Reassembling YH Compressor - Putting piston back in head procedure.

[USAFANG6799]

I received the parts to replace the entire 1st and 2nd stage head assembly.
Like all things it's easy to disassemble but reassembling is the tricky part.
Is there a video or written procedure that shows how to do this? The top end came with the piston not installed in the head. That means compressing the rings while inserting into the head.
After I take off the front cover where the oil drain plug(crank case) is do I have to replace the gasket or can I reuse the old gasket? I didn't think to order that gasket 

 

[cootertwo]

I'll look for it, but there is a you tube video of a guy that went through his and shows everything. That side gasket was a pain for him, as it had shrunk up a little.
Here ya go....

[USAFANG6799]

Many thanks I'll check them out.
I've heard that gasket can be a PIA.

Is that his REAL NAME

[USAFANG6799]

I noticed he didn't use a sealer on the head gasket. Is this correct?

[USAFANG6799]

So far there's a night and day difference as to how much more air is being put out.
I'm shocked the output had dropped so low. Just one of those really gradual process that happen ya don't even realize it.
Not filling anything now just doing some short runs to wear things in slowly.
Will run it more tomorrow and check for any air leaks.
No water or oil leaks.

One thing I notice is the temperature sensor doesn't fit anymore because the hole is smaller and it's threaded.
Measuring temp with the sensor clamped right above hole on that flat area. Hopefully that's accurate enough for now.

[cosmic]

I don't tighten the cylinder bolt tightly when assembling .. Leave the loose..  I then turn the motor by hand a few times to align the pistons to the cylinders.. Then tighten..  Which I believe the manufacturer doesn't..
I believe this causes many failures..

[USAFANG6799]

I don't tighten the cylinder bolt tightly when assembling .. Leave the loose..  I then turn the motor by hand a few times to align the pistons to the cylinders.. Then tighten..  Which I believe the manufacturer doesn't..
I believe this causes many failures..

GULP........well if there is any misalignment it's too late because it's already put back together and been running.
Guess I will do that next tear down if there was any misalignment.

[cosmic]

You should be good.. I do that since it prolongs the life of the second stage piston seals.. Also ceck for leaks with some soap water.

[cootertwo]

Just a cwazy idea, but I have a Carette, that appears to me, after inspection, that the high pressure piston/sleeve is worn, and it will take 5 minutes or more, just to reach 2000psi, with a plug in the fill hose! Sooooo I have a new Yong Heng high pressure assembly like you just used, and may try to mount it on the Carette, and do a little re-routing of some lines, and maybe wind up with a high pressure piston, that you can replace the rings when they ware. Still thinking out loud, but it sure looks doable. "IF" the crank pin is the same size as the con rod on the Yong Heng rod. We'll see, unless someone else has been down this rabbit hole before.