Vacuum pump/ for oil changes

[clint]

This may be kind of OT, however it could also cross over to be useful in the machine world. I have one of those small hand held vacuum pumps for removing fluids from things, like power steering fluid, coolant in automobile type applications for the most part. I want to build one with a electric motor, some different size fitting/hose fittings, and it will be used a lot if it turns out that it works for changing oil, coolant, etc as a maintenance item. I have no idea where to start, what type of motor would I need for this, HP, also type of pump as it will need to be self priming I'm sure. I have a Little Giant magnetic drive ($800 job), however it is not self priming, and is way to big for this application.

I also know they sell them however I need a project, and would like to scrounge this one if I can. I have a Lathe, no mill, I'm thinking of making the adapter/fittings myself for different pipe/hose sizes, I will need to put together the motor, and pump from purchased or scrounged items. I'm thinking ebay, surplus etc, but need some helpful suggestions on what to start looking for.

Clint

[doctor demo]

I am a little confused, You say ''self priming'' . Are You talking about a self priming fluid pump, or a vacuum pump ? If You are refering to a vacuum pump You will want a trap to keep fluid out of the pump.

Steve

[MPHJUNKIE]

Both of my neighbors have boats that I do maintenance on and that includes changing oil. I use to use a little hand held pump but never liked it so last year I made my own. I used an old pneumatic automotive air conditioner vacuum pump and made a catch can for the oil. It doesn't take much air to run and because it acts like a syphon all I do is stick the tube into the dipstick holder, plug it in and walk away.
$27 for the pump.
$2 in fittings and hoses.
Being able to sit back and watch it do the work instead of me being all cramped up like I'm playing twister by myself on top of a boat motor in the hot sun...priceless.

[JCHannum]

A vacuum pump is nothing more than an air compressor with connections reversed. Since vacuum is nothing, you can't pump it, you are pumping the air out.

A small, cheap compressor head can be reconnected or modified to a pipe thread on the inlet. One of the most common vacuum pumps is the Gast, it is a rotary vane pump that is either an air motor, air compressor or vacuum pump depending on connections and whether it is driven or it drives something. The plain motors and pumps show up on eBay regularly, usually pretty cheap. They need no priming.

A 1750 RPM motor will suffice for drive. HP requirements will be pretty low, 1/3HP will be plenty for your purposes depending on the pump size. You definitely do want to connect a drop out between the pump and the oil pan to collect the oil and keep it out of the pump.

[hitandmissman]

vacumm pump/for oil change

Being retired from industrial maint. and working with and on autos all my life I do not recommend using vacumm pumps. It is the same as the 10 minute oil changes you see. It will change the fluids but leaves the sludge in the bottom which is what you want to get out of there in the first place.

[MPHJUNKIE]

I agree it may not be as complete as using the drain plug but that means lifting the motor or drilling a hole in the boat. It's the only thing I use it for and it's better then the hand pump.

[jdunmyer]

I use a little ShurFlo air-powered diaphragm pump to change oil in my VW Jetta. No crawling under, removing the bellypan, etc. Works great!

I pump the oil into a gallon jug to be sure that I got it all, am using a stiff plastic tube down the dipstick tube, with a TyWrap on it so I know it's at the correct depth. There's a regulator on the air supply, and I am careful to not crank it up too high, I ruined one pump by getting impatient. :-(

[jcarter]

I have a 12 volt waste oil pump made specifically for marine engines. Since I got the "oil sucker" in the attached photo the 12 volt unit has become obsolete. At the risk of starting a whole new "discussion" I don't agree with the comment that a vacuum pump will leave sludge. This may be true in an industrial environment but I have not seen any evidence to support that in a marine/automotive application. I have worked in the marine industry since 1985 and have done literally thousands of oil changes with a vacuum pump. Maybe in an engine that has been neglected or not run up to full operating temperature prior to changing the oil. If the sludge is that sticky that a vacuum pump won't pick it up I doubt it would flow out the drain hole in the pan. I have seen more sludge up in valve covers than in oil pans.

[bollie7]

what about an auto air con compressor as a vacuum pump?

bollie7

[lunkenheimer]

Compressor type pumps don't like liquids

If you get a decent flow of liquid into a compressor pump it'll see a hydraulic lock and break up. The other vacuum pump mentioned is a venturi style (I believe) and definitely not a piston pump. Some diaphragm pumps handle liquids ok.

Actually, sucking too much oil into an air conditioner compressor (known as 'slugging') will break it, even if you are only intending to pump freon and not oil.

I don't have a lot to contribute on the original question except to say that fresh oil with some sludge is better than old oil with more sludge, and that a nice warm engine will suspend more sludge than one that has been sitting for a week or a month, though fresh oil with no sludge is best.

[bollie7]

Forgot to mention in my previous post. I meant the aircon compressor with a catch can for the oil.

bollie7

[PatTheRat]

I've pumped oil and water, antifreeze etc. out of this pump for 30 years. Still works like new...

http://www.jamestowndistributors.com/userportal/show_product.do?pid=4146&BASE

[derekm]

... I have a 12 volt waste oil pump made specifically for marine engines. Since I got the "oil sucker" in the attached photo the 12 volt unit has become obsolete. At the risk of starting a whole new "discussion" I don't agree with the comment that a vacuum pump will leave sludge. This may be true in an industrial environment but I have not seen any evidence to support that in a marine/automotive application. I have worked in the marine industry since 1985 and have done literally thousands of oil changes with a vacuum pump. Maybe in an engine that has been neglected or not run up to full operating temperature prior to changing the oil. If the sludge is that sticky that a vacuum pump won't pick it up I doubt it would flow out the drain hole in the pan. I have seen more sludge up in valve covers than in oil pans.

This is where both are right and wrong.

The issue is the pickup/outlet placement and the ability to remove the sludge components. The trouble with a lot removal of oil by suction, is poor pickup placement with sump design so that it doesnt remove the last fractions and pickup tube or pump suction volume capacity that is unable remove the last sludge/air mixture.

That said I've seen some gravity drains leave a lot to be desired.

A well designed and placed pickup and sump coupled to a a high enough volume suction is the equal to gravity drain.
If possible I would suggest a permanent suction pipe attached to the sump e.g. replace sump plug with pipe routed to a convienent point to attach vacuum.

[figge]

I live up in the swedish mountains and run a small repair shop with
focus on snowmobiles.

I have built this "pump" to drain out thick oil trough small holes in
snowmobile chain cases.

It involves a pneumatic piston that manouvers an hydraulic one,
and a ball check valve system for the oil flow that i made in my lathe.







It creates a vacuum so heavy it makes a blue spot on my finger if
i put it on the end of the suction pipe, its great for sucking "dirty" oil trough
long thin hoses

__Figge__

[rwf71]

A guy I used to do a lot of work for (passed away) ran a septic service, as in pumping out septic tanks , porta potties, etc. He had an old ford truck with a large tank on it for "pumping out" & collecting the contents of septic tanks and such. The vacuum pump for this rig (which worked very well & made him pretty good money for MANY years) was nothing more than a hose running from the intake manifold of the trucks engine to the airtight collection tank on the back with a ballvalve. To "suck" the contents into the tank all he did was submerge the pickup hose from the tank into the "prouduct" to be collected & an open the ballvalve while the truck's engine was at idle.
Would make about 17 inches of vacuum (put a vacuum gage on your car or truck while idling & see for yourself). When first opening the ballvalve he would just "crack it" for a while so the truck's engine didn't stumble to badly untill the vacuum in the tank reached 14-17 inches, (had a gage on the tank to monitor this) then open the valve fully & let er suck. Worked like a charm, just make sure the volume of your collection tank is greater than the tank being vacuumed, cause you don't want that CRAP in your engine. Rick