The Stovebolt Site Forums The Shop Area The Tool Chest Vacume oil changer

--------------------------------------------------------------------------------

Our shop purchased a vacume oil changer,The vacume is created by hooking air up to it and it blow's across an orfice or venturie deal.Well it don't work worth a hoot!I got curious and hooked my vacume guadge to it to see how much it had when full,only 15 inches,not enough I think.The guadge on it just has a needle stating full or empty.The one we used to have worked great,same setup but different brand.Well what I figure is it needs more vacume,So what I'm thinking is drilling out the venturie nozzle a tad bigger to move more air across it,thus creating more flow/vacume?Any opinion's? Has anyone had any experince with one of these?Any thought's would be great,Tom

About 20 years ago I bought a vacuum oil changer and it wasn't worth a "hoot" either. You had to run a small hose down to the oil pan via the dip stick. You could change oil in 6 big rigs before that thing could suck up the old oil. Not only slow but it would make a mess worthy of a divorce.

Try turning the air pressure down on the compressor first, you may be trying to force so much air through that venturi that it isn't working correctly.

Also check for casting flash. I don't think drilling it will do it any good and will probably ruin it. Venturis work on the shape of the chamber just as much as the diameter.

What brand is the vacuum oil changer?
Most venturi vacuum generators are most efficient at 70 psi. Overpressuring the venturi will lead to long vacuum times and decreased vacuum levels.

My company builds vacuum oil changers, mainly for on site maintenance, so feel free to ask any questions you have.

I recommend replacing your drainplug with a quick connect fitting instead of going through the dip stick tube. The dip stick probes are so small in diameter that it takes FOREVER to evacuate oil this way. Again, please ask any question you like and I will answer to the best of my ability.

I'll try the lower pressure first,that sound's like it could be a problem.The deal is I work at a marina,We do oil changes on lot's of boat's,so it's a handy unit when they work right.We had to get this one as the marina went through a complete management change and the old operator took all his tool's when he left.The only thing left behind was an old flyswatter!So we are re-tooling as we need stuff.I'll check the brand tomorrow,and hopefully get some spare time to put my regulator on it and try lower pressures.Thank's for the input! Tom

At work now,tried lower pressure,no-go,Has less vacume at the lower pressure.hooked to 120 lb again and guadge goe's up to previous vacume.same compresser as with the old changer so I don't think that's an issue.Have to use it as is today.It's john dow industries changer,20 gallon.Looking for the manual but haven't located it today,I know it's here!Tom

Found the manual,it say's to use 100-120lbs of air for charging.I'm thinking mabe getting my old airpump from out at my cabin,it's made from an old refrigator pump,it'll pull quite a bit of vacume also.(I know be carefull)!All i'm looking for is to get the guadge to go more than half way up,I'll hook my real vacume guadge to it at the same time to see how much it get's.Also I still have to check for the casting flash in the bugger.Thank's guy's,hopefully I'll get time to check it out more as we are pretty busy with hauling out boat's right now,What a time to find out thing's aren't what they should be!!

If you could get over 20" hg vacuum, it would help. If you are changing cold oil, forget it. The dip stick probes are such a small diameter, you need to have the oil HOT in order for them to perform. Is the tank ASME rated? If so, it will have a large metal tag welded on the tank stating what pressure it is rated for. If it is not an ASME rated tank, be aware that you could collapse the tank with too much vacuum. At this point, I don't see what you have to lose by using your refrigerator pump to create a better vacuum.

I have always wondered how much vacuum is created in a John Dow Industries evacuator. 15"hg is not adequate.

I have a home made vacuum. I used a horizontal tank from an old air compressor. I use an ac vacuum pump to pump the vacuum down on one end and have a ball valve to shut it off. I have a ball valve on the other end and a fitting to put on a hose. We use it mostly to pull fuel out of wrecked trucks with locked fuel tanks, but it will suck oil.

I use a belt driven vacuum pump from a dairy barn to supply vacuum to an old anhydrous ammonia nurse tank (a residential propane tank on wheels). The pump will pull 24" of vacuum when completely deadheaded--I leave a valve cracked to allow some air to flow through to keep the vacuum pump cool. These tanks hold just over 1000 gallons.

I use this set-up to gather used oil for burning in our shop heaters. 18-20" of vacuum in a 2" hose will empty a 55 gallon barrel in about 3 minutes--I have a valve at the end of the suction hose because if the suction hose becomes empty (sucking air only) it will collapse the 55 gallon drum. The small bung will not allow enough air inside the barrel.

To empty the oil from the NH3 tank we put 20 psi of regulated air in the tank and fill the oil heater tanks. We try to bring the tank inside overnight so the oil will be warmed up when it is time to fill the heaters. This system works very good for us.

Thank's guy's,yeah it work's better with hot oil,and oil should be hot when changing anything.But it still dosent preform very well.Hopefully I'll get time to get my pump,busier than hech right now,and a wedding down south this weekend....No not my wedding,still on my first wife,29 years this month!Thank's again!

Got it working much better!I had an idea that the air wasn't moving fast enough...So I took the (muffler) off the fill valve to let the air flow better.And guess what! the guadge goes much higher and pulls oil alet better.Thank's for the help!