Thread: 300Tdi Motor Driven Air Compressor

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.



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



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



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.



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



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



Another side on shot.



Air compressor air inlet.



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.



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



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



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.



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.

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