regulator fitting issues

[JerryD]

Did you drill the bleed hole in the cylinder between the two O rings?





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[yorkieRM]

Yup bleed hole drilled as per instructions.

Like I say it holds air so not made any mistakes there.

But you charge the gun, it fires a few shots as it exhuasts the small stand off reservoir then nothing. As if there is no air in the gun, yet the pressure gauge reads just under100 bar on the rifle.

No air can be heard escaping from any seal.

Correct me if I am wrong but should the regulator allow a flow of air at its set pressure to fill the small stand off reservoir, so you fire with a more constant metered amount, then when the pressure falls below that of the reg it should fire till the cylinder is exhausted.

[DavyG]

The reg is pre-set to 100 bar. You say the gun still shows around 100 bar but nothing happens. There's your answer! The reg won't allow any more air into the firing chamber. The reg won't open to allow more air in unless the pressure on the pre-reg side is greater than 100 bar. The gun will not fire until it is empty. The reg is working as it should....you just need to charge your gun.

[Captain Bongo]

The reg is pre-set to 100 bar. You say the gun still shows around 100 bar but nothing happens. There's your answer! The reg won't allow any more air into the firing chamber. The reg won't open to allow more air in unless the pressure on the pre-reg side is greater than 100 bar. The gun will not fire until it is empty.

Once the main reservior pressure drops below the regulated pressure (as compared to atmospheric pressure at the vent when working properly) the Rob Lane reg still fills the reg chamber but obviously only to the pressure of the main reservior. You can fire the gun until empty.

[radiofan]

The fact that the pressure gauge reads around 100 bar means that there is pressure in the reg chamber. This is backed up by the fact that you drain the gun by loosening the pressure gauge. The pressure gauge is behind the regulator, measuring the regulated pressure.

I think your valve/hammer adjustment is such that it will not fire if the pressure is too high. You can try a few things:

1) Take the regulator out, put a standard cylinder on it, charge the gun (without reg) to 110 bar and see if it fires OK.
2) Unscrew the valve spring a few turns. This is probably what's holding the valve closed.
3) Increase the hammer spring strength.
4) Lower the regulator pressure to the point you know it does fire.

You say you've put the gun together from bits, possibly it is just not adjusted right.

[yorkieRM]

Before fitting the regulator the gun worked well. Only had it running around 10ft lb but it had no problems firing till trying to fit the reg.

Today I did as suggested and unscrewed a few turns and hey presto it has started to work. Charge gun, reg stand off cylinder charges to just over 100 bar and it'll fire till the whole cylinder is exhausted. Have found a few more issues but working those kinks out.

I do have a small persistent leak which I only discovered this morning when going back to the gun it had drained overnight. Turns out its leaking out of the bleed hole. Spoke to Mr lane and his advice is to hone the cylinder as any small scratch will allow air to leak past the sealing rings. So far spent 3 hours with small cylinder hone and can still see some small scratches so will crack on with it tomorrow and post my results when I have finished.

Also my valve isn't in the greatest condition. So thinking about making a new one...can anyone suggest the best plastic for this seal. PTFE or polyurethane?

[boko]

glad your on the home run

[daystatedan]

Great news .Keep us updated.

[radiofan]

I do have a small persistent leak which I only discovered this morning when going back to the gun it had drained overnight. Turns out its leaking out of the bleed hole. Spoke to Mr lane and his advice is to hone the cylinder as any small scratch will allow air to leak past the sealing rings. So far spent 3 hours with small cylinder hone and can still see some small scratches so will crack on with it tomorrow and post my results when I have finished.

This is the hardest part of fitting a regulator. I found that you need to be quite bold in the approach to cylinder honing.
The dowel method of using 500 grit wet'n'dry in an electric drill at high speed worked best for me. Don't be shy otherwise it will take ages to get it to seal.

[yorkieRM]

OK guys...so after taking the advice from here, speaking to rob lane himself and watching the you tube videos...here's the latest...

Cylinder honed out using a combination of the dowel method with wet and dry of varying grades, and self adjusting honing tool I use for springers. Got near in a mirror finish inside it now, so with some slightly bigger or rings and a little bit of PTFE tape the slow leak is now all but non existant. System has held around 200 bar since yesterday afternoon which is good enough for me.

So no problems then...

Not quite...

I am using a standoff supplied with the regulator. Approx 20 mm long. My standoff cylinder holds around 100bar. Gun shooting fine. Chrono'd for safety and initially running high so a few more turns on the valve body got me down to under 11 ft lbs using air arms field diablo.

The only issue I seem to have now is if I leave the gun for say 20 minutes pressure gauge goes up to about 140 bar and my first shot is much higher velocity than the next run of shots as the reg drops back to about 100bar.

This also happens as the pressure in the main cylinder drops, so the reg seems to increase in pressure and my velocities go up.

My thoughts to what could be causing this are(and corretcy me if wrong)...tight fitting regulator piston not allowing prompt regulator function...

Or

Slight damage to the knife edge of the piston which is allowing a slight leak into the reg stand off cylinder till more pressure is built and a better seal is made.

Any further ideas/advice gents?

[wonky donky]

OK guys...so after taking the advice from here, speaking to rob lane himself and watching the you tube videos...here's the latest...

a little bit of PTFE tape the slow leak is now all but non existant. No it should be non existent.

So no problems then...Yes if it leaks slightly

Not quite...


The only issue I seem to have now is if I leave the gun for say 20 minutes pressure gauge goes up to about 140 bar and my first shot is much higher velocity than the next run of shots as the reg drops back to about 100bar.

This also happens as the pressure in the main cylinder drops, so the reg seems to increase in pressure and my velocities go up.

My thoughts to what could be causing this are(and corretcy me if wrong)...tight fitting regulator piston not allowing prompt regulator function. Well maybe if it feeds too slowly which would be unuaual

Or

Slight damage to the knife edge of the piston which is allowing a slight leak into the reg stand off cylinder till more pressure is built and a better seal is made. Probable if everything else is as it should be? & most likely!

Any further ideas/advice gents?

Bit worrythe first part, where's the PTFE tape?

rifle is obviously leaking air to the chamber, if it was leaking down the outer wall of the cylinder you would also lose main cylinder pressure. If it was leaking past the first piston seals that would also vent so you either have a slow fill or a leaky shut off which may well cause an eventual power drop if left overnight, if it didn't should still increase in chamber pressure.

[stryder5]

Before fitting the regulator the gun worked well. Only had it running around 10ft lb but it had no problems firing till trying to fit the reg.

Today I did as suggested and unscrewed a few turns and hey presto it has started to work. Charge gun, reg stand off cylinder charges to just over 100 bar and it'll fire till the whole cylinder is exhausted. Have found a few more issues but working those kinks out.

I do have a small persistent leak which I only discovered this morning when going back to the gun it had drained overnight. Turns out its leaking out of the bleed hole. Spoke to Mr lane and his advice is to hone the cylinder as any small scratch will allow air to leak past the sealing rings. So far spent 3 hours with small cylinder hone and can still see some small scratches so will crack on with it tomorrow and post my results when I have finished.

Also my valve isn't in the greatest condition. So thinking about making a new one...can anyone suggest the best plastic for this seal. PTFE or polyurethane?

The valve head should be made from PEEK polymer.

[mark112]

The valve head should be made from PEEK polymer.

Or just buy one! They are about £8 from bgaltd. The same part no as the 4 and 5 series (Part no S370). Lot less hassle than making one

[yorkieRM]

Originally air was quite literally pouring out of the bleed hole. Now, when the charged cylinder is put into a bucket of water a tiny bubble forms over the bleed hole and sits there so I think that's just residule air leaving the hole.

The PTFE tape is wrapped round the grooves of the reg body and is one of the leak curing suggestions on the you tube video made by rob lane...how to cure slow persistent leaks.

I was concerned the PTFE may have migrated and caused the slow reg action. I am feeling yet another strip down to try and sharpen the knife edge and flatten the reg seal and see if that works.



As for my valve seal, as all I had in the workshop was PTFE rod I have made a new valve with that and its performing really we'll. I have put a very slight taper section onto it and its spot on. Will take a pic of it if I strip it out again and post it up here.

Another thought I had is to drill out the transfer port, I think this will mean a more efficient transfer of air... Meaning I can tighten up the valve spring and reduce the hammer spring preload...hence more shots from a full charge...so has anyone drilled their transfer port on a S410...and what would be the best diameter to drill it to?

Cheers for all you guys advice.

Yorkierm

[radiofan]

The only issue I seem to have now is if I leave the gun for say 20 minutes pressure gauge goes up to about 140 bar and my first shot is much higher velocity than the next run of shots as the reg drops back to about 100bar.

This also happens as the pressure in the main cylinder drops, so the reg seems to increase in pressure and my velocities go up.

My thoughts to what could be causing this are(and corretcy me if wrong)...tight fitting regulator piston not allowing prompt regulator function...

Or

Slight damage to the knife edge of the piston which is allowing a slight leak into the reg stand off cylinder till more pressure is built and a better seal is made.

Any further ideas/advice gents?

I had the same problem, only less severe. The knife edge is not sealing properly. You will need to re-face the seal and maybe sharpen/finish the knife edge. My pressure rises from 95 bar to 110 bar after a few days. I just fire a shot off before I start to use the gun proper.

Another thing you might want to look out for is that the FPE increases slightly at maximum fill of cylinder (190 bar). This is because more air will rush through from the main cylinder through the reg to the valve upon firing. This can be tamed somewhat by reducing the size of the reg charging hole, by sleeving around the narrow part of the reg body or by putting something into the threaded hole down the middle.