Cheap electric compressor - add a tank??

[setsuna]

has anyone got experience (or thoughts/comments) on the operation of one of those $100 cheapy air compressors - but adding a storage tank?

would it help? or hinder?

I figure I could run it prior to needing to inflating the tires, and have a 40litre tankload @100psi head start on the job.

but then would having the tank there slow compression once the tank has filled the first tire??

any thoughts? worth testing out? or an outright waste of time!

cheers

David.

[Lotz-A-Landies]

Would work for low volume jobs like tyres but you would soon run out of air, even with the additional reservior, with high air-flow tools like rattle guns or sand blasters.

Save the money from the additional reservior and use it to buy a better compressor.

[bee utey]

Fill the tank anytime, have a ball valve on its outlet so you can isolate it from the pump. That way you can pump the tank at a servo, have air whenever you need it. The valve reduces the chance of it all leaking out before you need it.

[HBWC]

i've done it with a 24lt tank and it works well for the firsr 2 and abbit tyres then slows down to normal speeds well worth it

[Blknight.aus]

Ive done it.

works like a charm of course the better compressor you use on it the better it works as you dont waste time between tyres with the compressor off.

if you get a cheap compressor at a garage sale rat the pressure control switching module and use that to control the compressor and then you can have it on all the time when you fourwheeling.

[setsuna]

Thanks for the good advices! will be definitely keeping an eye out for the bits to add the tank!!

David

[banjo]

My old series2a with holden 173 had an old aircon pump with a filter on the inlet & a quick conector on the outlet ,you just pluged the hose in flick the switch & away you go it use to pump my 31x10.5 x15 up in about 30 seconds.
Its best to use a aircon pump with a sump on the bottom mine was off an MQ nissan worked for me didnt need a tank...

[setsuna]

yes I was looking into that option too.
best to use the existing mechanical energy there ;)

but the oiling of the inlet air, and the removal of the outlet air scared me off.
I didn't know there were pumps with internal lubrication?!

David

[Blknight.aus]

yep the older style york recipircators are the best for it.

took one to the cape.


http://www.aulro.com/afvb/projects-tutorials/76829-12v-compressors.html

[TonyC]

Also have a look here if you are interested in setting up a york unit.

York Compressor for On-Board Air (http://www.jedi.com/obiwan/jeep/yorkair.html)

Jon's Place/Jeep Page (http://www.huv.com/jon/jeep/Air/index.html)

Tony

[paulthepilot_5]

yes I was looking into that option too.
best to use the existing mechanical energy there ;)

but the oiling of the inlet air, and the removal of the outlet air scared me off.
I didn't know there were pumps with internal lubrication?!

David

The sanden compressors will still run fine if you just give them a good squirt of oil now and then. I have been using a sanden to run air tools from my landy for a while now. An air tank will seperate the oil from the air well, as long as the air line from the compressor, and the outlet on the tank are seperate.

Paul

[setsuna]

great info guys!
more things to keep an eye out for at the scrap yard!

are they hard to find nowdays? if I find a few ill scrounge them and offer them up on here.

Blknight, I LOVE your compressor. just the danger of probably almost getting killed everytime you use it (belts, moving parts, high pressures, current, explosions and fire! especially if located near to fuel tanks!!) make a mundane task of reinflating tires exciting!!

David

[Blknight.aus]

great info guys!
more things to keep an eye out for at the scrap yard!

are they hard to find nowdays? if I find a few ill scrounge them and offer them up on here.

Blknight, I LOVE your compressor. just the danger of probably almost getting killed everytime you use it (belts, moving parts, high pressures, current, explosions and fire! especially if located near to fuel tanks!!) make a mundane task of reinflating tires exciting!!

David


theyre not all that common but they are out there, I have 3 one is US unless I find a valve plate for it one is in the pump that I made the second larger unit was to be mounted to fozzy.

others work just as well but need some minor mods to make the suitable for long term use

as for getting killed when using it.

Welcome to australia, you might accidentally get killed anyway might as well have it happen having some fun.

YouTube- Deadly Animals (Come to Australia)

[VladTepes]

The only problem with aircon ones is if you already have air con compressor to run, oh i don't know.. air con !

I've got a Bushranger compressor and was going to set up a reservour tank in the 130 just need to work out what bits I'll need, what size air tank etc.

[setsuna]

"stick it where it fits"

and.

"make it as big as possible!"

eyeball engineering =)

I am thinking a scuba tank will fit the bill. being aluminium, thin, but long, and of a decent capacity.

David

[agrojnr]

I have this type

BOSS Air Compressor PX-07 (http://www.4h.com.au/prod136.htm)

They do draw alot of power but they are very good units plus I have a 24L tank and 130psi pressure switch

Adam

[HBWC]

if your looking for york compressors try 2 series volvos their a bit more common than people think

[VladTepes]

2 series volvos - you mean the air con compressors from those, or did they have some sort of useless EAS ?

[bee utey]

2 series volvos - you mean the air con compressors from those, or did they have some sort of useless EAS ?
We're talking 75-85 model years here, 4 cylinder volvos had York air con compressors on them. No EAS, they are just a swedish kingswood you know.

[VladTepes]

We're talking 75-85 model years here, 4 cylinder volvos had York air con compressors on them. No EAS, they are just a swedish kingswood you know.

Not the Kingswood !!!!!!!!!!!!!!

[HBWC]

any of the 2 series 4 or 6

and the cars they can be found in
244
242
264
262
and just got of the phone to a volvo freek and he said the 1 seres
had them to

[Blknight.aus]

"stick it where it fits"

and.

"make it as big as possible!"

eyeball engineering =)

I am thinking a scuba tank will fit the bill. being aluminium, thin, but long, and of a decent capacity.

David

too wide for most places and too heavy for the pressure you need.

LPG tanks work nicely as do gas bottles, even the little primus hand torch bottles are good value.

[setsuna]

oh I imagined it would be very light seeing it has to be carried around.

I think it would fit nicely next to the chasis rail on the Disco!

will take a look around and see what is available ;)

David.

[Blknight.aus]

nahh scuba tanks weigh a motsa even the "lightweight" aluminum ones what makes them appear light is that they are generally carried around on the back and in the water they get a good chunk of buoyancy from being in the water which makes them very easy to swim around with. (but they to take a lot of air onboard if you can pump them up to rated pressure)

I had similar ideas when I started diving but the skinniest tanks (excluding pony, some exotic tanks designed to be used in gangs and re breather bottles) are further across than a the depth of the series chassis member.

SCBA units from the firefighting trade are a fiberglass like tank and are very light but dont take too well to abuse. I would suggest that the very best bet for a tank will come from a truck wreckers or small 240V compressors.

other things you will need are a pressure switch and the plumbing. If you got the 240 compressor to donate the pressure control switch you usually also manage to score a safety valve, one way check valve, a regulator and an outlet fitting. They (both the truck tanks and the 240v compressors) also tend to have mounts prewelded to the tank so that an amateur hack welder can mod the mounts to fit the tank where it needs to be.

[slug_burner]

Lots of tanks available at any truck wrecker. I got this one for $15, gave it a lick of paint made up some straps and hung it off the the chassis rail under the drivers seat.

Some like the idea, others prefer to use their rock sliders and use the space for long range tanks etc. I don't have any extra fuel tanks so the space was going begging.

https://www.aulro.com/afvb/images/imported/2011/11/930.jpg

[George130]

The idea works well. I have a 24lt tank with cheap compresser. Turn it out when I head out and can inflate 2 tyres before it gets quite slow. Compressor kicks in at 80psi and cuts out at 100 psi. I'm looking at fitting a second tank.

[agrojnr]

Wait till council clean up days and see if anyone throws out an old compressor to use as the tank, thats all mine is

Adam

[bee utey]

any of the 2 series 4 or 6

and the cars they can be found in
244, 245, 240
242
264
262
and just got of the phone to a volvo freek and he said the 1 seres
had them to

Volvo 262 ,264 and 265 ran the GM AC Delco compressor, a dinosaur of a rotary compressor, my mate the a/c man hates them. Great car, shocken engine.
Yorks are also found on Fords up to XD 6cyl or XE V8

[mark2]

While the Yorks have a sump, they are big and bulky and harder to find. The Sandens work just fine and are everywhere. A $5 inline oiler from Bunnings clamped on the end of the inlet is all you need.

If its just going to be used to inflate tyres, you'll find that a tank isnt really necessary if using an ac compressor. Even at idle speed, my Sanden inflates tyres virtually as fast as my 16 cfm workshop compressor. Once the compressor gets over a certain capacity, the flow restriction at the tyre valve is the limiting factor. I have a truck air tank sitting in the shed but cant see any benefit in fitting it until I need to run mobile air tools.

[VladTepes]

Yes I'd agree that with a decent air con type compressor a tank woudn;t be really needed for tyre work.

[bee utey]

Two main benefits of a tank:

(1) it contains enough air to rapidly inflate 1 tyre, this is especially nice if you have a flat on a busy road and don't want to change it then and there, you can leave fast to get to a safer place. A woman was recently killed on the freeway near Adelaide while waiting for her son to come and change her flat, a truck rammed her just before he arrived. I like the idea of getting off the slip lane quickly.

(2) you can get to run a real horn, one of those chrome trumpet things, I had one in my old P76. When approaching mobile hamburgers in the Riverina, if you tweet like a Corolla they ignore you, honk like a Mack and they jump out of the way!:D

[VladTepes]

mobile hamburgers ?

[bee utey]

mobile hamburgers ?
Beef cattle

[Blknight.aus]

pedestrians, cows, sheep anything else made of meat that moves.

[mark2]

Two main benefits of a tank:

(1) it contains enough air to rapidly inflate 1 tyre, this is especially nice if you have a flat on a busy road and don't want to change it then and there, you can leave fast to get to a safer place. A woman was recently killed on the freeway near Adelaide while waiting for her son to come and change her flat, a truck rammed her just before he arrived. I like the idea of getting off the slip lane quickly.

(2) you can get to run a real horn, one of those chrome trumpet things, I had one in my old P76. When approaching mobile hamburgers in the Riverina, if you tweet like a Corolla they ignore you, honk like a Mack and they jump out of the way!:D

I saw a train horn for sale at a swap meet recently:eek: Only problem was, I would have needed to fit a pair of roof racks just to mount the thing...

[VladTepes]

and a VERY big air tank !

[setsuna]

did a test on the weekend on the ebay special compressor.
I connected it up to my little portable compressor tank and let it blast.

a little dissapointed with the results: (maybe I shouldn't be?)
I let it run for 5minutes. it managed to get the 30litre tank up to 50psi.
the first ~30psi went pretty quick and after that it started to struggle.

it'll do okay for this trip, until I can sort out propper air :D

oh I also picked up an inline oiler for experiments in the near future :D:D
- all depending on which compressir I am able to get (and fit)

David

[bee utey]

I saw a train horn for sale at a swap meet recently:eek: Only problem was, I would have needed to fit a pair of roof racks just to mount the thing...
Fit it up to the exhaust instead...

[discomuzz]

Just found two York AC compressors at the local wreckers.

Both on early Range Rovers as chance would have it.

$50 each.

I am keeping one so If anyone out there wants the other let me know and for the cost of postage and half a dozen cold stubbies I'll grab it.

[Blknight.aus]

any chance of getting you to go back and purchase the brackets as well.

Happy to lay on dollars for the parts/transport and help out with setting up your tank in exchange for the efforts

[discomuzz]

any chance of getting you to go back and purchase the brackets as well.

Happy to lay on dollars for the parts/transport and help out with setting up your tank in exchange for the efforts

Yet to grab them. Happy to get the brackets for you. Not sure which model's they are. Does it matter?

Assume the wrecker won't add extra for the brackets, so should still be the $50 bucks + etc.

All help would be greatly appreciated.

PM your details and I'll get to work.

[Blknight.aus]

22822
heres my effort from a $99 12v compressor and an $80 240 compressor out of the bargin bin from kmart
its had a couple of mods in its time but its got to be at least 7 years old now

the only thing thats not in the picture is the male-male fitting that goes on the back of the compressor to the tank when I want to use it via the tank.

[discomuzz]

Nice!

I have a complete Supercheap 20l compressor minus the pressure switch/regulator gizzmo which carked it (more expensive than a new compressor).

With the tank and the York I want to setup air on my Mitsubishi Canter to run a big-as air horn and some sort of air brake assy. for the tail shaft as the mechanical handbrake on it is next to useless.

If this is not a goer, I have a 5HP B&S horizontal shaft motor sitting in the shed which I thought might pair-up with the York to make a nice portable spray gun/rattle gun unit.

Any ideas?

[Blknight.aus]

thatt'l work nicely....

yeah I've got some ideas

[discomuzz]

Actually, I will be happy to run a big-as air horn on the truck!:twisted: (Someone mentioned a train horn, mmmmm)

I'll get to the wreckers on Wednesday.

So, you want one of these units?

[Blknight.aus]

no, I have about 6 belt drive compressors that are all suitable for engine mounting but the new thing has a rangie 3.5 in it and no mounts for the aircon compressor...

Im sort of halfnhalf do I give the missus aircon or fit a mansize compressor....

either way I need the mounting bracket for the compressor.

[discomuzz]

Cool!

I'll get the brackets and send them up!

Thought you wanted the whole unit.

Easy done.

Just cover the postage and I'm sweet.

[Blknight.aus]

drop me a PM when youve got em off and I'll get you to send em up COD or let me know the costs and your account details and I'll do an electronic transfer for ya.

[DEFENDERZOOK]

i didnt read through all 5 pages.......im about to go to bed now so cant be stuffed.....
this may have already been mentiond......but here goes anyway.....


if you are inflating a tyre......the maximum pressure you inflate to will be around 40psi.......ish......

if you run a tank.....at say 100psi for arguements sake.....the compressor will have to run a lot longer....and harder....just to get to that pressure.....
this will cause it to heat up a lot more than if it was connected straight to a tyre.....

and being a cheap compressor.....do you really want to stress it that much.....?



ive thought about all this......and simply came up with.....whats the use....?
if you can pump your tyres up faster....youll only be bored longer than everyone else thats still inflating theirs.....
youll still have to wait for them anyways......
or you end up using your compressor to pump someone elses tyres cos you finished first......like i end up doing......

so heres my idea......invest in two cheap compressors........and connect them together......this will give double the volume of air.......
you can pump up a tyre twice as fast......or you can pump two tyres at the same time......

and if one dies......you still have one working......

a reservior is needed if you want to run air tools or air lockers......


just some of my thoughts and ideas.......

[bee utey]

All good observations, Defenderzook. However the one thing your York compressor is good for is pressure. They don't slow down much until over 250psi so a pressure switch is very important. They can save a lot of time.

On the positive side, fast tyre inflation time gives you time for other important jobs, like having a beer.

On the negative side, everyone else will want to use your fast tyre inflation system.

[Blknight.aus]

i didnt read through all 5 pages.......im about to go to bed now so cant be stuffed.....
this may have already been mentiond......but here goes anyway.....


if you are inflating a tyre......the maximum pressure you inflate to will be around 40psi.......ish......

if you run a tank.....at say 100psi for arguements sake.....the compressor will have to run a lot longer....and harder....just to get to that pressure.....
this will cause it to heat up a lot more than if it was connected straight to a tyre.....

and being a cheap compressor.....do you really want to stress it that much.....?



ive thought about all this......and simply came up with.....whats the use....?
if you can pump your tyres up faster....youll only be bored longer than everyone else thats still inflating theirs.....
youll still have to wait for them anyways......
or you end up using your compressor to pump someone elses tyres cos you finished first......like i end up doing......

so heres my idea......invest in two cheap compressors........and connect them together......this will give double the volume of air.......
you can pump up a tyre twice as fast......or you can pump two tyres at the same time......

and if one dies......you still have one working......

a reservior is needed if you want to run air tools or air lockers......


just some of my thoughts and ideas.......


thats why my aircompressor on the tank has the removable fitting for charging the tank or running direct.

[DEFENDERZOOK]

i wasnt talking york compressors......i was talking electric compressors.....

if only i had a york......theres no room under my bonnet.......they couldnt even fit a battery under there.....
that had to be stuffed under the seat.......





maybe i could fit a compressor to the PTO.......

[Blknight.aus]

zooky, the compressor in post 42 (cool uninetntional guide reference) isnt the yorkenstein compressor from fozzy its my portable one that I use when Im not planning on having to change tyres, strip whole vehicles or having to inflate a small convoys worth of rubber.

its usual duties include running the air duster when Im working on small bits in the field, inflating tyres and blowing out fuel/oil lines. (its also been used to air up an R series Mack start tank)

[It'sNotWorthComplaining!]

I found this The tutorial uses a Sanden compressor.... From old Rangie A/c
Onboard Air system for a 200 Tdi Defender, using a Sanden compressor.

Onboard air systems using converted air conditioning compressors have considerable benefits over the usual 12v electric compressors. The best of the 12v models will produce a max of about 3cfm, whereas most air con compressors can comfortably produce at least 8 cfm (some as high as 12.5cfm), and do it on a continuous basis, unlike the limited duty cycle of the 12v models.

There are two basic types of compressors used in automotive air conditioning.

Less common nowadays is the York type compressor. These are 2 piston reciprocating compressors and are generally of a higher output than the rotaries, and also have the benefit of a separate oil sump which can be converted to be isolated from the airflow of the compressor. The downside of the York style is the sheer size and weight of the unit. This makes fitting difficult in most Landrovers, which don’t usually have a lot of spare space in the engine bay.

More common is the rotary compressor, using either 5 or 7 cylinders mounted on a rotating wobble plate. Of these, the Sanden brand is the most common. Although generally of less capacity than the Yorks, the Sanden compressors still produce either 8 or 10cfm (at 2000rpm), depending on the model used. The Sandens have both an upside and a downside for use as an Onboard Air system:

The downside is that they rely on lubrication from an oil charge that travels around the system with the refrigerant gas, and cannot be converted to run a separated oil sump. However, this can be addressed by using an air tool oiler to feed oil into the compressor intake to provide the necessary lubrication. To remove this oil from the compressed air output, a coalescing filter is used. These filters will remove both oil and moisture from the compressor’s output, ensuring only clean, dry air reaches the storage tank (and your tyres).

The upside is the compact size and shape of the Sanden compressor. In vehicles without Air Conditioning already fitted, it often is simply a matter of getting hold of the factory A/C mounting brackets and using them to mount the compressor as you would for Air conditioning. If A/C is already fitted, then it’s usually possible to mount the extra compressor off the side of the A/C compressor. This is what I did in my Tdi Defender.

So, first off, the schematic:

https://www.aulro.com/afvb/images/imported/2010/02/2.jpg

Here you can see both the air flow and electrical for my particular system.

The compressor draws air in through the oiler (to which I also attached a small cheap K & N type filter), which will add a small amount of oil to keep the internals of the pump happy.

Compressed air is then sent via a coil of pipe (in my case aluminium, but copper would be good too), before arriving at the check (or non-return) valve. This will ensure that when the compressor isn’t pumping, the air in the tank will not flow back past the pistons and out through the intake line. The purpose of the coil of pipe is to function as a cooling line. The compressed air coming out of the compressor will get extremely hot, 150 deg C or more. At this temperature many of the downstream devices (filter, check valve etc) are a bit at risk because they contain some plastic parts. More importantly though, the filters function more effectively on cooler air and we don’t want oil getting past into the tyres.

Once past the check valve, the air passes through the coalescing filter which will remove the oil and any moisture present, before reaching the manifold. I’ve used a manifold arrangement simply as a convenient way of mounting the pressure switch, safety valve and feed for a pressure gauge in the engine bay.

What do these things do?

The pressure switch does pretty much what you would imagine from the name. A simple electrical switch that will cut the power feed to the compressors magnetic clutch (and hence stop it pumping) when a preset pressure is reached. Likewise, when the pressure drops to a lower preset level, it will then trigger the power back to the magnetic clutch and start the compressor pumping again. In my case the pressure switch is set to cut in at about 80psi and cut out at about 120psi.

The safety valve is vital in these systems and is simply there as a back up in case the pressure switch for some reason doesn’t cut the power to the compressor once the 120psi limit is reached. These compressors are fully capable of pumping well beyond 200psi, and can exceed the safe level for things like your tank and hoses. Obviously it would get a bit exciting if this were to happen and you had you air tank blow apart because the compressor didn’t know when to stop! The safety valve is preset to release the line pressure if it exceeds 150psi. As I said, absolutely vital for safety’s sake.

The feed for a pressure gauge is exactly that. I’ve just mounted a small pressure gauge in the engine bay so I can see what’s going on. This is temporary for me, I intend to mount a nice VDO type gauge in the dash eventually and I’ll take the existing one out altogether.

Step 1- Mounting the Compressor

I thought this would be the easiest part of the whole job, but the tight confines
of the engine bay made it a bit of a challenge.

The first part of this exercise was to alter the head of the pump to make hookup easier. Air conditioning compressors usually have an odd type of thread and flare fitting for connection of the inlet and outlet hoses. Also, these fitting are quite large and I knew I didn’t have a lot of space to operate in. My solution was to take the head off the compressor and cut off the threaded section for the flare fittings. I then drilled and tapped the holes so that I could fit normal threaded brass elbows and barb fittings.

The typical compressor with the large flare fittings:

https://www.aulro.com/afvb/images/imported/2010/02/3.jpg

My modified compressor with the threaded bits cut off, and drilled and tapped for normal fittings. The fittings installed are just there temporarily to keep muck out of the holes:


https://www.aulro.com/afvb/images/imported/2010/02/4.jpg


Since the Sanden unit had exactly the same mounting dimensions as the existing Diesel Niki A/C compressor, my idea was to mount it off the side, using the lug mounts on each compressor to both mount and pivot from. That would enable me to fit a slotted flat bar for belt tensioning, much like many alternators do.

Reality in the form of lack of space soon put paid the Mark 1, so Mark 2 was invented that utilised a tensioning pulley purchase for an automotive A/C parts supplier.

Here’s the compressor mounted up:

https://www.aulro.com/afvb/images/imported/2010/02/5.jpg

A close up of the small brackets linking the two compressors together:

https://www.aulro.com/afvb/images/imported/2010/02/6.jpg

The underside:

https://www.aulro.com/afvb/images/imported/2010/02/7.jpg

The bracket holding the tensioning pulley:

https://www.aulro.com/afvb/images/imported/2010/02/8.jpg

The tensioning pulley from behind:

https://www.aulro.com/afvb/images/imported/2010/02/9.jpg

Having thought I'd cleverly solved the mounting and tensioning problem, I then closed the bonnet. Bugger, the bonnet stay folds neatly against the newly installed belt. Didn't think that one through very well. Fortunately, the stay has a lot of flex in it, so a small length of flat bar was bolted in place to guide the folding stay away from the belt. Some rubber strip stuck to the stay stops any rattles (which we don't want in a Defender):

https://www.aulro.com/afvb/images/imported/2010/02/10.jpg




Step 2 – Installing the Cooling Loop

I originally intended to use a line of ½ inch copper pipe tucked under the front wing somewhere as a cooling line. However, I just happened to be around for the decommissioning of a large industrial compressor which had cooling coils mounted on the output of each of its cylinders. It actually had four cylinders with a separate coil on each one. Obviously one of these (which is about 2 metres long if straightened out) was meant for Landrover service:

https://www.aulro.com/afvb/images/imported/2010/02/11.jpg

It mounted up well (eventually) behind the right front headlight. I made up a simple bracket the mounted from the bolts in the stiffening ribs on the coil to the bracket holding the PAS reservoir:

https://www.aulro.com/afvb/images/imported/2010/02/12.jpg

Step 3 – The Manifold

There are many variations possible with this. Indeed, the use of any type of manifold is optional anyway, it’s just a convenient way of putting together some of the items that you need installed on the output line.

In my case, I chose to mount up the Check (Non-return) valve, pressure switch and safety valve in a manifold constructed from a combination of galv and brass fittings. They were just what I already had in the garage, so cut down on what I had to buy or make.

These three items normally live together in most air compressor environments, so fitting them into some sort of manifold makes sense, but it isn’t essential to do it this way.

Here’s the manifold ready to be installed:

https://www.aulro.com/afvb/images/imported/2010/02/13.jpg


In the above photo you can see the thin black tube running from the Non-return valve to the pressure switch. This is the unloader line. Its function is to release the pressure from the line between the compressor and the Non-return valve, once the pressure switch has reached its maximum level. At this point a small valve in the pressure switch opens up releasing the air via this line. This ensures that when the compressor needs to re-start, it does so without any backpressure, making life easier in the compressor and compressor’s magnetic clutch. It’s not essential to have this in place, but since most pressure switches and non-return valves have the facility anyway, it certainly can’t hurt.

Here’s the manifold installed under the right wing, under that blank plate:

https://www.aulro.com/afvb/images/imported/2010/02/14.jpg


Step 4 – The Intake Oiler and Outlet Filter

I made a bracket to mount both of these on the top of the brake booster. It was about the only space left in the engine bay that was big enough to house them.

In this picture the filter is nearest the camera, the oiler and small K & N type filter for the inlet are on the other side of the brake booster:


https://www.aulro.com/afvb/images/imported/2010/02/15.jpg

From the other side showing the oiler and line to the compressor:

https://www.aulro.com/afvb/images/imported/2010/02/16.jpg


Step 5 – The Receiver (Tank)

This turned out to be the easy part. There are once again a number of options for a tank. Some people have used things like old fire extinguishers, LP Gas cylinders or even purpose made cylinders. I found the easiest (and probably cheapest) was to use the air brake reservoir tank from an old truck. These are usually rated to well in excess of the pressure you’re likely to use, are available in a variety of shapes and sizes, often can be had with the original mounting bracket, and best of all, they’re cheap.

My tank came courtesy of an old Ford Trader truck. I did a quick measure up of the space I had to work with, then visited the local truck wrecking yard. The owner pointed to the trucks and said to go a find the one I wanted. The second truck I looked at was the Ford Trader. It had two tanks, one was far too large, but the smaller secondary tank was just the ticket and my later calculations tell me it holds about 16 litres. The yard owner sent the young apprentice out to take it off the truck for me complete with the mounting bracket. He even gave it a steam clean before handing it over. The price? Just under ₤10.

Here’s the (repainted) tank ready to fit:


https://www.aulro.com/afvb/images/imported/2010/02/17.jpg

My chosen location was behind the left rear wheel:

https://www.aulro.com/afvb/images/imported/2010/02/18.jpg


The outlet from the tank goes to a quick disconnect coupling on the rear crossmember:

https://www.aulro.com/afvb/images/imported/2010/02/19.jpg

Conclusion

So, how does it work?? Well, to say I'm impressed is an understatement! I know the specs say these compressors should be capable of about 8cfm, but it's not until you get the thing running that you see just how serious they are. It takes just under 20 seconds to fill the system, including the 16 litre tank, from empty to 120psi. That includes the almost 2 metres of 12mm bore cooling loop, plus the 12mm hose running to the tank behind the left rear wheel.

The unloader valve works just like it says on the packet, a very nifty pssssst when the 120psi mark arrives and the compressor starts freewheeling. At about 80psi, the pressure switch fires things up again, and before you know it, psssst, we've got 120psi.

With the engine doing about 2000rpm, the compressor can pump air faster than my air duster attachment can let it out of the tank. That'll do me I think!!

Real world use is no less impressive. I timed the compressor pumping up my 33” (255/85r16) BFG M/Ts, from 18 psi to 35 psi, which is what I generally do coming out of the sand. Time taken was just 25 seconds per tyre. Having used the 12v compressors in the past for that very exercise, I can tell you that’s fast!

And this
Air conditioning compressor converted for ‘On Board Air’:

There are two excellent ‘on board air’ articles in the Tech archive, and I thought I would share details of my slightly simplified system together with relevant info for those contemplating such a useful modification.

I have converted a Sanden SD709 Range Rover air con pump for onboard air.

The newer versions which take the more environmentally friendly refrigerants are numbered SD7H15 and are mechanically and dimensionally the same.

The Sanden air con compressors are commonly found on Range Rovers and Discoverys with both V8 and Tdi engines. They come with either V belt pulleys or serpentine belt pulleys depending on age.

All 2.5 diesel, turbo diesel, tdi and v8 engines have the necessary mounting points on the engine (though some diesels don’t have the four mounting bosses on top of the timing case drilled and tapped). With the right factory bracket, tensioner and bottom crank pulley, fitting is easy.

The Land Rover 4cyl petrol engines don’t have the timing case mountings as standard, so I had to make a bracket for my application. I chose to run mine from a second standard water pump pulley bolted on top of the original.

To keep things simple and cheap, I chose not to buy lots of threaded fittings. I welded a short piece of 13mm steel tube to the compressor’s outlet fitting. This is connected to some ½ inch bore rubber air line with some construction adhesive and a jubilee clip. This rubber air line is connected in the same way to a length of standard 15mm domestic copper tube which runs along the chassis. Towards the end of this copper pipe, I fitted a 15mm domestic water system non return valve. This is then connected to another piece of rubber ½ inch air line to the tank/receiver.

For simplicity, I used the complete tank, switch, pressure relief valve etc from a very small workshop compressor (4 litre tank). The pressure switch was adjustable (although these switches are from 240v compressors, they all work fine with 12volts), so I set it to come on at 90psi and switch off at 130psi. The tank fits neatly on top of the rear wheelbox.

Wiring is very simple. A fused ignition controlled supply goes to the on off/pressure switch on the tank, and from here to the clutch on the compressor in the engine bay.

The York compressor (not commonly fitted to Land Rover vehicles) is sometimes chosen over the Sanden because of the rumours that only the York has a sump for oil lubrication. The Sanden also has a 'sump' in that the wobble plate area under the pistons is also designed to be filled with oil in its original air conditioning application.

Just like the York’s sump, this area is connected to the head by a small passage which is designed to let some of the oil circulate with the refrigerant.

Because of the rotary design of the Sanden as opposed to the ‘crank and conrod’ design of the York, the Sanden design works well for onboard air when the ‘sump’ is filled with grease.

This means that there is no need to fit a coalescing filter to prevent oil getting into the tyres.

The valves in the head of the compressor are simple flaps of stainless steel and require virtually no lubrication. For this reason, I didn’t feel the need to fit an inline oiler to the air intake. A little squirt of wd40 or similar into the intake once in a blue moon is all I do.

The simplest way to get grease into the compressor, is to unscrew the top hex filler plug, and put the nozzle of the grease gun into the hole and pump until full-ish, then replace the plug. It may be that the thixotropic swivel housing grease would be good in this application – I haven’t tried it.

I put a filter on the end of my airline to check that no oil or moisture would get to the tyres. The filter never collects anything. I drain off any moisture from the tank before and after each offroad day, and that seems to be all it needs.

Points to note:

You don’t need an ‘unloader’ type pressure switch for onboard air. Compressor will easily cope with full system pressure in the pipe work etc on startup.

You don’t need a tank for airing up tyres, but it helps to collect any condensation/moisture/oil residue from the air, which is therefore prevented from reaching the tyres, and can be drained off regularly.

I used a 15mm domestic water system non return valve (from Toolstation - £1) because the one fitted to the original compressor tank looked small and restrictive. Conventional air ones are readily available but at higher cost.

Domestic copper tube and fittings are perfectly capable of handling the air pressures.

If you use copper pipe, it should be fitted in a way so that it doesn’t fatigue due to flexing/vibration (use flexible hose at either end).

Use rubber or silicone air hose close to compressor as some plastic types may get soft and weak with the heat. If you wanted to run ARB air difflocks, you can either set the pressure switch to keep the system pressure at the required pressure (will reduce tyre inflation performance a bit), or fit a cheap regulator to the system to feed the ARBs, whilst keeping system pressure high for tyre inflation.

I used a cheap K&N style crankcase filter on the compressor inlet (about £2 new from ebay) I have a large plastic aerosol cap which I fix over the filter which still allows plenty of air flow but stops the filter getting splashed with muddy water.

You can use all sorts of different pressure vessels for the tank, eg fire extinguishers, gas bottles, truck air brake tanks, or whatever. Being able to regularly drain them is important.

A pressure relief valve/safety blow off valve is vital in case the pressure switch fails or the clutch fails to disengage.

I enlarged the compressor head and fitting orifices with a drill (this may not have been necessary) and used as big a bore hoses and pipes as I could, in the belief that it would keep any restrictions to a minimum. Fittings where necessary are ¼ bsp and are the narrowest points in the system. Tool airline is 3/8 inch bore.

Performance:

I only have a tiny 4 litre air tank, but my system will inflate a 32inch tyre from Zero psi to 32psi in only 25 seconds (with the engine at around 2000rpm). It will pump air faster than it can go through the tyre valve, so the compressor will turn itself off and on during filling.

Even with such a small tank the impact gun will undo wheel nuts, as long as they aren't over tightened (cheap impact gun – probably not very efficient).

Useful links:

I discovered reasonable value pressure switches, safety blow off valves etc can be bought from Matt Savage at: http://www.mattsavag...ompressors.html (http://www.mattsavage.com/acatalog/compressors.html)

I have no connection etc.

Sanden specs and workshop manual:

http://www.sanden.co...rvicemanual.pdf (http://www.sanden.com/support/pdf/sd7servicemanual.pdf)

Photos:https://www.aulro.com/afvb/images/imported/2010/02/20.jpg (http://forums.lr4x4.com/index.php?app=core&module=attach&section=attach&attach_rel_module=post&attach_id=2697)
https://www.aulro.com/afvb/images/imported/2010/02/21.jpg (http://forums.lr4x4.com/index.php?app=core&module=attach&section=attach&attach_rel_module=post&attach_id=2696)
https://www.aulro.com/afvb/images/imported/2010/02/22.jpg (http://forums.lr4x4.com/index.php?app=core&module=attach&section=attach&attach_rel_module=post&attach_id=2695)
https://www.aulro.com/afvb/images/imported/2010/02/23.jpg (http://forums.lr4x4.com/index.php?app=core&module=attach&section=attach&attach_rel_module=post&attach_id=2694)
https://www.aulro.com/afvb/images/imported/2010/02/24.jpg (http://forums.lr4x4.com/index.php?app=core&module=attach&section=attach&attach_rel_module=post&attach_id=2693)




Have fun with your onboard air!

[setsuna]

well, the ebay special pump struggled through the weekend. does the job, but takes those extra few minutes!! went to the local scrap metal yard and found some treasure!! a reasonably new looking aircon compressor pump from a daewo and a large tanked aircompressor that looked like it has been dragged through the worst days of its life -- had a popup sprinkler for an air inlet/'filter' electrical tape holding the rest of the plastic shrouding on, handle half attached and every bolt on the thing was finger tight.

the tank was way too large to use, but the check valve, pressure switch, unloader, safety valve, and a few fittings will find themself put to a better use than scrap metal :D

David.

[fraser130]

I saw a train horn for sale at a swap meet recently:eek: Only problem was, I would have needed to fit a pair of roof racks just to mount the thing...

I have always wanted a train horn!

[350RRC]

I'd like to hear other's opinions on filling a rotary compressor 'sump' with grease to assist in this application, coz I have one kicking around.

cheers, DL

[It'sNotWorthComplaining!]

I'd like to hear other's opinions on filling a rotary compressor 'sump' with grease to assist in this application, coz I have one kicking around.

cheers, DL
from my post above on this thread.
[The York compressor (not commonly fitted to Land Rover vehicles) is sometimes chosen over the Sanden because of the rumours that only the York has a sump for oil lubrication. The Sanden also has a 'sump' in that the wobble plate area under the pistons is also designed to be filled with oil in its original air conditioning application.

Just like the York’s sump, this area is connected to the head by a small passage which is designed to let some of the oil circulate with the refrigerant.

Because of the rotary design of the Sanden as opposed to the ‘crank and conrod’ design of the York, the Sanden design works well for onboard air when the ‘sump’ is filled with grease.

This means that there is no need to fit a coalescing filter to prevent oil getting into the tyres]

[Bigmark]

I dont know what size but a gasfitter i know uses an old lpg bbq gas bottle- he fitted a compressor hose fitting and tube nipple to it and then fills it up at a garage before he heads off on a trip . he says it fills all tyres up a few times- he said you can also carry a few small ones as spares. Now i know that an lpg bottle hold 260 times the volume of lpg in uncompressed state. im not sure how much air you can fit in the lpg bottle compressed- or if hes having a go as to how many tyre pump ups he gets.

[Blknight.aus]

a 9kg BBQ bottle holds enough air to inflate a 15x10 (the standard "fat" tyre for a series bout 31 inch rolling diameter) from fully deflated to 35psi.

chase down the thread on my home brew compressor theres one on there that I use as a combo shooter tank and compressor tank.