.... who to do what?

Answer the question

Fell free to use the door and leave, if that's how it's going to be.
I'm not playing any 20 question game for your amusement.

You asked to do what? the answer was (it will) " answer the question" (that you pondered) or atleast will shed a lot of light on it

[modok]

Ah thank you. I have done so, that's actually when I started wondering about it about 15 year ago.
As far as the topic of the thread, sorry for over complicating it, but the point I was headed for is that those of us who have been carefully running near to bind as we dare, have not found the limit of how tight is too tight. If being near coil bind is good, (and IMO it almost alway is) then next the logical question is.... what is the low limit?
And...I don't know, all I can say is it's tighter than generally thought.
If the spring company or a peer says you can run .070" from bind on a given spring, that may be a conservative estimate, not a HARD minimum as you might expect. But EVERYTHING has tolerances.
And this is a case where you have a large tolerance stack.

[MadBill]

Hydraulic pump-up and/or pole-vaulting off the top of the lobe could become an issue at near-coil bind installed heights.

[af2]

Here we go again.....
https://www.lunatipower.com/valve-spring-tech

https://www.onedirt.com/tech/engine/ins ... e-springs/

https://www.iskycams.com/installing-a-r ... shaft.html

What I have done and works every time on a 8500+ deal.
+ meaning see's 9500 frequently.

[af2]

Hydraulic pump-up and/or pole-vaulting off the top of the lobe could become an issue at near-coil bind installed heights.

Bill not even going there......... LOL

[digger]

Ah thank you. I have done so, that's actually when I started wondering about it about 15 year ago.
As far as the topic of the thread, sorry for over complicating it, but the point I was headed for is that those of us who have been carefully running near to bind as we dare, have not found the limit of how tight is too tight. If being near coil bind is good, (and IMO it almost alway is) then next the logical question is.... what is the low limit?
And...I don't know, all I can say is it's tighter than generally thought.
If the spring company or a peer says you can run .070" from bind on a given spring, that may be a conservative estimate, not a HARD minimum as you might expect. But EVERYTHING has tolerances.
And this is a case where you have a large tolerance stack.

What interests me is how many cycles a spring can run under controlled conditions ie with no surge. The manufacturers should be able to give a cycle count as they should know the stress at max lift and at installed height to. Then using the S-N curve for the material a life estimate can be established. Running close to bind means running high stress even at idle and the accumulation of fatigue damage will get you eventually. This is probably more an issue on a hot street car that sees alot of controlled cycles and fewer poorly controlled ones.