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Re: TCV adjustment
Posted: Sun Mar 19, 2023 8:25 pm
by thebuildist
If it were me, it doesn't make any difference if it's forwards or backwards it's still applying pressure to the spring. So I would just make a slight adjustment up or down to make this squeal stop and put it all back together.
But as far as taking it out goes you have to apply a little pressure to it to get it to thread in because the spring is up against it. But there's zero danger of the spring and ball falling out. The ball is on way on the inside of the spring and the spring is about 2 and 1/2 in long.
Bob
Re: TCV adjustment
Posted: Sun Mar 19, 2023 9:58 pm
by MattA
I recall reading in the old forum that adding a flat to one side of the ball bearing will stop it from rotating and squealing. I never tried it but I do have the same problem at times on my 4016.
Re: TCV adjustment
Posted: Sun Mar 19, 2023 10:13 pm
by Eugen
Re: TCV adjustment
Posted: Mon Mar 20, 2023 7:28 am
by thebuildist
MattA wrote: ↑Sun Mar 19, 2023 9:58 pm
I recall reading in the old forum that adding a flat to one side of the ball bearing will stop it from rotating and squealing. I never tried it but I do have the same problem at times on my 4016.
I'd want to have an extra ball bearing on hand, because if the flat gets rotated around where the seal is made then it won't seal. Then, as the "soup nazi said, "No pressure for you!!!" It'll be "all relief, all the time."
Bob
Re: TCV adjustment
Posted: Mon Mar 20, 2023 8:29 am
by DavidBarkey
thebuildist wrote: ↑Mon Mar 20, 2023 7:28 am
MattA wrote: ↑Sun Mar 19, 2023 9:58 pm
I recall reading in the old forum that adding a flat to one side of the ball bearing will stop it from rotating and squealing. I never tried it but I do have the same problem at times on my 4016.
I'd want to have an extra ball bearing on hand, because if the flat gets rotated around where the seal is made then it won't seal. Then, as the "soup nazi said, "No pressure for you!!!" It'll be "all relief, all the time."
Bob
I don't buy the ball rotating , I have heard the stem style squeal .
from research scientists
"The poppet valve is a fundamental component in fluid power systems. Under particular conditions, annoying “squeal” noises may be generated in hydraulic poppet valves. In the present study, the frequency spectrum of the squeal noise is obtained by analyzing the sampling data from the accelerometer mounted on the valve body. It is found that the flow velocity, pressure, and structural parameters have crucial effects on the properties of squeal noise, especially frequency. Larger valve chamber volume or lower backpressure leads to lower fundamental frequency of the squeal noise. An explanation for the squeal noise, as a result of Helmholtz resonance, is suggested and proved by experimental results."
Re: TCV adjustment
Posted: Mon Mar 20, 2023 9:06 am
by RoamingGnome
DavidBarkey wrote: ↑Mon Mar 20, 2023 8:29 am
from research scientists
"The poppet valve is a fundamental component in fluid power systems. Under particular conditions, annoying “squeal” noises may be generated in hydraulic poppet valves. In the present study, the frequency spectrum of the squeal noise is obtained by analyzing the sampling data from the accelerometer mounted on the valve body. It is found that the flow velocity, pressure, and structural parameters have crucial effects on the properties of squeal noise, especially frequency. Larger valve chamber volume or lower backpressure leads to lower fundamental frequency of the squeal noise. An explanation for the squeal noise, as a result of Helmholtz resonance, is suggested and proved by experimental results."
Wow!
@DavidBarkey that's a lot of multi syllable words used in one paragraph... Think I'm going to have to sit down with a
and ask
to stop
for a while so I can
digest your
and interpolate all of your information...
As a mechanic I can confirm that "is suggested and proved by experimental results" actually means - Plug and Pray of existing components hoping that the very audible vocalizations of unseen but obviously present gremlins contained in said component will not be evident after the substitution of an identical component leading to increased operator comfort and decreased calls to the service manager...
Re: TCV adjustment
Posted: Mon Mar 20, 2023 9:12 am
by thebuildist
Re: TCV adjustment
Posted: Mon Mar 20, 2023 9:30 am
by thebuildist
DavidBarkey wrote: ↑Mon Mar 20, 2023 8:29 am
thebuildist wrote: ↑Mon Mar 20, 2023 7:28 am
MattA wrote: ↑Sun Mar 19, 2023 9:58 pm
I recall reading in the old forum that adding a flat to one side of the ball bearing will stop it from rotating and squealing. I never tried it but I do have the same problem at times on my 4016.
I'd want to have an extra ball bearing on hand, because if the flat gets rotated around where the seal is made then it won't seal. Then, as the "soup nazi said, "No pressure for you!!!" It'll be "all relief, all the time."
Bob
I don't buy the ball rotating , I have heard the stem style squeal .
from research scientists
"The poppet valve is a fundamental component in fluid power systems. Under particular conditions, annoying “squeal” noises may be generated in hydraulic poppet valves. In the present study, the frequency spectrum of the squeal noise is obtained by analyzing the sampling data from the accelerometer mounted on the valve body. It is found that the flow velocity, pressure, and structural parameters have crucial effects on the properties of squeal noise, especially frequency. Larger valve chamber volume or lower backpressure leads to lower fundamental frequency of the squeal noise. An explanation for the squeal noise, as a result of Helmholtz resonance, is suggested and proved by experimental results."
In all sincerity, it does seem like if you had some kind of dampener on the ball that it would attenuate the harmonics and silence the squeal.
Maybe take an extra ball bearing, carfully drill it about halfway through with about a 9/64 or maybe 5/32 drillbit, and then silver solder/braze in about a 2" length of 1/8" aircraft cable. Then replace the normal ball with the "ball with a tail", with the tail running up the center cavity of the spring. It seems like that flexible steel "tail" would greatly dampen any squeal noise.
Bob
Re: TCV adjustment
Posted: Mon Mar 20, 2023 9:33 am
by thebuildist
While I'm at it, you know the newer spring design tapers down a lot at it reaches the ball. The old spring design is just a cylinder, with parallel "sides", the new design looks like a funnel, (or a tornado). Same ball size, same cavity size.
I was curious why the newer spring tapers down. Maybe it helps with squeal?
Bob
Re: TCV adjustment
Posted: Mon Mar 20, 2023 9:38 am
by Eugen
