300Tdi Motor Driven Air Compressor

[MinniTheMoocha]

Hi all,

Just wanted to give you a heads up on a 300Tdi air compressor that was fitted up this weekend.

It is a prototype (but is already running on a 300Tdi Disco) so although I am the guinea pig in a Defender it has been successfully tested already.

What's different from the existing 300Tdi Disco setup is the A/C mounting bracket that incorporates another A/C unit converted to being just an air compressor.

It takes air from the air inlet pipe post air cleaner (although it could come from the the oil separator can on the rocker cover to automatically oil it) Instead this is going to have an electrical timer fitted so that I can just grease/oil it after running the unit for the desired length of time, currently going to run it for 5 hours between lubrication.

I have fitted up a 15 litre aluminium tank under the driver attaching it to the chassis using some steel brackets made up to clamp it. (I did not want to weld or drill holes into the chassis).

What is really great is that it pretty much leaves the Defender stock standard except for running a longer 4Pk belt to cater for the extra run around the new air compressor pulley and having to straighten the scissor bonnet stay.

Initial testing has been pretty good, airing up my tyres (235/85/16) from 15Psi to 50Psi averaging about 2 minutes just at idle. This used to take me over 35minutes with the older style AR@ unit that was fitted to my truck. So this really is a step up! I intend to rerun the test at 1500rpm.

It has taken a fair amount of work from a number of people with the majority being Steve, "Madana" who has meticulously designed the new A/C & air compressor bracket as well as source the A/C unit that fits so well and "BrendanB" who lent a hand drilling, tapping fitting etc.

As this was the first installation it took a little bit more time and we found better ways to do things but overall it looks pretty tidy and should go the distance.

To test it out a trip to little desert and big desert (VIC) has been organised for this coming weekend. This will give me the opportunity to air down and up regularly testing not only the air compressor but the advantages of running different pressures etc for different terrain. This would generally be avoided because of the time it takes just to air back up.

Here are the pictures for those interested.

Compressor next to A/C Unit.

https://www.aulro.com/afvb/images/imported/2010/05/878.jpg

It's a tight fit but there is still room to undo the A/C bolts if needed.

https://www.aulro.com/afvb/images/imported/2010/05/879.jpg

The air compressor is the same height as the A/C unit so as not to foul the bonnet lining.

https://www.aulro.com/afvb/images/imported/2010/05/880.jpg

The scissor bonnet stay has been straightened and folds down between the water reservoir (before anyone says replace it, I carry a spare one with me! And have a water alarm) and the air compressor guard.

https://www.aulro.com/afvb/images/imported/2010/05/881.jpg

New guards made up so that the bolts are held captive.

https://www.aulro.com/afvb/images/imported/2010/05/882.jpg

Top view of both compressors. Very neat in my opinion.

https://www.aulro.com/afvb/images/imported/2010/05/883.jpg

Another side on shot.

https://www.aulro.com/afvb/images/imported/2010/05/884.jpg

Air compressor air inlet.

https://www.aulro.com/afvb/images/imported/2010/05/885.jpg

Using standard tensioner with longer 4Pk belt. In the event the belt breaks you can bypass the air compressor and use standard belt. Of course carry a spare so you don't miss out on having continuous air.

https://www.aulro.com/afvb/images/imported/2010/05/886.jpg

Air from compressor coming into front of 15 litre tank. High pressure and high temp hose used! It also has a one way valve.

https://www.aulro.com/afvb/images/imported/2010/05/887.jpg

Tank is neatly tucked up under chassis. Outlets are for pressure switch and blow off valve.

https://www.aulro.com/afvb/images/imported/2010/05/888.jpg

This is the only part that has not been mounted to my satisfaction. I need a long length drill bit so for the moment this will have to do until I make it more permanent. On the other side of the pressure guage are the quick fit outlets.

https://www.aulro.com/afvb/images/imported/2010/05/889.jpg

This project has been in the back up my mind for ages so to finally have it installed and working is fantastic.

I will give a follow up report post the trip but feel free to make any comments or suggestions.

The intention is that the compressor, new bracket and belt will be made available from Steve (Madana) after testing. With possibly a full kit down the track.

Thanks again to Steve and Brendan for helping me fit it to my truck.

[B92 8NW]

Bloody hell that is so nicely built:eek:. I want one!




Good work:cool:.

[slug_burner]

Great looking job. I currently have a tank mounted like yours under the drivers seat. Currently using an electric compressor, it takes a little while longer and your upgrade is well executed, makes me want to give it a go.

What is the AC/Air compressor off? What is the part number for the longer belt?

[Madana]

The compressor is a generic swing type compressor, it is also a brand new unit as they are easier to source as brand new units. The drive belt is a modified 6pk belt as you are not able to get the same length belt in the 4PK version. I have set up 2 old compressors and made a trimming jig for the belt which trims them perfectly. My 300TDI disco has a hand modified belt which is running perfectly and has been doing so for the last 10,000+ Kms

[MinniTheMoocha]

Great looking job. I currently have a tank mounted like yours under the drivers seat. Currently using an electric compressor, it takes a little while longer and your upgrade is well executed, makes me want to give it a go.

You definitely could do it. The only really time consuming part is the engineering involved in the A/C mounting bracket. It's taken more than a few attempts fine tuning it. "Madana" (Steve) will be making it available after final testing.



What is the AC/Air compressor off? What is the part number for the longer belt?

I am not exactly sure but it is supposedly on some smaller European cars, and has come in from Asia. I think the belt is fitted to an Audi.

[MinniTheMoocha]

Bloody hell that is so nicely built:eek:. I want one!


Glad you like it.

Steve will be able to help you out!

[Disco_owner]

So how do we get hold of this newly designed A/C bracket ? :D and how much?

[roverrescue]

Very tidy.

What supports the base / back of the new compressor, the front gaurd bracket picks up one mounting bolt but have you extended the base plate off the Al front cover outwards to make a base for the new compressor? Are there any flexing issues?

One comment would be lose the scissor stay... I also thought I could bend around things (aircompressor, provent). On a rough road it will move sideways and then catch underneath the shiny new compressor and then you will have lotsa fun opening the bonnet! Trust me those scissors cause pain when they get stuck!

Just pull the thing off and either replace with struts (as seen on this site)
or be lazy and prop the bonnet with a piece of pipe when open.

Otherwise I like the look of it! I just pulled all the A/C junk out and wind down the windows. Once you have belt driven air you can never go back to 12V! What rating pressure are you running?

Steve

[MinniTheMoocha]

Very tidy.

What supports the base / back of the new compressor, the front gaurd bracket picks up one mounting bolt but have you extended the base plate off the Al front cover outwards to make a base for the new compressor? Are there any flexing issues?

One comment would be lose the scissor stay... I also thought I could bend around things (aircompressor, provent). On a rough road it will move sideways and then catch underneath the shiny new compressor and then you will have lotsa fun opening the bonnet! Trust me those scissors cause pain when they get stuck!

Just pull the thing off and either replace with struts (as seen on this site)
or be lazy and prop the bonnet with a piece of pipe when open.

Otherwise I like the look of it! I just pulled all the A/C junk out and wind down the windows. Once you have belt driven air you can never go back to 12V! What rating pressure are you running?

Steve

The new bracket includes mounts for the new air compressor. I don't expect there to be any flex as the mount is made out of 8mm plate steel, laser cut to shape. The air compressor is bolted using the base mounts.

The guard could be extended or include a lip to ensure the scissor stay can't get caught. Me preference is the straight bonnet stay from the front wheel mounted kit.

The pressure switch is a 110psi on 135psi off. I could run it at 150psi but I originally set it up for an electric pump. Will play it by ear for the moment.

[roverrescue]

Yeah I figured the new comp would be base plate mounted... I hope the 8mm is gussetted. There is a fair loaded pressure from the 4pk and if both compressors are engaged I can see a fair force applied to the mounts, plus 300tdi vibes!!!!

I have a 150psi switch but find the 4pk starts to slip just before it cuts out. Will be replacing the old compressor this week and will play around with pressures but Im thinking I will have to go back to a 135psi switch... one thing is for sure my old rattle gun boogies at near on 150psi!!!!

Regards,
S

[Madana]

Yeah I figured the new comp would be base plate mounted... I hope the 8mm is gussetted. There is a fair loaded pressure from the 4pk and if both compressors are engaged I can see a fair force applied to the mounts, plus 300tdi vibes!!!!

I have a 150psi switch but find the 4pk starts to slip just before it cuts out. Will be replacing the old compressor this week and will play around with pressures but Im thinking I will have to go back to a 135psi switch... one thing is for sure my old rattle gun boogies at near on 150psi!!!!

Regards,
S

Hi Steve,

Could you post a photo of you setup as I am curious with the belt slipping when reaching full pressure.
Under the bonnet of my disco I have run the 4PK belt very loose and had no slipage with the wrap setup. I have also ran the air comp with no support on top and was able to hold the compressor by hand.
I will fit the 150 PSI switch to my disco and see how it goes today

The builds are different to for the disco 300TDI as they run a Denso AC comp which fits on a cast alloy mount. this is removed and replaced by a new mount for the AC comp and the "Air Head" comp.
Defender 300TDI runs a sanden AC comp with a fabricated mount. This mount is replaced and new mount is used for Sanden AC comp and "Air Head" comp.
There is enough space between the bonnet stay and the "Air Head" when the bonnet is closed as the bonnet stay does not have enough movement sideways to hit the "Air Head" guard. This will be tested out further in the coming weekend.

[roverrescue]

I am using a standard Disco Denso compressor on the defender. So essentially it is the same as a stock 300tdi disco setup but is plumbed for air not A/C. I feed it air from the rocker cover - remote provent and have removed the factory cyclone.

I imagine with your twin comp setup you will get more belt pressure as the belt wraps the pulley more-so than a stock setup. Test out the 150 and see how it goes. I am replacing my Denso as the current one appears to have seized. I will pull it apart to try to diagnose the problem, Im guessing it will be lubrication related! Thinking about it a little, maybe the belt slip was actually the compressor starting to seize at higher head pressures (would look like belt slip). I only noticed the problem when I went up to a 150psi cutout? Previously ran it at ~120psi blowoff... And now the pump has seized completely.

Just giving you a heads up on the scissor stay, I too thought there was not enough sideways movement to impact in my case the provent your case the "Airhead"... it took me ages & lotsa skin to unstick the jammed up arm, 'tis only a small space between engine + junk and chassis rail. Just trying to save you grief ;)

Steve

[steveG]

Very nice bit of work. Love it!

Steve

[Madana]

I am using a standard Disco Denso compressor on the defender. So essentially it is the same as a stock 300tdi disco setup but is plumbed for air not A/C. I feed it air from the rocker cover - remote provent and have removed the factory cyclone.

I imagine with your twin comp setup you will get more belt pressure as the belt wraps the pulley more-so than a stock setup. Test out the 150 and see how it goes. I am replacing my Denso as the current one appears to have seized. I will pull it apart to try to diagnose the problem, Im guessing it will be lubrication related! Thinking about it a little, maybe the belt slip was actually the compressor starting to seize at higher head pressures (would look like belt slip). I only noticed the problem when I went up to a 150psi cutout? Previously ran it at ~120psi blowoff... And now the pump has seized completely.

Just giving you a heads up on the scissor stay, I too thought there was not enough sideways movement to impact in my case the provent your case the "Airhead"... it took me ages & lotsa skin to unstick the jammed up arm, 'tis only a small space between engine + junk and chassis rail. Just trying to save you grief ;)

Steve

Hi Steve,

Understand now your setup, the comp I am using has a much smaller footprint than the denso compressor. Also the compressor I am using overcomes the issue with the flex in the mounting plate as the mount is totally different to the denso setup.
I have physically checked again tonight and I cannot get the scissior stay to move accoss enough to conact with the compressor or guard. The guard on the compressor alos goes down far enough so it does not allow for the scissor arm to foul.
The fianl wiring was completed tonight and "Hour Run Timer installed"

[MinniTheMoocha]

Yeah I figured the new comp would be base plate mounted... I hope the 8mm is gussetted. There is a fair loaded pressure from the 4pk and if both compressors are engaged I can see a fair force applied to the mounts, plus 300tdi vibes!!!!

I have a 150psi switch but find the 4pk starts to slip just before it cuts out. Will be replacing the old compressor this week and will play around with pressures but Im thinking I will have to go back to a 135psi switch... one thing is for sure my old rattle gun boogies at near on 150psi!!!!

Regards,
S

I will test it with both compressor and A/C on and will put in a 150psi cut off switch to see if there is any slippage. I wouldn't expect it to but will hold off my verdict until then.

[Madana]

I have just changed over switches in the Disco with air comp and pressure guage is running to 170PSI before shutting air comp off. Had to do modifications to the blow off valve but it now holds the pressure. With the air compressor and air conditioner running at idle there was no belt slippage at all.

[roverrescue]

Well thats cool, so Im guessing my "slippage" was more to do with the failing DENSO unit as opposed to drive pulley pressure.

Sounds like your scissor has little play and may be okay, from memory mine was always a little slack (bolts flogged) but it was ages ago that I ditched it? If Im just checking oil / coolant I just hold the bonnet and if im doing any real work I pull the bonnet off.

Although its a rated pressure vessel and has blowoff valve I still get the jitters sitting on 22L at 150psi! But then if it was to let go - I guess I wouldnt be around to worry any longer?

S

[Madana]

Yes have to agree, just come back from shops and couldn't stop thinking about what I had just put into the tank under the floor.

[steveG]

Where did you source the tank from, and was there a reason you chose an aluminium one over steel?

steve

[MinniTheMoocha]

Where did you source the tank from, and was there a reason you chose an aluminium one over steel?

steve

The tank I fitted is from Boss air suspension (Used to be made in QLD but now in China somewhere)

I chose aluminium simply to save weight. A couple of ideas I had for tanks were out of steel or aluminium such as divers tanks but were really heavy and required a lot of work drilling / tapping holes etc. Have now started looking at other sources and there is a good selection air tanks that can be sourced. I just found that this tank was a good size to fit tucked up under the chassis and was in between the outriggers.

[slug_burner]

Got this baby from a truck wrecking yard $15, wire brush and killrust paint, wiring and plumbing not complete at this stage.

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

[MinniTheMoocha]

Got this baby from a truck wrecking yard $15, wire brush and killrust paint, wiring and plumbing not complete at this stage.


Looks pretty good. You obviously had to weld up the brackets though.

I don't have a truck wrecker anywhere near me :-(

[roverrescue]

My tank is a 22L jobbie from those supercheap compressors...
So it has three input/ouputs plus a drain at the bottom.
I bolted it to the floor of the DS sill and with an Al guard it sits just higher than chassis rail.

[MinniTheMoocha]

Well for the last week or so I feverishly worked on the finishing touches to prepare my rig for the desert trip.

All looked good but just as I was about to leave on Thursday night the engine shuddered, ran really rough so was turned off. It failed to start after that! Great timing......

So I had a choice of staying home and finding out what the problem was or going to the desert, I chose to go the desert. But meant I didn't get to drive or test the air compressor.

As soon as my car is running we will be taking a trip to Big desert again to be able to test it fully.

[MinniTheMoocha]

Well it's been a long time coming but I have finally got out on another decent 4WD trip so got to try out the the newly tweaked compressor.

The compressor is the same but Steve (Madana) got to improving lubrication and air flow.

I was happy with the Big Red air compressor I had but am absolutely rapped having this motor driven one.

The actual pump times will need to be recorded but I was done in about 4 minutes for all tires from 24PSI to 50PSI. The longest time taken is actually getting the hose out, walking around to each tyre undoing the valve etc.

Happy 4WD'ing
MtM

[ob1]

I installed my system today. It gets air from the air filter, to a Sanden SD 6 compressor. The compressor is fitted with a check valve, the pipe goes to the tank. Tank is about 30liter under the body and feeds a quick coupler at the diesel filler cap. The circuit activate from the cab with a switch and I fitted a pressure gauge, the gauge fed trough the firewall.

I am sure everything is air tight. Imagine the let down when I ran it for 10 minutes and about no air was in the tank. It was like an asthmatic mouse with emhysemia. I disconnected the pipe from the compressor and the flow is pathetic

The compressor is a 6cylinder Sanden working with a wobbly plate.
Any ideas?