Breaking the ends off of valve springs,

So, Manley springs, 520# on the seat, 9000 RPM, Brad 6 heads.

The ends of the springs are breaking off. All of them. Talking the last 1/8" to 1/4" of spring at the end of the coil is breaking off.

WHY.

It's been doing this for a year. As the springs soften up, they get moved to the exhaust then garbage can. They pressures stay good, but fishing the ends of the springs out is old news.

Any input?

 

I have ran Manley Nextek springs, PSI springs and PAC springs. The PAC springs seem to be the worst for breaking off the tips. Anybody got a spring that will hold pressure- (480+ on the seat) and not break? Dave Germain

 

Yes Dave,..get those .100 taller intake valves from Bob, and put them in that tractor,.. and then call
Brandon Johnson for some Ti Xtreme springs,..600 PLUS on the seat, 25 plus
runs later and still at that number,.. change them out at 450 closed psi.

 

i thought the PAC springs were better than the manley, as said they do break but not so much and to be honnest it makes no difference to the spring (as long as the tail dont end up in the oil pump) then it will fuck your springs and everything else

 

It has a lot to do with the resonance & frequency of the spring. If the RPM you are mostly operating at is causing spring surge then you may need a higher frequency spring.. The "fuss point " of the spring may need to be lowered or made higher in the RPM to get the harmonics out of the operating RPM of the engine

 

Does running closer to coil bind reduce the effects of spring flutter or surge, just something I have heard about wondering if there was any truth to it.

 

I've heard you want to run as close to bind as possible. I think someone from PAK told me this. Maybe Richard. I'm not sure.

 

Our head guys tell us to be within about 50 thousands of the springs advertised "max lift" numbers to avoid spring surge.

After some out of control runs (aka lots of RPM), I've broke tails off also. But not in normal conditions.

 

The thin ends (tails?) of the springs break off because they get hot and brittle when the manufacture grinds the spring flat.
To fix the problem - cut them off before you install the springs.
It really is that simple.
The spring manufactures should do this but it is labor intensive and raises the cost of the part.
The little things in engine blueprinting are the steps that prevent problems later.
Oh by the way the further away from coil bind you are the longer the springs will last.

 

Can't agree with 776. A spring can go in a harmonic state @ 6000 rpm & be fine @ 6500. Springs have different frequency ranges & the best way to find which is suited is via a sprinton machine. Lets not forget that the "tails" are ground flat & the better springs are already cut off slightly, yet they will break off more if things aren't right. The right fitting retainers & locaters are underestimated for the springs usage, even the way the spring is handled. They should not be touching in the box or knocked around as stress rises will occur & that will be were it breaks first. Some of the latest springs should not be handled & come with gloves.What is this telling you? Tooo many people underestimate the poor old spring & the work it does.Be kind to it.

 

I wonder what kind of care titanium springs need and if they are coated to prevent damage since crack propagation can be accelerated by things like methanol and brakleen in unprotected titanium.

Richard Gavle

 

I wonder the same... My guess, not so much.

EDB