Help Me Choose An Air Compressor
 

I want to do a leak down test soon and I'm beginning to hear suspension creaking so I will be acquiring air tools soon.

Again, the playing field is Craigslist, here are the contenders.





Another one, but this one is modern.


https://norfolk.craigslist.org/tls/6192059827.html


Probably my 1st choice


https://fredericksburg.craigslist.org/tls/6184971484.html

What do you guys think?

The older craftsman if still in good shape is to me a much better compressor. The newer one puts out just half as much air and could even be a diaphragm type. The newer 3.5 horse rating is also a joke compare to the older motor.

Interesting. Well I don't mind unplugging the oven if need be. It looks like a beast.

Leak down test uses very little air and under 20psi to do the test. Pick a small and modern one unless you are a professional mechanic. That is my experience, everyone has different preferences.

What about suspension work?

The $99 pancake compressor from Home Depot has served me well. Noisy little turd but pretty good otherwise

The only time you need a big air compressor is doing paint spraying, professional garage, tire shops or you think you are a professional that you cannot do without one. All suspension work can be done by hand or a 3 gallons compressor. At the end of the day, it is your money and decision.

I'd buy the amrox, as you wanted 110v power. My advice would be to buy a compressor that allows you to change the oil. My experience is that they run much quieter.

I've R&R'd both the front and rear suspension on my 190 with nothing more than an electric impact gun and hand tools, no need for air. Even the impact gun was a luxury. Leakdown test is another story, but a tiny compressor should be sufficient for that.

For 220, you would need a pair of adjacent slots on your panel, as the 220V feed is two phase. You can have an electrician wire a 220v socket, and it would probably cost three times the price of the compressor. While it's not hard to DIY, you can run afoul of local building codes (not to mention electrocute yourself). As for using your oven socket, maybe, if the plugs match. But how long is the cord on the compressor? If it doesn't reach, a two phase extension cord is not a cheap item.

Many points of view and understandable. There has been a generation that has known and lived with these limited smaller air compressors. I guess it is just a case of what you want to do both presently and in the future.


As for a test on a used compressor. The most important one is the time to fill the empty tank from empty. If it is rated at say nine cubic feed per minute output. It should fill the 20 gallon tank in just a little more than two minutes till shut down.

Thanks for the info



I can only they're oil filled, however both are belt driven so they'll be much quieter than the direct drive compressors.


It isn't long at all on the 220v one, I never thought about that.


I'll think about this for a bit. Thanks everyone.

Take a look at the link below for our air compressors; happy to answer any questions that you may have!

Portable Air Tank - PelicanParts.com

The two phase part of the above post isn't accurate. House power in the US is "split phase " though it is generally called "single phase".

The easiest way to visualize 1, 2 or 3 phase power, think of a 1 , 2 or 3 cylinder engine.

With obsolete two phase power, the second phase sine wave is offset by 90 * ( quarter of a wave ) . The circuit was generally fed with 4 wires and motors had 2 separate windings to consume the power. https://en.wikipedia.org/wiki/Two-phase_electric_power

With single " split " phase house power, sine waves are 180 * offset ( half of a wave ) . These systems have 3 wires but only use 2 depending on if 110 or 220 voltage is needed. No matter the voltage, everything remains consuming single phase. Motors have one winding that is used for run. ( There is sometimes a start winding that drops out after the motor is turning but that is beyond the conversation here. )

https://www.google.com/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=0ahUKEwiXzuCKivjUAhXGyj4KHanNCPwQjBwIB A&url=http%3A%2F%2Fwww.globalspec.com%2FImageRepository%2FLearnMore%2F20122%2F240120SinglePhaseWavef ormTransparente0e210f2a73b4e2aa95274447e1b5892.gif&psig=AFQjCNHtmjLOfLLyT6KVjHAbdiLmzvDx9g&ust=14995 47921437169

With single phase house power, one can get 110 by selecting a hot and a neutral. To get the other "phase " of 110 you select the other hot and same neutral. To get 220 you select both hots.

Three phase power is used for generation and distribution to your neighborhood. It is also used directly by industry. With 3 phase power, the sine waves are offset by 120* ( third of a wave ). This is very efficient because the power transmission is smoother and motors less expensive / more reliable. Motors have 3 windings.

I don't know the current rate , but don't see an electrician charging more than a few hundred $ to install a 220 system if the wire / outlet can be fastened to the wall. For a short run materials would be sub $ 50 and take an hour.

Installing a 220 V outlet differs only slightly from a 110 v outlet. The actual wire is the same, the breaker needs to be a 2 pole ( we are using both hots ) and the third terminal is a safety ground not a part to pickup 110 V. If the device like a clothes dryer needs 110 to run the motor and 220 to run the heater, 4 wires must be used ( 2 hots , one neutral and a safety ground )

At higher voltages, a smaller wire diameter can be used Vs running the same load at a lower voltage. A three hp single phase motor running at 220 V will consume 13 amps , A 14 wire gauge extension will work though the thicker 12 gauge is better. ( for house wiring, 14 G is good to 15 amps and 12 G to 20 )

The oven socket will be rated for 50 amps so the plug won't work directly. You could make a jumper cord to a 220 V 15 A socket but in theory the cord should have it's own breaker. Breakers are rated for expected load and wire size. If a compressor that consumes 13 A locks up and the load goes higher, the breaker won't trip the the compressor will become a heater element.

As for a compressor, the 2nd one is overrated and there is no way it is 3 HP, $ 120 is kind of high for what it is. Craftsman 3 1/2 HP Air Compressor. 125 psi, 25 gallon tank, 8.5 cu. ft/min @ 40 psi. $120

Most real compressors have the cubic foot rating at 90 PSI not 40. Rating the compressor at 40 gives the appearance the compressor is "bigger" As for the HP rating, the numbers on consumer units have been inflated for years ( same goes with lawnmower ratings, that is why they have gone to Ft / Lb torque )

The third compressor does not have a belt guard and is Taiwan / China made, I'd pass.

For leak down a small carry 110 compressor is fine and might even be able to deal with intermittent impact tool use. A 2 or 3 HP _oil_ lubricated piston compressor would be better for impact use.