Best oil for Yong Heng compressor?

[Airgun-hobbyist]

Just an FYI to this old thread ...

Use 1 pint of oil in these machines to aid in it's splash oiling and longevity. Filling only to the red dot on the sight glass barely allows the needle on the end of the connecting rod to dip into the oil when it is at rest, let alone when running at speed. When that dipping needle breaks off, as one of mine has, you won't be oiling at all and the crank and rod will likely seize if you're only putting in the bare minimum of oil. Adding a pint of oil also keeps the oil cleaner because there's plenty of oiling going on versus oil-less wear.

 

[F6Hawk]

Just an FYI to this old thread ...

Use 1 pint of oil in these machines to aid in it's splash oiling and longevity. Filling only to the red dot on the sight glass barely allows the needle on the end of the connecting rod to dip into the oil when it is at rest, let alone when running at speed. When that dipping needle breaks off, as one of mine has, you won't be oiling at all and the crank and rod will likely seize if you're only putting in the bare minimum of oil. Adding a pint of oil also keeps the oil cleaner because there's plenty of oiling going on versus oil-less wear.

Over-filling oil can cause foaming, and a reduction in cooling. I would agree with filling the sight glass completely, but if a pint is more than that, I'd argue against that.

 

[Airgun-hobbyist]

Over-filling oil can cause foaming, and a reduction in cooling. I would agree with filling the sight glass completely, but if a pint is more than that, I'd argue against that.

So instead of arguing against it, maybe get out your thermometer and a pen and record the temperature after your next filling, then mark the current static oil level, drain it, take off the cover and have a good look that oil level in relation to the crank, do some measuring and mark the rod and dipper length at the bottom of the stroke, refill with a pint of oil and check it against your rod measurement, then run it again to check the heat level. It will likely be a couple degrees cooler because of it getting adequate oil on the bottom of the piston and rings. Then you'll understand what I was explaining to the membership who own these YH compressors and want to keep them in good working order.

I did the research, measured the connecting rod length at the bottom of the stroke and used that to determine the correct fill level. It has many hours on it now, even after breaking off half the dipper, seizing the rod to the crank and subsequently freeing it up.

 

[F6Hawk]

So instead of arguing against it, maybe get out your thermometer and a pen and record the temperature after your next filling, then mark the current static oil level, drain it, take off the cover and have a good look that oil level in relation to the crank, do some measuring and mark the rod and dipper length at the bottom of the stroke, refill with a pint of oil and check it against your rod measurement, then run it again to check the heat level. It will likely be a couple degrees cooler because of it getting adequate oil on the bottom of the piston and rings. Then you'll understand what I was explaining to the membership who own these YH compressors and want to keep them in good working order.

I did the research, measured the connecting rod length at the bottom of the stroke and used that to determine the correct fill level. It has many hours on it now, even after breaking off half the dipper, seizing the rod to the crank and subsequently freeing it up.

Sounds like you are doing a good job of documenting the details. I am just making a generalization with 50 years of experiance behind me, with 35 of those as an engineer.

I don't own one of these (poorly constructed) compressors, just speaking from a POV of mechanical knowledge. More oil is NOT always better.

 

[Airgun-hobbyist]

Sounds like you are doing a good job of documenting the details. I am just making a generalization with 50 years of experiance behind me, with 35 of those as an engineer.

I don't own one of these (poorly constructed) compressors, just speaking from a POV of mechanical knowledge. More oil is NOT always better.

I guess my long winded response was more to the point of 'the oil level at the middle of the sight glass is barely adequate for splash oiling' and more oil is required.

 

[F6Hawk]

I guess my long winded response was more to the point of 'the oil level at the middle of the sight glass is barely adequate for splash oiling' and more oil is required.

Wasn't disagreeing with that, just pointing out what happens to over-filled oil sumps. If your "one pint" amount fills the glass to the top, and not much higher, then all is probably good. If I wasn't willing to drain/fill/measure like you seem to have done, I'd use a full sight glass as the upper limit, as I have many times over the years.

 

[Dog]

I fill to top of red dot as pointed out on attached fill warning sticker. While the manual warns about over and under fills, the choice of oil had me searching for alternates 3 years ago. After 40 years of dealing with hydraulics, keeping my equipment level, when not designed for marine use, is checked. When front cover off for cleaning, it's interesting to see where the dipper is positioned at BDC. Whew, nothing busted yet. Cheers!

 

[dghal]

Well call the thing what you want.
I guess as long as you don't get a nock off

Mine does not run at 35 C it typically runs at at 60C
I fill 45 min scba and a 30 min scba I had to fill from zero when I first got them
It runs like a champ. I have a 7 gallon water container with redline water wetter in it .
I use Moil oil rarus
Top of the red dot in the window.

Mobil-Rarus-400-Series

www.mobil.com

 

[Dog]

Well call the thing what you want.
I guess as long as you don't get a nock off

Mine does not run at 35 C it typically runs at at 60C
I fill 45 min scba and a 30 min scba I had to fill from zero when I first got them
It runs like a champ. I have a 7 gallon water container with redline water wetter in it .
I use Moil oil rarus
Top of the red dot in the window.

Mobil-Rarus-400-Series

www.mobil.com

I like the flash point of the 427, higher than the favorite internet oil Royal Purple another gear pump oil. I'm sticking to ester based non mineral oil as it (seems) to do better, lower temps and smells and used by Bauer and other HP Air dive compressors. The shipping cost of Seco lube is a killer so always looking cheaper. I like redline, seems to work well and all indication better than antifreeze for Alu corrosion. I run on a 30 amp 115 volt circuit and keep a box fan to keep that motor temp down as its a hot running bugger. I found the white motor cap loose so used a dab of RTV to avoid any possible damage, non found. Temps about 50C, indicated, box fan running. So, half than cost of a CX-4 and higher flow rate, me will stick to the YH, to free up hidden funds for next PCP, no?

 

[dghal]

Mine also had the cap just floating in the cabinet

I used a section of inner tube and a long zip tie to secure