Thread: 300Tdi Motor Driven Air Compressor

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

Very nice bit of work. Love it!

Steve

Originally Posted by 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

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"

Originally Posted by 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

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.

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.

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

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.

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

steve