All Springer/NP/PCP Air Gun Discussion General > "Bob and Lloyds Workshop"
Valve Spring Tension Tipping Point for improved ES
SpiralGroove:
--- Quote from: mubhaur on November 11, 2021, 06:00:35 AM ---I find a lot of people who have in depth knowledge of pcp on this forum.
Valve spring has been previously discussed many times on this forum.
I just want to share my personal experience and want to know the technical causes behind it.
I have RAW HM1000X high power.
I do tinkering myself.
I made some new parts and let the stem of valve open in atmosphere.
This allowed me to decrease the hammer weight from more than 70 gram to 32 grams.
I had to put a lighter hammer spring too.
Now I was achieving the powers of my OEM RAW set up but the extreme spread was too much.
After a lot of trial and error when I installed a very strong valve return spring my extreme spread came into single digit instantly.
So I see the the valve spring tension in regulated pcp has a lot of effect on the consistency of the gun.
I understand that as in the modified set up the valve opens easily, it needs much more strength of valve spring to act in harmony with the new modified parts.
Please discuss this matter.
Regards, Umair Bhaur
--- End quote ---
Mubhaur,
Obviously, there is a tipping point where increased spring tension overcomes the force opening the valve.
Hopefully, Bob Stern or LLoyd Sikes will chime in and give us a way to calculate this phenomena.
Motorhead:
I just made a detailed post about his Poppet spring inquire on his other thread. In a balanced valve, to reduce hang time and initiate a faster poppet closing the poppet spring need to become the STOP of hammers forward progression and give a firm push back to hammer changing the cyclic direction. Yes too stiff a poppet spring and it absorbs TOO MUCH energy from the hammer and lift can be damped as well dwell. Lighter the hammer faster this can occur.
rsterne:
I have heard that anecdotaly a heavier valve spring will lower the ES.... I have never played with it myself....
Bob
JPSAXNC:
I have a non regulated pcp that I put about 5000 pellets through trying to get a tune that I liked. I found that using a stiffer valve return spring flattened the peak of the bell curve, this also required using a stronger hammer spring, to maintain the same dwell time.
rsterne:
Absolutely, a stronger valve spring flattens the curve in an unregulated PCP, allowing a wider range of pressure between fill and refill, and therefore more shots.... The downside is the hammer strike must be increased to get back to the same FPE....
The decrease in ES I have heard reported is in a regulated, benchrest PCP....
Bob
Navigation
[0] Message Index
[#] Next page
Go to full version