GX CS4

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Ta-Ta Toothie said:
Thought about it, but I'm trying to follow the instructions to a T.
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When I received my CS4, I tore it down a bit. Took the cylinder off the crankcase housing (trying to see where the grease goes, but couldn't really tell), and took the grease pot out. There was a pretty big air gap in there. So I put it back together and screwed in the grease knob 2-3 turns (it spun VERY easily) until I felt a little bit of back pressure, then I backed it off til the previous click. Had I not done this, I would probably have run it for about 15 hours until I was actually pushing grease into the cylinder head. Not good...
 
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F6Hawk said:
When I received my CS4, I tore it down a bit. Took the cylinder off the crankcase housing (trying to see where the grease goes, but couldn't really tell), and took the grease pot out. There was a pretty big air gap in there. So I put it back together and screwed in the grease knob 2-3 turns (it spun VERY easily) until I felt a little bit of back pressure, then I backed it off til the previous click. Had I not done this, I would probably have run it for about 15 hours until I was actually pushing grease into the cylinder head. Not good...
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Doesn't surprise me. I may take a look at the grease pot. Can't hurt.
 
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Grassguy12200 said:
Great compressor so far. I topped off my 30 min bottle and 45 min bottles. I had a slight leak at the high pressure banjo bolt. But it’s all good now. Cylinder head temp stayed at about 115 deg f.
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You didn't mention ambient temp nor run time, but filled a 550 cu in Great White last night and had 152° at the head with ambient of 69-71° after 57 minutes. Pretty cool overall!
 
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It took about 45 min to go from 3000-4500 psi 45 min tank. Room temp was 72deg f. It took about 30 min for the 3pm in tank to go from about 3200-4500. Room temp same ,72deg F. The cylinder head was a constant 115 deg F. All was that was with 3 water bleeds for each tank while filling. My temp sensor is attached to the top of the cylinder head.😀
 
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I wondering what the failure modes of the CS4 are. If it last more than 500 hours before a rebuild that only require o-rings then it would be enough compressor for over 95% of PCP shooters. How many shooters would need to fill a 45 min tank everyday? I'm guessing that the gearbox, crankarm bearing, piston sleeve/bearing will wear out too. Also the motor is probably brushed DC so the brushes will wear out. The power supply may also fail but easy and cheap to replace.

How well did the mechanicals look like inside? Were they clean with adequate lubrication? Are there bearings, or at least bushing where moving parts rotate, or slide, or is it made cheaply to function only as long as the warranty? I've seen some designs where the rotary motor motion is converted to linear motion by just having a offset pin on the crank run inside and slot on the piston rod. That's cheap to do and will fail much sooner than if a bearing were used. Molded plastic gear work for a little while before wearing out, but are cheap. I had a 1988 Corvette that used plastic gears on the camshaft pully lasted many years then the chain jumped some teeth. So it isn't just China that cheaps out to make more profits!
 
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F6Hawk said:
When I received my CS4, I tore it down a bit. Took the cylinder off the crankcase housing (trying to see where the grease goes, but couldn't really tell), and took the grease pot out. There was a pretty big air gap in there. So I put it back together and screwed in the grease knob 2-3 turns (it spun VERY easily) until I felt a little bit of back pressure, then I backed it off til the previous click. Had I not done this, I would probably have run it for about 15 hours until I was actually pushing grease into the cylinder head. Not good...
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I have the same gap with the grease. I'm wondering when it heats up, it does its thing... The diaphragm probably bridges the gap. I'm leaving it as is and will follow the instructions.
 
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Ta-Ta Toothie said:
I have the same gap with the grease. I'm wondering when it heats up, it does its thing... The diaphragm probably bridges the gap. I'm leaving it as is and will follow the instructions.
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I left my rubber diaphragm in. But I made the hole bigger in the middle of it. It seemed to help with the grease going in. I suppose you could make a metal disc to replace it. A guy on here machined some and he said it worked great. The gap in the grease was taken up when I filled ite cup. I smacked the grease cup on the counter top to remove the air. Just my 1/2 cents worth. Grass
 
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Grassguy12200 said:
I left my rubber diaphragm in. But I made the hole bigger in the middle of it. It seemed to help with the grease going in. I suppose you could make a metal disc to replace it. A guy on here machined some and he said it worked great. The gap in the grease was taken up when I filled ite cup. I smacked the grease cup on the counter top to remove the air. Just my 1/2 cents worth. Grass
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There also has to be some suction going on there.
 
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Ta-Ta Toothie said:
There also has to be some suction going on there.
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It pulls the grease in on the down stroke of the piston. But it won’t pull enough as the reason you have to turn the knob every4-6 hrs use. The amount that comes in the grease cpu is small, but it should last for about 25-30 hrs. But I replaced my grease on my GX 4 when I replaced the grease in my Omega Aircharger. Filled both compressors cups.
 
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Grassguy12200 said:
It pulls the grease in on the down stroke of the piston. But it won’t pull enough as the reason you have to turn the knob every4-6 hrs use. The amount that comes in the grease cpu is small, but it should last for about 25-30 hrs. But I replaced my grease on my GX 4 when I replaced the grease in my Omega Aircharger. Filled both compressors cups.
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Kind of, but not really. When you twist the knob (assuming there is no large air gap), you are pushing grease into the little hole, which then allows the piston to draw the grease in. As soon as stasis is reached, no more grease is "pulled" into the cylinder.

Depending on the unit, GX recommends one turn every 6-20 hours. In fact, after the grease pot is emptiy, they claim no more grease is necessary.
 
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New member and new in pcp 1st post
Got a GX4 myself about 35 hours on it now. Reading on them more details on them here had me check mine over again. Had give mine the instructed turns for greasing. Removed pot again and found it had totally emptied itself and know I didn't turn it that enough to do that. Also found the rubber disk had split. Thinking to just to cut another from old inner tube. But is it normal for the pot to empty itself.
 
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Raydee38 said:
It seems like the rubber disk is what limits the amount of grease that makes it to the piston.
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That’s been my experience. Once you remove the rubber disk the compressor will suck whatever grease is in the pot into the compressor. At least that’s how it happened for me.

My solution is to advance the screw until the piston sits flush with the cylinder in the grease pot, back the grease pot screw off 6, 1/4 turns when it needs grease and then fill the empty space flush with grease. That way it gets the correct amount of grease at the correct time.
 
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Probably going to replace my disk with a piece of inner tube, remember when new it had only a tiny pinhole in the center. So hoping to replicate it. But will be keeping a lot closer eye on it now. Mostly use for direct filling gun. But did get an o-ring kit for it, GX website just put them back up in stock a week or 2 back. Better to have it than need when they're out of stock.
 
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Sawney Bean said:
That’s been my experience. Once you remove the rubber disk the compressor will suck whatever grease is in the pot into the compressor. At least that’s how it happened for me.

My solution is to advance the screw until the piston sits flush with the cylinder in the grease pot, back the grease pot screw off 6, 1/4 turns when it needs grease and then fill the empty space flush with grease. That way it gets the correct amount of grease at the correct time.
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Cannot see how totally blowing off the instructions from GX will benefit you in any way, but it's your compressor, so...
 
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F6Hawk said:
Cannot see how totally blowing off the instructions from GX will benefit you in any way, but it's your compressor, so...
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Introducing the exact amount of recommended grease at the recommended interval is blowing off the instructions? But you go ahead and trust a floating baffle that has been extensively written about as being a flaw in the design.
 
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