Is my compressor bad???

S

Steves69LS3

  • Need help diagnosing compressor
    I have an eaton 3 stage 7.5hp pump Its about 3 yrs old. Properly maintained The other day while i was using it my transfer pipe burst at the fitting Now this is a big pump and motor sitting on a 60 gal tank meant for a smaller set up. But as i upgraded i put a bigger baseplate to accomodate Transfer pipe consists of a sharkbite steelbraided 3/4" hose connected to a sharkbite 90 degree fitting to 3/4" copper pipe into tank relief valve Now this setup worked flawless for years Lately i noticed a little bit of oil seeping out of fill plug. Emailed eaton and they said to check valve to see if it releases head pressure after shutting down It does. Switch and valve are working correctly I put new transfer hose and firtings on and decided to run pump with the oil fill cap off Please take a look at the video and any input is greatly appreciated P.s Eaton does not make this pump anymore and a new one is $450
    frown.gif

 
steve i think your fine. you have to remember when that piston comes to the down stroke and its heading toward the crankcase that all that displaced air has to go somewhere. that is the whole purpose of that vent. my vent on my eaton has a plastic standpipe of sorts that sticks up to keep oil from blowing all out and it does BUT over time there is always going to be enough oil mist made to accumulate a little over hours of use. the front of my pump by the plastic vent pipe is always a little wet. not enough to drip all over but you can see its a wet around that area. i have 2 diesel generators and even both of those would blow a rag around like that if i held it in over the crankcase vent.
 
Thanks jim thats what i figured. Eaton is trying to sell me a new pump lol an inline 5hp they say is an upgrade.
Thank you for reassuring me :)
 
Keep an eye on the outlet tube that goes into the tank. My Eaton would pump some of that oil into the copper tube and inside of the line would be oily. That is when it's getting to much blowby past the rings. It would be a good check to see if the rings are blowing by each direction. Neither of my 4 quincy's will pump visible oil into the tank. My Eaton sure would.

I know I'm bitter and you guys have heard my Eaton story but I'd throw that pump in the dump and get a real pump. Something about 30-70 years old with good parts availabilty and rebuild it.
 
steve i just pulled my vent tube and stuck a rag over it. same deal as you. thats totally normal which i what i thought. your moving air around so you have to vent the crankcase psi.

lucky for me i have never had any of the issues you had brad. i think mine is coming up on 10 years old and i use the crap out of it 7 days a week. no oil in the tank or air. atleast no more than any other compressor i have ever used. i have taken the crankcase cover off the side as well to clean out any metal powder that settles out of the oil and there is really very little. maybe i just got lucky....or you unlucky. could be my pump is of a different model as yours also. maybe they has issues with certain pump designs. who knows.
 
I also ran the pump before i connected the new transfer tube and the air was clean no oil mist. I think its because of the hot weather and being run all day caused the fitting to blow. Plus its the first summer that i had it outside in its own little shed. It does get hotter in there than when it was in the garage. I always prop the door open when its in use. I want to put vent grills on the sides to let more air in.
Would it help more if i drilled a small hole in the cap? Or is there a better vent cap out there that i can replace mine with?
 
well i have the oil fill cap then another vent with the standpipe vent fitting. its just a black plastic screw in tube with a glass marble inside to work as a check valve. that is right at the front of the compressor pump. do you have that? thats all i ever needed. just allows the crankcase to vent while keeping the splashing oil from coming out.
 
I do not have that
To be honest i dont even think my cap is vented lol
You can see it briefly in this video

 
Many multi-cylinder pumps have little net change in crankcase volume while running, since one piston is going up while the other is coming down, so a vent is not really necessary. I don't know if that's true about that 3-cylinder Eaton pump, though.

The best way to tell if you have too much wear on the pump is if it starts taking a long time to fill the tank with air. Of course, this requires remembering how well it did when it was new. Next time I change my pump, I'm going to write on the tank how long it took to fill to what PSI when new.
 
crash- that's a great tip- logging new vs worn 0 to whatever psi AND writing it on tank so ya can't lose it lol.
 
Ahh i do remember
It took my old pump 14 minites to fill 60 gal tank
Eaton took 6
I will try that tomorrow
 
Also im wondering if the rubber o ring is at fault. Its not so rubbery anymore
 
thats a totally different pump than whats on mine. mine seems much larger. its their 7.5hp that has the 10hp pump. here is mine. you can see the vent pipe sticking up in the center

DSCN5169.jpg
 
beautiful pump Jim
im going to start out by putting a new o-ring on it ans see if its the same otherwise where can i get a vent tube?

thank you everyone
 
i actually busted mine off and just got a new one right from eaton. it was a very inexpensive part from what i remember. $5-8 or something like that

yeah crash that looks like it. i know it was a copy of one of the big comp mfg brands but forgot what it was. i just looked up the 707. looks like a current pump. they have probably made that thing for years. man that is expensive too. 3 grand for pump only.
 
Last edited:
Went to see how long it took to fill the tank from empty
4:31

Im thinking i am worrying too much and there is no problem at all

Thank you everyone
 
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