Northern Tool Klutch Compressor

As a general rule I've had good luck with Northern Tool and Equipment's stuff over the years. Recently they've added a 12v compressor to their website with some fairly impressive specifications.


150 PSI
5.3 CFM
45A draw

That's pretty impressive when you compare it to the go to EAF compressor, The ARB Dual Compressor.

150 PSI
6.16 CFM
56A draw

Unfortunately I've watched it go from an 8 to 10 day backorder to now a 15 to 29 day backorder. I'm also going to assume it's made in the same Chinese factory that the MV-50, the MV-90, the Smittybilt compressor and the Superflow compressor are. Will it last as long as the ARB? Who knows, but I'm going to take a chance and I'll post up what I find here.
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Code Red

I would be willing to give it a look.

I've got two of the ARB Twins's. Based on my purely anecdotal and non-scientific evaluation, they don't last any longer than the chinese ones.

They are fast when they are new, but they aren't any more durable, and may not be as durable. Mine is still going after about 18 months, but seems to be in the minority. My wife's was rebuilt at about that time, and needs work again three months later. I have a friend with the suitcase style ARB twin who has sent it back for rebuilds three times in two years, and a handful of other friends who say they are getting about 18 months out of them. We're in a club and drive in the dunes 40+ weekends a year, so they get a lot of work. Our compressors are probably doing 8-10 tires every weekend from about 9psi up to 35 or so. Sometimes they do more, sometimes less, but almost never a weekend off. So if you do the math, that's probably 500-600 tires between rebuilds. Ours are both mounted inside the cabin of the vehicle, and are not exposed to road grit or moisture, and they are getting fed filtered, air-conditioned air. Ours are pampered compared to the cheap ones which are usually sitting out in the sun, sand, and dust when they are being operated.

I can't decide if that's good durability or not, but it's clearly not any better than what we see from the Chinese compressors that cost 1/4 as much. I have one of those that I used for two years before I bought the ARB. It's still my backup, and still as fast as when I bought it. I have a friend that won't use anything but the cheap chinese ones. He hooks two of them to his single battery with alligator clips and airs up as fast as we do with our fancy blue ARB's. I've watched him do it every weekend with the same compressors for four years without a hiccup. Lots of other friends with similar Chinese experiences. I love the performance and form factor of the ARB twin, but I am tempted to go a different route for my next one. A little plumbing and wiring and I can have two cheaper ones feeding into a manifold which will take up a little more space, but should give me equal or better performance and better redundancy.
I had a chance today to open up the compressor and give it a test run. First up a shot of the package. The UPS billed weight on this thing was 23lbs, it's quite the brute. I'm not sure what the ARB unit weighs, but this thing is like carrying a small child around.


Once you open the box you're greeted by a styrofoam clam shell that houses a black nylon bag. The pull on the zipper of the bag had already broken off inside the styrofoam, not a good omen. Before anyone asks, no the bag is not of good quality. You could buy a clearance lunch box from the dollar store and get a better quality container than this bag. Oh well, I didn't buy it for the bag.



Inside the bag is obviously the compressor and it's accessories. You get the manual, a hose with a proprietary connection on one end and the inflating tip on the other and three attachments.



Integrated into the hose is a pressure gauge, we'll give this a try in a few minutes and see how accurate it is.


Some specs from the manual. The duty cycle is listed here but I don't recall seeing it on the website.


Time to take it out and try inflating a tire! The clamps that are hard wired onto the compressor are small to say the least. They barely fit over the posts on my Tacoma's battery and on the positive side I had to connect it to one of the bolts on the connector. The wire is an ok gauge I suppose, but moving to some better wiring would probably cut down on some resistance. I may rewire it in the future.


I took a read of the tire pressure using a gauge I knew was accurate after dropping the pressure to about 18psi (33 inch tire). I then connected the compressor and checked the reading on it's gauge. Hmmm...just a little (7 psi) off.



So from 18psi I took the tire back up to 32 psi. This is one of the tires on my M101A2 trailer and this is the pressure I normally run them at. At exactly the 1 minute mark the tire was back to 32psi. Not too bad I guess. The compressor itself wasn't even warm after this 1 minute inflation, although the hose and the fitting it connects to on the compressor were a little warm.

From here I figured I'd break into the compressor a bit and check the build quality. First I removed the small cap holding in the "filter". This is a bit of a joke, but I suppose with some care it'll work to keep things out of the compressor. There's a small foam filter element on top of a small felt ring. What's the felt for? I have no idea. Perhaps they ordered 200,000 of the foam elements that were too short and it's there as a spacer? Not sure.




After pulling the foam filter and the felt pad you can see that the filter housing is just a round plastic clip that is screwed directly into the top of the housing using three small machine screws.


Flipping the housing over reveals that these machine screws were just run right down into the intake side of the housing. Why not create some stand offs or cast a small protrusion that would be tapped to accept these screws? Because this is probably cheaper. If they start to back out or vibrate loose I suppose I'll find a better way to secure them in place.


Here you can see the reed valves for the exhaust (or supply) side of things. These screws are inserted into a tapped opening and the reed valves seem like they're ok quality. If they did fail for some reason the end of an old feeler gauge would probably make a good replacement.


Here are the valves for the intake side of things along with the cheap rubber ring that's sealing the entire thing up.


Here's an overhead of the piston, notice that the heatsink fins only come in contact with the cylinder in 4 places. The MV50's and 90's are designed this same way but I can't help but wonder if a coating of thermal paste to fill in that air gap would help things run cooler?


A couple more shots of the filter housing and screws along with a shot of the compressor next to some pliers for scale.




My initial impression is that this seems to be a notch above the MV50's and MV90's that are out there. I've never seen a tear down of the smittybilt compressor so I'm not sure how this compares. The piston and sleeve in this unit seem (at least visually) to be made of better materials, there's not as much pitting or poor quality metals. The filter elements are a bit of a joke and I may try using something different...cutting some universal lawnmower type filter pads may work.

The hose and it's gauge are a joke but I'm not sure what the thread size is on the proprietary connection to the head of the unit. Once I figure out if it's 1/4 NPT or not I'll see if I can't get some sort of standard quick disconnect in place.

I'm trying to decide if I'm going to mount and hard wire this in somewhere on the truck and if I'm going to add a tank or not. For the next month or so I'm just going to stow it behind my rear seat and use it. I'll keep this thread up to date as I progress.
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Thanks for the detailed write up! I had never heard of thermal paste before so I'm glad I got up today!!!

On a more serious note what would you imagine the wire gauge to the clips are?
Thanks again.
Arctic Silver is what us computer nerds use... never even thought about using it in such an application.
I still have a couple tubes laying around from a computer build a while back. I'm sort of curious to see if it would make a difference but don't really have a way to test it. Good excuse to buy one of those fancy infared/laser thermometers I guess.

Thanks for the detailed write up! I had never heard of thermal paste before so I'm glad I got up today!!!

On a more serious note what would you imagine the wire gauge to the clips are?
Thanks again.
I'll have to measure it tomorrow morning, off the top of my head I'm going to guess 6 awg. That would make sense as it's the bare minimum needed to handle the 45A draw (6 awg is rated for 55A). I could be wrong and it's 4 awg but I don't think so. I'll check in the morning.
Good write up. Thanks for the info. I have never seen a paid reviewer or a magazine actually tear down the compressor and give that level of detail.
Did you happen to get a 1/4 fitting onto this?

I think I may go with a Viair that will mount in the Jeep's engine bay, but you offer an interesting wrinkle in my decision making process.
Did you happen to get a 1/4 fitting onto this?

I think I may go with a Viair that will mount in the Jeep's engine bay, but you offer an interesting wrinkle in my decision making process.
Honestly haven't messed with it again, ended up getting stuck in Texas and California. Kiddo is on spring break this week and I'm off so it's on my list of projects to mess with. Just have to balance it with the honey do list.
No worries. I'm back to work tomorrow. Habersham & Banks have different Spring Breaks again this year. I did get to go to Uwharrie Off-road Training Center for that 4wd-101 class. It was well worth it.

It'll probably be next month before I get an air compressor.
Did you happen to get a 1/4 fitting onto this?

I think I may go with a Viair that will mount in the Jeep's engine bay, but you offer an interesting wrinkle in my decision making process.
Did a little more exploring today inside the compressor and attempted to mate a 1/4 NPT quick connect fitting...

Tore into the head of the unit again and setup a 2x4 clamp to hold everything in place while I unscrewed the tube that connects to the supply port of the head. I believe this tube is the only thing on the entire compressor that was torqued down tight, it was a bit of a bear to take off. Some sort of thread sealing goo was in there and is probably to blame.



Internet: "Those vise grips are the wrong tool for that job!" Yeah, yeah, I know. It's what I have...get over it. Anyway, the threading on this end of the pipe (where the proprietary connector threads in) are much too fine to be 1/4 NPT. There is, however, enough material behind the threading that if you cut the pipe off and then tapped it to 1/4 NPT it should work fine. I believe this is the route I'm going to try.

I went ahead and pulled the tube from the adapter that threads directly into the cylinder head. It also has a fine threading to it and doesn't match up to the 1/4 NPT. So much for this being easy. I called Northern Tool's support line to get a price on ordering another tube (in case I ruin this one) and it's not something they stock. They would have to do a parts request with their vendor in China and it would take months to receive the part they said. Probably easier just to hit up the local machine shop.

After this I decided to look at the electrical side of things. After pulling the two screws still holding the cover on here's what I got:

No fancy circuit design going on here.

There's a no-name 50 amp circuit breaker. There's not really a good thermal replacement that I can source for this so there's no upgrade to be had here.


There's also a no name relay closing the circuit when you flip the switch:

At least it claims it's rated at 60 amps. You could source a Cole Hersee 70A relay to replace this no name for about $6 to improve the overall quality of the circuit, but I'm going to leave it alone for the time being.

The one thing I do find odd is the change in wire gauges inside. The ~10 gauge wire coming in from the positive battery clamp drops to ~12 gauge at the connection between the circuit breaker and the relay. The positive source from the relay to the motor then jumps back to 6 gauge. I have no idea why they'd do this. If this becomes a frequently used item I'll upgrade all the wiring in here and maintain a consistent gauge.


Some of the connections are made using spade type connectors while others are made by soldering wire directly to the tabs on the relay and the switch. I have nothing against solder, but in an application like this where there's certainly going to be vibration it's probably a poor choice vs the physical connector. Solder will eventually become brittle and the frequent vibration could weaken that connection and cause it to break or short. Again if this becomes frequently used I'll upgrade all of this to physical connectors.

At this point I'm torn. I'd like to install this permanently in the Sequoia (so much more room than the Tacoma!) with an air tank and fancy plumbing, but the lack of a 1/4 NPT connection is irritating. I'm going to check with a local machine shop tomorrow to see what they could fabricate that will thread into the cylinder head. I'm picturing a tube style manifold with openings for a pressure relief valve and quick connect fittings.

Or I put it back together in stock form and just haul it around and use it... I'll update the thread with whatever happens.
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Thanks for the continued analysis.
One question: how do you know the wire coming from the battery clamps is 6 gauge? I would guess that it's no more than 12 gauge. Mine doesn't say and I'm thinking of upgrading it so that I can make it longer...
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