Aircompressor Kaput

Groundhog

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My old, tired, used air compressor has almost quit compressing air. So time for a rebuild. Thought a few pictures along the way might be interesting.
The compressor is an Emglo model DU. Rated somewhere around 18 CFM @ 125 psi. It has only been operating at about 1/4 of that since I bought it 4 years ago, so needing a rebuild isn't a surprise. In fact what is a surprise is that I haven't had to do it before now.
My findings: Out of 4 valves in the valve plates 1 is completely gone, 1 was just floating in space and the spring for one is in 3 pieces. 2 piston rings are frozen and collapsed on the pistons, one cylinder has a pretty good score, and the unloader valve is crusty.
All that and it was still working, abet taking longer and longer to fill the tank to 110 psi!
Since I don't really need the entire capacity that this thing is capable of when in tip-top shape I'm going to cut a few corners to save a few bucks. Where I should replace the bad cylinder and a couple of pistons I'm just going to hone the cylinders and re-establish ring clearance with a jewelers file (they don't make oversized pistons). I was planning on replacing the rod bearings and crank bearings but there aren't any rod bearings! No obvious play in the rod big or little ends. And the crank feels good so I'm going to take a chance and just leave the bottom end alone.
A gasket, ring, valve and air filter kit is available for about $220. I can always take it back apart later if I decide to replace something I'm not doing now.
Pics;
0398.jpg 0404.jpg 0405.jpg 0406.jpg 0411.jpg 0413.jpg 0415.jpg 0416.jpg
 
just making the repairs will show a significant increase in CFM's to the tank

i worked in a rental yard for a minute when i was just out of high school.
my boss was a tight wad with the funds to maintain the fleet. he wanted the dollar to go further than it should .

but one thing i got good at was swapping air compressor components from unit to the next.
once a cadaver was made by a customer, i'd quickly dissect the carcass and remove any organs fit for transplant into other victims.
i was amazed how long some brands like emglo could take abuse before they quit

if you can get a cylinder hone of the right size or a speed hone even, you'll be able to whip the cylinders into better shape easily
the rod bearing surface looks good to go.

i wish you the very best of luck
i'm looking forward to see how she turns out :grin:
 
That looks like one solid , heavy duty motor once it's rebuilt,best of luck.
 
@Groundhog,
I definitely support the minimalist approach for a quick rebuild.
I bet you get 90% of the function for 10% of the cost.

That's a nice heavy rig, and looks to be in good hands.

Looking forward to the rest!

eating-popcorn-smiley-emoticon-1.gif
-brino
 
Those old ones rebuild and keep going. I have an old big Kellogg that could be use the same, but do not use it so it just sits.
 
Go for it groundhog just a hone new rings and valves working at 75% will probable last a long long time
Thanks ron
 
Thursdays compressor bumbling . . .

0422.jpg Think I found where some of the missing parts went! Those are steel bits embedded in the aluminum piston.

0423.jpg Part of the ring land smeared over the ring. Ring land is squished in several places compressing the ring. Probably should have bought a new piston or two but the overhaul kit was already on its way by the time I looked this close. I straightened it all out with a jewelers file!

0430.jpg I think in my broke hot rodding days I raced cars with pistons worse than this! This one is ready to go.

1429.jpg Chucked 2 of the pistons up to polish the real bad scratches (high parts anyway) out of the skirts with Scotchbright. Hopefully there won't be enough abrasive transferred to the skirts to hurt anything.

0436.jpg I forgot how much I really hate scraping gaskets. May well be the reason I quit wrenching for a living. It was so bad I drug my little HF compressor from the garage and put up with its .005CFM (ok - maybe it has a little more CFM) running a air grinder with a scotchbright pad.

0433.jpg I knew it probably had a rough life, but how do you break this? Still holds torque on the bolt though.

0440.jpg Jugs need honed yet and it all needs cleaned and flushed one last time, but this much is ready for assembly.
 
Great thread Mike! Keep it coming. :encourage:
 
Nice rebuild Mike.
For low pressure high volume like this compressor was meant for a four cylinder single stage makes sense, why are they so uncommon. Any four cylinder I've seen is a two stage.

Greg
 
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