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old DeVilbiss air compressor

T

TWISTED0880

Plastic
Joined
Jun 28, 2019
new member but have been frequent on the forums as a reader so i picked up a old devilbiss 330 air compressor its in pretty good shape i cleaned it up painted it but when i drained the tank there was a lot of oil in it as well as most of the lines i checked all the valves popped the head off the cylinder walls look fine no pits or scratches my guess is piston rings only i cant find or dont now how to find the ones i would need for this specific model so im calling out to all the experts out there i hope this is the right section
 
Could be that someone lugged it on its side, maybe even stored it that way for awhile and crankcase oil went thru valves. Was crankcase full of oil or low. I'd top off crankcase, run it for a month, and keep eye on crankcase oil level, if its losing oil it needs a ring job. I found rings for an old Devilbiss a few years ago, forget Co name, had to tear it down and get ring dimensions first.
 
it wasnt just oil it was yellow slime i did change the oil and it seems to be going through it plus it takes a bit to fill up
 
the original owner took pretty good care of it minus this problem so he kept the oil level up i spoke to him and he said he kept an eye on the oil and filled it regularly which makes me think it was going through it more than normal the crank case was full from what i understand when you get the yellow slime its when oil is compressed with moisture or something along those lines it wasnt just straight oil if it was i would have figured exactly what you were suggesting
 
Probably mousse which is a mix of oil and water. Oil fog into a wet tank forms the mousse which flows to the bottom of the tank.
It will plug automatic drain valves until it is washed out. Maybe alcohol to thin it? Can you remove the inspection port to wash it out.
Bil lD.
 
How big is tank? How much slime came out, a quart, a gallon, 5 gallons, more? I'd still be inclined to run it and observe oil consumption myself, I don't put a whole lot of faith in what previous owners say. But hey, its your compressor, go for it, pull pistons, pull rings, measure bore and ring thickness and width, parts house can match your dimensions. Of course if going that far you will need rod bearings if it has them, and main roller bearings too.
 
Use oil that's formulated for air compressors. I read an article once about a compressor tank at a car wash that exploded killing a worker. An investigation into the accident found that the oil used in the pump created an explosive gas in the tank.
I know in the past I have used engine oil in pumps.
Since reading the article I use compressor specific oil. I never considered compressing and vaporizing oil from the pump into the tank. That's what makes diesel engine ignition. Its not worth risking your life.
They may have used recycled oil with a volatile mix.
Be safe
 
how much slime ? if i had to gauge it less than a gallon its an 80 gallon compressor and i did clean it all out put fresh oil in it and the oil level has diminished rapidly i only ran it a couple times since the rebuild and thx for all the quick responses
 
Its pretty rare for a workshop compressor to have worn rings......Ive seen them sitting out in dusty yards never serviced,still didnt have worn rings......If the unit is splash oiled,the oil level may be too high......high /excessive oil will defeat brand new rings and piston..............as to slime.....drive a truck,you will see gallons of grey slime drain from airtanks every few hours running.
 
this is a vintage compressor i think around the 50s but if the rings are not bad what else would cause all that oil the previous owner definitely could have over filled the compressor but i put fresh oil right to the mark on the dipstick and a lot seems to be gone after a couple of cycles as well as it seems to take a while to fill but i could be totally wrong about everything but i love to hear everyone's suggestions im just hoping someone with experience with this model might be able to shed an opinion
 
The dipstick may be wrong too.,if it has a splasher attached to a rod bolt,it may be wrong too.There may also be a shield from inside the crankcase missing.Anyway ,lifting the barrel isnt a big deal,and checking the rings,piston and cylinder
 
John, I may be wrong, but pretty sure that compressor uses ring oilers, and I don't recall any splash shields. But wrong dipstick could be a problem!

OP, ring oilers are steel rings that ride on either side of crank, inside crankcase, to bring oil up to crank. Pretty sure max rpm on that compressor is 900, if its turning faster that may explain oil consumption, as rings will be spinning too fast and slinging oil.

What is motor RPM? Motor pulley diameter? Compressor pulley diameter?
 
IMG_0935.jpgIMG_0940.jpg



IMG_0941.jpg

i believe it runs at 800 rpm i used a synthetic blend for oil dont know what was previously used and i think it has rings

IMG_0937.jpg



sorry not the greatest picturesIMG_0936.jpg
 
Why did you paint the tank before running the unit and checking that everything worked?

Anyway, at least you are using SMC regulator and filter. You definitely have blow by of crankcase oil.
When I rebuilt a motorcycle engine there was a catalog with different size rings and pistons. I would take off the pump and replace the rings and re-hone the cylinder walls. If you are lucky that is all it will take.
 
it works and worst case i replace the pump. it was during the dismantling for paint that i discovered the oil
 
i guess you need a little more back story i purchased it off craigslist the guy had it running for me it functioned it was cheap enough that if it didnt work i could replace the pump but id prefer to make this one run the way it should
 
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