Sanden On-Board Air Compressor in a '77 2F FJ40 (1 Viewer)

[subzali]

I haven't seen any writeups on MUD about using a Sanden compressor for on-board air, so I thought I would post this one up. I have this build documented on the Rising Sun board originally here:
Brahma On-Board Air

I've never liked going to the gas station to pay for compressed air to fill up my tires after a run. I also don't like inconveniencing others by asking for their air/CO2. I don't like the small 12V compressors because they're noisy, don't have high CFM, don't have a great duty cycle, and the better ones are pretty expensive. And you have to store them someplace when you're not using them.

I don't like CO2 because you have to continually get the bottle filled (repeated expenditure of $$), it takes up a lot of space, and you could forget about topping it off before a trip and run out after filling only 1/2 of your tires. It's not an "endless" supply.

I don't like Yorks because the typical York mount makes you move the alternator down to where the smog pump bracket is. I don't like the idea that my alternator could be submerged in a water crossing while my air compressor, which is not a necessary accessory, is happily dry at the top of the engine bay. I also wanted to try something different that I had heard about from former TLCA President Red Fox (who is also a local club member of mine) as well as from a couple others.

Hence, the Sanden compressor. Found as an A/C compressor in some Fords, Volvos and possibly other vehicles, it has a slightly lower CFM as compared to Yorks, is tubular in shape which saves space, and the only "drawback" is that you have to add oil because it's designed to be lubricated by refrigerant like an Aisin compressor. But there's a port on the top that allows you to do that, so it just becomes part of pm.

The Sanden SD-510 is what I'm starting with, just because that happened to be what Neil Quigley gave me. The SD-508 I think is more commonly found in junkyards and is reputable for this service. The SD508 is a 5 piston compressor which can supposedly put out 9 cfm and 300 psi. I think the SD510 might do slightly more cfm. It's also a 5-piston compressor. The SD-508 has 8 cu. in. displacement, and the SD-510 has 10 cu. in. displacement. I did a quick calc and at 800 rpm the SD-510 should put out about 4.6 cfm with no backpressure. At 2000 rpm it should put out about 11.6 cfm with no backpressure.

Here are some links to websites that reference the Sanden compressor, one of which came from rusty_tlc on MUD:
Grungles Homepage
On-Board-Air Using a Sanden Compressor - Jeepaholics Anonymous

This is the mockup I did when I was in the middle of my power steering conversion. Since I am not running a smog pump, I used the smog pump bracket and tensioner as the foundation of my installation. The tensioner needs to be bent slightly to align with the mounting ears on the Sanden compressor, and the mounting bracket needs no modifications at all.

Now, the smog pump bracket is designed to fit 8mm bolts. The Sanden pump is designed to mount using 10mm bolts. So I went to McMaster-Carr and ordered a few sleeve bearings to make up the difference:

The mounting ears on the Sanden also don't exactly line up with the ears on the smog pump bracket, but a simple spacer from Ace Hardware (3/8" ID, 3/4" OD, 3/8" thick) will make up the difference:

Here's before/after shots of the sleeve bearings going into the mounting ears:

When the compressor is mounted, it's a little close to the stock exhaust manifold, but some heat shields should be able to fix that no problem.

This picture shows the wrap of the belt around the OBA compressor pulley. I have a JT Outfitters bracket holding my Saginaw power steering pump, and I'm using a pulley off of a Volvo 240, due to the wide belt it can accommodate like stock Toyota. This picture still has my old pulley with narrow belt shown.

This picture shows the front mounting bolt on the bottom. It's an M8x35 I believe, and it was just a hair too long so I added a second washer at the head end of the bolt to bring it back away from the pulley just a touch:

This picture shows the rear mounting bolt on the bottom. It's an M8x40 I believe, with the 3/8" long spacer to make up the distance between the ears on the compressor and the ears on the smog pump bracket:

A couple more views:

I'm using a Trollhole replica small courtesy light switch installed in the previously plugged hole in the dash to switch this thing on and off. By the way, in earlier FJ40s this little knob is installed on the right side of the pocket (glove box). My FJ40 has no holes in the dash to the right of the pocket, but I'm able to make use of other holes that are already existing.

The most difficult part about this installation, which also contributed a lot to the overall cost, was the unique connections on the Sanden compressors. The suction side is a 5/8" 45 degree SAE flare. The discharge is a 1/2" 45 degree SAE flare. As an aside, -AN flare fittings are 37 degrees and are not compatible with SAE flare. You can find fittings for SAE flare at your local Ace Hardware, but the only female fittings available are tube nuts. So I would have to get hard tube, flare the ends, and make some adapters if I want to go to any other type of fitting, like to barbs or NPT. Luckily I found some pre-fabbed swivels that helped me get to my NPT connections that I needed so I didn't have to fab up anything myself.

For the air connections, you can commonly find 3/8" and 1/4". I decided to go with ¼” because it seems to be more common. There are also different types of end connections, and I went with I/M as it’s supposedly the most common.

Parts from Ace:
Upper left: Quick-coupler: $4.99
Upper middle: Quick-coupler plug: $1.99
Upper right: Air chuck: $2.99 - Returned this to get one with a clip.
Middle left: 150 psi relief valve: $10.29
Middle: 5/8" SAE flare to 1/2" MNPT 90 degree elbow: $8.49 - for the suction side.
Middle right: 1/2" SAE flare swivel: $9.99 - basically two 1/2" flare nuts with a short piece of tube in the middle, pre-fabbed for the discharge side.
Bottom left: 5/8" SAE flare swivel: $9.99 - for the suction side.
Bottom middle: 1/2" SAE flare to 3/8" FNPT: $4.29 - I can get a Viair 3/8" hose and thread it right into this connection on the discharge side. - Returned this because I needed an elbow - not enough room.
Bottom right: 200 psi pressure gauge: $7.99

More Parts:
Air Hose (50 ft PVC) from Lowe's: $14.02
Manifold from Amazon: $24.02 after shipping
Filter/Coalescer from Amazon: $79.49 after shipping vs. $115 for the one on Kilby's site. This one is made by Interstate Pneumatics, has a metal bowl, and is rated to 300F.
Inlet Filter from Amazon: $30.15 after shipping vs. $28 for the one on Kilby's site. This is the same manufacturer (Solberg) as the one on Kilby's site and I'm assuming it's the same model. It has the same thread connection and is rated for 12 scfm. Heck, the one on Kilby's site may be the one rated to 10 scfm, so if that were to be the case this would be an upgrade. The next largest one is rated to 20 scfm and has a 3/4" NPT connection, which I didn't want. Hopefully this will work.
Air Chuck w/clip from Amazon: $10.37 after shipping
2 x 1/2" FNPT to 5/8" hose barb adapters from McMaster-Carr: $7.52 - this hose barb size is hard to find, but it's what I wanted because I don't want the hose to collapse. Maybe it will anyway and I'll have to redo the suction stuff.
3/8” Viair leader hose with integrated check valve (24” long) + 90-120 psi Viair sealed pressure switch from 4WheelParts: $50.61
30A relay and 2’ of 5/8” ID hose from O’Reilly: $8.08

From Ace:
1/2" flare to 3/8" MNPT 90 degree elbow: $4.49
3/8" coupling for above because they didn't have the above in FNPT: $4.29
Another quick coupler/plug set: $7.49
A couple hose clamps: $2.58
Some sheet metal for mounting the inlet filter: $6.29
3 x 1/4" NPT hex head plugs
3/8" x 1/4" reducing coupling
3/8" short nipple
2 x 3/8" 90 degree elbows
2 x 3/8" x 3" nipples
3/8" x 1 1/2" nipple
1/4" short nipple
1/4" x 1/8" reducing coupling

Total: $361.89, not including the compressor. So it’s pushing $400. Not really any way around it.

More expensive than a couple Viair 12V compressors, but I don’t want a Viair 12V compressor.

I'll need to find the receipt for the belt, sleeve bearings, compressor oil and teflon tape I had to buy, and the compressor was donated for the project but can be had anywhere from $30-$50 at a junkyard.

Here’s pictures of the assembly of the fittings on the compressor.

On the inlet, I have my 5/8" SAE-5/8" SAE swivel fitting, 5/8" SAE-1/2" MNPT 90 degree elbow, and 1/2" FNPT-5/8" barb all connected and ready to go.

On the outlet, I have my 1/2" SAE-1/2" SAE swivel fitting, 1/2" SAE-3/8" MNPT 90 degree elbow, 3/8"-3/8" coupling, and 3/8" Viair leader hose with integrated check valve all connected and ready to go (NOTE THAT THE CHECK VALVE IS BACKWARDS IN THIS PHOTO):

 

[subzali]

Here’s some pictures of the inlet filter:

Here’s some pictures of the coalescing filter:

For the inlet filter, I wanted to mount it high, and preferably not drill any holes. I got some 22 ga. Sheet metal from the hardware store and came up with this bracket that mounts to the air cleaner using the screws for the Hot Air Intake valve:

I had to lower it a little bit to avoid the hood:

It has a little bit of flex, which I was worried about, but I can stiffen it up if need be, and after I put the hose on the filter I found that it's actually pretty stiff and helped hold the filter up a bit. I should probably get a rubber washer or something to put under the filter so it sits on the bracket square and tight, but at least it's secured on something for now. So the inlet air filter is 1/2" MNPT. I have a 1/2" FNPT to 5/8" barb fitting under it, then a 5/8" hose to the fittings on the compressor. I hope the 5/8" hose is stiff enough that it won't collapse under vacuum. We'll see.

Oh and BTW, this thing barely clears the hood. I measured as best I could, but in the end I think I just got lucky.

For the outlet filter/coalescer, I have this c-channel that I made out of the remainder of the 22ga. that I bought running down to the angled part of the fender, and have a couple bolts running through it. It is supporting a pipe nipple on the inlet side of the filter, as close as I can get to the filter. I’m going to need to use some welting or something to prevent rubbing between the support bracket and pipe, haven’t got that on yet.

 

[subzali]

For the air manifold, I needed to raise it about 1 1/2" off the fender, so I made up a couple other little brackets for that. I made some webs on them to stiffen them up as well.

Mounted up, this thing sits really close to the hood support rod. I knew that was going to be the case, but I got it just in the perfect spot. It's not so much a problem with my manifold but more with the pressure gauge and pressure switch, I had to be a little careful where I put those. I had to get a little creative with the brackets as well because of the VSV that one bracket has to share mounting points with. I used existing holes in the fender to mount these.

I changed the routing on my leader hose a little to avoid the exhaust manifold, but now it's really close to the brake pressure switch wire. I'll have to keep an eye on that and see what happens.

I lowered my 31x10.50R15 Goodyear MT/R to 12 psi, and then did a test at 900 rpm (had the choke on slightly). It took 2:45 to air up from 12 psi to 36 psi. Not extremely fast, but respectable. It’s putting out about 5 cfm at that rpm, so it could certainly do more if needed.

Here’s a low-quality video:
OBA Test 1

All in all, I’m pretty happy. Eventually I’ll probably add a little receiver somewhere to increase the tire fill rate, and maybe run an in-cab pressure gauge, hand throttle, and maybe change the quick-connect location to somewhere more convenient to access, where I wouldn’t have to pop the hood. But for now it’s good. I still have to put some heat shields on the exhaust manifold and make some adjustments to the coalescing filter support bracket. But there’s always small tweaks that need to be performed with any mod.

 

[Hugh Heifer]

Hence, the Sanden compressor. Found as an A/C compressor in some Fords, Volvos and possibly other vehicles, it has a slightly lower CFM as compared to Yorks, is tubular in shape which saves space, and the only "drawback" is that you have to add oil because it's designed to be lubricated by refrigerant like an Aisin compressor. But there's a port on the top that allows you to do that, so it just becomes part of pm.

It is my understanding there is not enough oil in there to allow it to run for very long without burning up. You will need to continue oiling it while running or risk failure. I also do not see an on pressure board tank (unless I missed it somewhere) so that will make the pump work all that harder.

Radioridge had one on his truck and even with oiling it burned up after a few minutes of using a die grinder. We were at Harbor Freight the other day and couldn't locate anything to use as an oiler. I have not looked to see what others have done to oil the Sanden compressors.

Other than that, nice bit of fabbing there and good info on the mounting.

Edit: Here is a good idea for oiling. (I see, subzali, you already have that link in your other thread)
http://www.grungle.com/endlessair.html

 

[spressomon]

I tapped the bottom of the coalescing filter to 1/4NPT and then ran a return line back to the fill plug of the Sanden with a mini-ball valve in between. When the oil gets to 1/3 on the sight glass then slowly open the ball valve, so not to blow oil back through your air filter, to pump the oil back into the Sanden.

I also run a 1 micron vapor filter downstream of the coalescing filter...not necessary for filling tires but nice for other applications where oil vapor isn't desired.

Also...its a good idea to use high temp hose on the discharge/output side...and place the coalescing filters far enough downstream from the compressor so the oil has a chance to cool some...

Here's a link to the grease mod (using grease instead of oil)...not sure I want to go this route but other's have successfully.

Greasing a sanden - Page 2 - S-10 Forum

And they are fast indeed! My SD7 at 1500 engine rpm will inflate my 285 width 35" MT/R from 18 to 50psi in under 90-seconds.

Nice write up!

 

[rusty_tlc]

Unless you are willing to sacrifice a lot of space, I see little benefit to a pressure tank for most off road applications. I just don't think the tanks most people run have enough capacity to do much good.

 

[subzali]

Right now I don't have a tank. Wanted to keep it simple for now, and figured that its most likely use will be to air up tires. Don't really agree that the compressor will work harder without a tank though.

Red Fox has been using his Sanden compressor for years and has had no problem airing it up once in a while. I figure oiling it once before every run will be more than he does, but I'm sure time will tell. I can get an automatic tool oiler later on if I want or do the grease mod.

I've thought about the oil return to the compressor, but that was more complication than I wanted for now. We'll see how much accumulates. I'm also a little worried about recirculating water back to the compressor, even though it's a dry climate here in Colorado, for the most part. The filter bowl has a drain in it already.

The leader hose is a Viair that I assume is rated for the temperature that it may see, the coalescing filter is rated to 300F and is about 2' of hose length away from the compressor, so I think that should be sufficient.

 

[subzali]

After doing a couple snow runs and airing down to about 12 psi in all 4 tires, I did some more timing of the fillup to 36 psi. At about 1000 rpm (using the choke) it takes about 1:30 for each tire. It's pretty consistent now, not really sure what the deal was with that first test. Super happy with it, and after a pretty rough ride on Rollins Pass Road/Jenny Creek here in CO it has faired well so far.

 

[Jetboy]

I burned through a couple OEM nippondenso A/C compressors on my minitruck. Oiling is a big problem with anything but a York. A buddy has successfully used a GM OEM compressor with a oil separation filter set along with an inline oiler. The combination seemed to work pretty well. Mount the oil separator above the inline oiler so it will drain naturally into the oiler. An inline oiler is only about $15 or so. Easy to install. Can't see a reason not to use one. Same for a filter. I don't want oil accumulating in my tires.



Good luck.

 

[sggoat]

Been thinking about this mod for a while. Thank you for posting such a complete install.

 

[gregnash]

So after having this for a few months how are you liking it?
I have an FJ60 that the smog pump died in, luckily I live in a no emissions county and the guys in my local club have convinced me that I need to replace it with one of these Sanden compressors instead of a plain pulley.

- Did you ever figure out a better oiling situation for it so you would not burn up the compressor?
- All together the total cost for you was about $400, right?
- If you could change anything what would you change?
- How many banana job is this? I am still new to a lot of wrenching so don't want to get in to deep and then screw myself.

 

[subzali]

I'm still liking the Sanden, though I've only used it a handful of times. It airs my tires up from 12 to 36 in about a minute and a half each. For airing up tires I don't think I need a tank.

-I still oil it each time right before going out on a trail run, seems to work fine.
-All in it was about $400.
-If I were to do anything different I would buy more stuff directly from Kilby Enterprises. For example, the filter they have is more expensive, but it's smaller and lighter weight than the one I have.
-It's a 1-2 banana job. You shouldn't have any problems that will "screw you" because your air pump is on its own belt. Mine shares a belt with my power steering pump, so I couldn't drive it until I found a belt that would work. You can mount yours and hook it up, or not, for as long as it takes until you can piece together the rest of the system.

-I still need to build a heat shield to protect the compressor from the exhaust manifold, I want to put in an indicator LED so I know when the compressor switch is pulled (in case I forget I'll have a reminder), and having an air chuck accessible so I don't have to open the hood would be nice. That's about it.

 

[spressomon]

^ FYI Kilby sells the Coilhose brand coalescing filter...you can typically source them for less and not have to deal with Kilby. Wilkerson makes decent filters too.

 

[gregnash]

Well Spressomon, looks like we might have a new "guinnea pig" for the club on this! Was actually talking with my mechanic buddy about doing this while I was working on his mtn bike (he did some welding for me so I did some bike work) and we got to talking about some of the things I wanted to do to BeBe. Think once things warm up a bit he and I are headed to the PnP down here to see about finding one of these Sandens. He recently got laid off so he is just doing jobs on the side to make the mortgage payment but is interested in helping me with this stuff.

 

[spressomon]

2-1/2 years on my Sanden OBA and it works great. I've used a few different Sandens and learned a few things from this experience.

Let me know if you have any questions.

https://forum.ih8mud.com/showpost.php?p=8090081&postcount=11