Impact PP valve housing 2.0

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weatherby

weatherby

Member
Jun 5, 2015
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--, Belgium
Decided to make a new valve housing for my Impact X with power plenum. 

The original PP valve housing seats the valve quite deep, which could probably decrease flow. The bore is 10.6mm,and the valve OD is 7.5mm. Because it is basically in a tube, this limits the flow.

In the old design, this isn't the case, so I decided to make a new valve housing by using the old valve with longer valve stem, and move the valve seat up quite a bit to maximize the use of the 3 slots in the valve housing.

I also increased the valve hole to 7mm, and ground a 7mm drill with a radius to make the end of the hole rounded as well, all to improve flow.

Replaced the original Delrin valve poppet with a 8mm PEEK poppet as well to match with the bigger valve hole.

The slots in the housing are 10mm, and I've milled them in a way that the lower slot is in line with the manometer hole to add a additional plenum, just in case.

Did a small test, but the hammer struggles to open the 8mm valve. I will have to make a custom hammer spring with 1.5mm wire to overcome this issue.

More to come, will keep you posted. 



1583190686_15009487955e5d929e475348.16154524_IMG_20200302_151539.jpg

 
Nice work. If you make that whole valve stem assembly out of some titanium it would net you a 40% decrease in weight.
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You know, the whole valve assembly of a FX Impact IS already completely made out of titanium ;)

It is very light already.
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On my gen 3 only the rod and hammer seat are titanium. The other parts are stainless, I believe 303. Even though it has very little magnetic attraction you can still see it by passing the parts close to a strong magnet hanging from a string.

I had similar ideas about the valve housing but the slots don't need to be there. You do want the valve to be as far back as possible for best airflow but make the housing without slots and set your boring bar to thin the walls between the two center o-rings. A 1mm wall thickness would be plenty then drill a 3mm hole in the wall for the manometer. This configuration will give you less shrouding around the valve for better airflow while maintaining plenty of strength.
 
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@heavy-impact The valve I have used for my new valve housing is a first or second gen, and it is completely made of titanium.

My gen 3 and PP valves, same story. 

You can't test it properly with a magnet, even non-magnetic materials interfere with magnetic flux.

Regarding the valve, I agree that further back is better, but it is only about 3mm's, and my valve hole is 7mm all the way through. So basically, in a 30cal, the whole TP path is 7mm in my altered design.

There are more ways to increase flow, but with the slots milled in, it is easier to check the position and surface of the valve seat and you also can see what you are machining.

By the way, wall thickness of the O-ring grooves is already only 1mm, that is the limiting factor why I couldn't change the PP valve housing, I would have cut into the o-ring grooves, causing a leak. 

Ideas are the simple part, realizing them is a lot harder. I don't have CNC you know ;) 
 
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By the way, wall thickness of the O-ring grooves is already only 1mm, that is the limiting factor why I couldn't change the PP valve housing, I would have cut into the o-ring grooves, causing a leak. 
Ideas are the simple part, realizing them is a lot harder. I don't have CNC you know ;)
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That's why I didn't say drill it. You would only step the boring bar over between the two center o-rings creating a jug. If you have a DRO you can just watch the numbers, no need to see the surface while turning. There are lots of tricks in machining.
 
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By the way, wall thickness of the O-ring grooves is already only 1mm, that is the limiting factor why I couldn't change the PP valve housing, I would have cut into the o-ring grooves, causing a leak. 
Ideas are the simple part, realizing them is a lot harder. I don't have CNC you know ;)
Click to expand...

That's why I didn't say drill it. You would only step the boring bar over between the two center o-rings creating a jug. If you have a DRO you can just watch the numbers, no need to see the surface while turning. There are lots of tricks in machining.
Click to expand...

I was talking about the horizontal transfer port, not the valve housing. 

Hogging out the internals is easy, but how do you think to cut the valve seat 5cm inside the body?

On top of that, one of the o-rings would still be in the way to get a big transition between valve, valve seat and horizontal TP.

I moved one of the o-rings 1mm further back to gain extra space to cut the valve seat. There is nothing more to gain, because the vertical TP is in the way.

When I would have made it like you said, the valve would still have been sitting in a "small tunnel" with restricted flow. 
 
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I was talking about the horizontal transfer port, not the valve housing. 

Hogging out the internals is easy, but how do you think to cut the valve seat 5cm inside the body?

On top of that, one of the o-rings would still be in the way to get a big transition between valve, valve seat and horizontal TP.

I moved one of the o-rings 1mm further back to gain extra space to cut the valve seat. There is nothing more to gain, because the vertical TP is in the way.

When I would have made it like you said, the valve would still have been sitting in a "small tunnel" with restricted flow.
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I see your point but the areas represented by the green square in this pic could be removed if the slots were left out, stopping short enough from the seat to maintain proper strength. There may be room for a chamfer leading to the seat if the seat were moved forward a bit. I understand your points I'm just sharing ideas. The most important thing is to have fun.

I made my own valve rod assembly in titanium and the coupler just above the valve seal on mine if far lighter than the original. The dimensions are the same is why I said my original can not be titanium.

1583272260_19567863605e5ed144d6afd6.85037178_sample1 -.jpg

 
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