May want to check your GX CS2 inspection plug.

JimD

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Mar 27, 2021
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I was checking the grease in my almost new CS2 and took off the head and pulled the inspection plug. I was surprised the inspection plug had a hole about 1/4 inch in it. So the piston area was open. That doesn't seem right so I made a plug out of a washer and a little Epoxy. I also took the grease out of that area and replaced it with some from Target Forge. Letting air in that area can also admit grit and thus premature wear. I wonder if a part got left out or something. The head bolts were also Very tight. I used an old Ryobi impact. I think my pump is OK but I'm glad I caught this early in it's life.
 
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I was checking the grease in my almost new CS2 and took off the head and pulled the inspection plug. I was surprised the inspection plug had a hole about 1/4 inch in it. So the piston area was open. That doesn't seem right so I made a plug out of a washer and a little Epoxy. I also took the grease out of that area and replaced it with some from Target Forge. Letting air in that area can also admit grit and thus premature wear. I wonder if a part got left out or something. The head bolts were also Very tight. I used an old Ryobi impact. I think my pump is OK but I'm glad I caught this early in it's life.
Apologies, but I am not clear as to what parts you referenced.

My the "inspection plug", do you mean the black plastic plug that closes off the piston's wrist pin access hole?

I also don't understand, "The head bolts were also Very tight. I used an old Ryobi impact.". IIRC, the head bolt torque is ~110 inch pounds/ 12 Nm, correct?
 
Yes, the port with the hole is how you remove the wrist pin.

I did not measure the removal force but it was more than I could put on a 5mm Allen wrench. At least three of them were. One was much looser. So I used an impact. I think an impact is less likely to break the bolt. I didn't torque them going back, I just tightened them all I could with a screwdriver. I doubt that's 110 inch lbs. But the dead head test after I got it back together was 15 seconds less.

I added a picture of the as found plug and the underside of it with the washer + Epoxy that is there now.

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20250603_150431.jpg
 
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Yes, the port with the hole is how you remove the wrist pin.

I did not measure the removal force but it was more than I could put on a 5mm Allen wrench. At least three of them were. One was much looser. So I used an impact. I think an impact is less likely to break the bolt. I didn't torque them going back, I just tightened them all I could with a screwdriver. I doubt that's 110 inch lbs. But the dead head test after I got it back together was 15 seconds less.

I added a picture of the as found plug and the underside of it with the washer + Epoxy that is there now.

View attachment 567278

View attachment 567279
Thank-you for the explanations. Good call on the plug repair.
 
My fix is deliberately not permanent. I let the epoxy on the washer set up before I put the washer under the inspection port. The epoxy is to plug the hole in the washer. If I had a circle of plastic the right size I would have just used that. I can remove it if I want or to remove the wrist pin. I didn't and don't think it's appropriate to have the area under the piston open to the atmosphere but one reason I did a dead head test immediately afterwards is I wanted to be sure the pump is working as it did with this area open. The time is, if anything, a few seconds less. So my conclusion is that is best to close off this area unless you are working on the pump. The grease under the plug was also black, not white like it was elsewhere. So it got removed and replaced. I pulled the wrist pin and regreased it but that grease actually looked to be fine.
 
Definitely a breather, it's made that way for a reason. Earlier ones are vented differently

The cylinder venting on the cs2 and cs3 has changed several times over the years as well as the fan directions.

GX has spent many many hours and dollars in R&D on these compressors.

You can even see the black vent in some of the cs3 cases directly in front of that plug in the cylinder.
 
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