Lubrication for Yong Heng rebuild?

Forums Air Tanks, Pumps, & Compressors Lubrication for Yong Heng rebuild?

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    FlexWagtail
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    Member

    Piston, rod, rings, etc. kit has arrived from China for YH attempted rebuild.   Any advice on pre-assembly lubrication would be appreciated.  Have lith grease, moly paste, etc.  not sure what to use or what’s necessary.  Got plenty of hydraulic oil for crankcase.  It’s the upper I’m thinking about.  (Photo is broken part being replaced for reference).  Thanks

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    Centercut
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    I’d use synthetic Air Compressor oil vice hydraulic oil. As far as the upper (high pressure) piston, rings and cylinder, use NO LUBE at all on that section. Just clean it well, ensure it is lint free and assemble dry. The lower (low pressure) piston, rings and cylinder just a very light coat of the air compressor oil. Better to have LESS than MORE on these HPACs…
    ​Mike

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    prfssrlee
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    +1 on Mike’s advice. The rings will wear in so you will want to take off the second stage housing after maybe thirty minutes of run time and clean off the carbon buildup. Then probably again after another thirty minutes. 

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    FlexWagtail
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    update:  BIG FAIL   
    The piston rod on my Yong Heng seized.  There is a dipper on the rod that mysteriously broke, thus depriving the crankpin of oil.  I ordered a new piston assembly from Ali Express for only $20 BUT……    The new assembly second stage piston did not fit in the Yong Heng.  The new part had 4 plastic rings, and the original had three.  They looked identical in diameter, but in fact the new second stage piston was a few thousands too large.   “Okaaaaaay…..” sez me.  “We’re not done yet.”   I took apart the new assembly and moved the new rod to my old original piston set to replace the original rod that seized.   This time the reassembly went smoothly.   But after about a 3 minute run under no load to wear in the new rod I got a catastrophic failure.   The failure point was where the first stage and second stage pistons are connected.  I tried hard, but I’m done with Yong Heng.  Even if yours runs great for a while, it will need a rebuild.  I could not find a reliable source of correct parts.  Without that, you’re screwed at some point down the road. 
     

    Did I make a big mistake? I bought a Yong Heng compressor from China!!


     

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