HW100 plenum fill time

[bambuino]

Hello --

First overhaul of my HW100SK. [ link ]

I can hear the plenum filling in my HW100, and can say the word "mississippi" in the time it takes to lock. Seems kinda long, but then never paid much attention in past 5 years.

When fitting the valve stem through the Teflon guide, seemed pretty tight. Will that smooth out? Hasten plenum fill, with break-in?

TIA, Mark

 

[GrahamHenderson]

the exhaust valve has nothing to do with the plenum filling.
the Teflon valve stem seal needs to be tight or air will blow by it when the valve is opened

 

[bambuino]

My bad...better I said..."when fitting part number 2655aK thru part number 2655d, seemed pretty tight..."

Is the slow plenum fill time a symptom of something I overlooked, or could improve with some extra work?

 

[GrahamHenderson]

like I said it needs to be tight
it is not tight around the valve stem when the hammer strikes the valve ... it may feel tight to you when assembling
... when you fully assemble the front block (no air)you can push the valve open with the hand held hammer tip

 

[bambuino]

For a second there thought I was in wrong place.

 

[GrahamHenderson]

Re slow filling of plenum ...

assemble the front valve and check that the new O ring is not nipping onto the piston prod



...

 

[bambuino]

like I said it needs to be tight
it is not tight around the valve stem when the hammer strikes the valve ... it may feel tight to you when assembling
... when you fully assemble the front block (no air)you can push the valve open with the hand held hammer tip
View attachment 1018711

When I filled for a timed leak check I tapped the valve stem couple times to make sure seated well. I did have to polish the crown, as there were concentric tooling marks I didn't like. Held pressure over couple days.

Anyways...

Could it be slow action due to improper lubrication of Bellevilles? Maybe they are "sticky"?

 

[bambuino]

Re slow filling of plenum ...

assemble the front valve and check that the new O ring is not nipping onto the piston prod


View attachment 1018715
...

Thanks! I test fit those repeatedly and can say with confidence the piston rod rides smooth in the main valve exhaust, over the bearing and spring. Doesn't mean I won't tear it open again soon if need.

This is an easy gun to work on I am finding out.

 

[Wing Commander]

Could it be slow action due to improper lubrication of Bellevilles? Maybe they are "sticky"?

I had one apart recently and after rebuilding it, the elderly Bellvilles were distinctly "moody" and didn't want to play anymore.
They were replaced for new ones, and ..... what a transformation. The reg pressure was easier to set and the refresh time was virtually instant.

 

[bambuino]

Well, I can report an improvement on this matter. Plenum fills with snap, rather than like wheezing old man. Maybe things settled in during the chrono testing.

Pressure holding steady.

Trying to find my Cole-Parmer digital gauges from back in day mixing diving gases. Make me a proper reg tester gauge.

 

[Robbo]

When one of the small o rings gets squashed beyond all recognition on the valve stem the refill gets sluggish. Replace it and it should fill quicker than you can cock it.

 

[Blackmax]

When one of the small o rings gets squashed beyond all recognition on the valve stem the refill gets sluggish. Replace it and it should fill quicker than you can cock it.

Nothing to do with the valve stem, it’s to do with the inlet/regulator valve inner and outer being done up too tight as @GrahamHenderson referred to earlier in the thread.

The exhaust valve O ring is PTFE and forms under pressure, it should be a tight fit or it’ll leak during the firing cycle.

 

[Robbo]

Can't remember the name or exact location, but it was small and didn't even resemble an o ring. I replaced every single o ring and that one was the only damaged looking one of the lot, so naturally assumed that was the problem. If you do a full strip and replace and come across a mushed black blob that's the one I'm on about, was about 7 years ago still going strong.

 

[Mr Fettler]

I fitted a gauge to my HW, fired off about 10 shots, it took 10-11 seconds for the air to settle, Huma reg was the same, Lane just slightly quicker, hence the old trick of using a single shot loader. I chrono'd mine using a magazine firing off as quick as possible and it was all over the place.

 

[bambuino]

Thank you all for your kind advices.

@sea level, finish rebuild 18 july
854.8 fps, ES 5 fps. Two pair dups.

@3000ft elev, 23 July
854.4 fps, ES 10 fps. No dups

So, although I mentioned plenum fill is somewhat snappier, still seems loud. I say loud because prior to my opening the rifle up, I had never heard the reg in action. Seriously, never a peep. Thats my baseline.

Before anything I think attending to a further repolish and lube of the Bellevilles is in order. I had used a thin film of light machine oil on them to prevent corrosion. Not enough maybe? Perhaps molybdenum grease a bit thicker? Pls advise on appropriate type and amount of lube for Bellevilles, I might have messed that up.

 

[Blackmax]

I fitted a gauge to my HW, fired off about 10 shots, it took 10-11 seconds for the air to settle, Huma reg was the same, Lane just slightly quicker, hence the old trick of using a single shot loader. I chrono'd mine using a magazine firing off as quick as possible and it was all over the place.

It should be instantaneous, it could have been your gauge.

 

[Blackmax]

Thank you all for your kind advices.

@sea level, finish rebuild 18 july
854.8 fps, ES 5 fps. Two pair dups.

@3000ft elev, 23 July
854.4 fps, ES 10 fps. No dups

So, although I mentioned plenum fill is somewhat snappier, still seems loud. I say loud because prior to my opening the rifle up, I had never heard the reg in action. Seriously, never a peep. Thats my baseline.

Before anything I think attending to a further repolish and lube of the Bellevilles is in order. I had used a thin film of light machine oil on them to prevent corrosion. Not enough maybe? Perhaps molybdenum grease a bit thicker? Pls advise on appropriate type and amount of lube for Bellevilles, I might have messed that up.

Don’t use moly on the Belleville washers, a smear of light oil is fine, I use synthetic oil.

 

[Mr Fettler]

It should be instantaneous, it could have been your gauge.

Brand new, calibrated by Mr Lane as the label on the box said
I will take a look at how to connect it to my bottle to test it, 1/4 male to 1/8 female. Will see what best fitting have
Thank you for the heads up