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Onboard air - 200tdi 90 - A/C Compressor unit as Air Compressor...Its Great

Finally got all my bits'n'pieces gathered together this weekend to build my on-board air system on my 200tdi 90.

Bits used: A/C compressor off a 1990 Saab 900 Non-return valve Pressure switch 1025mm fan belt various iron plumbing fittings. A bit of wire to feed the clutch 12V via the pressure switch

I also had to fabricate two simple brackets, 1 to mount the compressor and one to mount the pressure switch and PCI connector.

Only other thing i had to do was have a new pully made to attached to the existing water pump pulley - this was the expensive bit (£50). The other alternative was to buy the LR crankshaft pully which has provision for 3 belts (mine only has room for 2) but this also means changing the fan.

Compressor is mounted where (I think) the standard LR A/C compressor would normally fit - sat on the timing belt case in line with the rocker cover.

New pully is fixed onto the long waterpump pully shaft and the bracket to hold the pressure switch and PCI connector is mounted off the clutch pedel housing cover plate.

The whole thing seems to work a treat - works no bother at 150psi.

The only thing i have overlooked is the lack of an oil filter in the system. Due to the compressor design there is some, but not much oil passed into the air and ultimately into tyres etc. A simple in line filter will cue this. Apparently York compressors get around this problem by having a dedicated oil sump but they are physically MUCH larger so will be heavier and much more difficult to accomodate in a

200tdi.

On the whole I think this is a great mod for any offroader, and not as hard as i thought it might be.

Phase 2 is to mount an air tank somewhere. I have aquired a CO2 tank from a pub, thinking of strapping it to a chassis rail somewhere and using that. Ideally i would use a small air-brake tank off a small truck.

Jon

Reply to
Jon
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Without oil the compressor is not lubricated and therefore will be ruined shortly. You need to use a oil-water separating device (don´t know the english term) so you have an oiled circuit for the compressor and clean air for your tires.

Raoul

Reply to
Raoul Donschachner

Reply to
Adam Swire

Cheap alternatives are used O2-flasks from divers.

Raoul

Reply to
Raoul Donschachner

Not sure about the Saab compressor but the York compressor found on many models has an oil sump to keep the piston well lubricated. This however does not preclude the system from passing oil through the lines. The oil/water separator IS the English term. I used an old fire extinguisher in my project. They are far more plentiful and hydrostat tested to over 500 lbs. Be sure to install a drain as these can rust from the inside out and explode if not drained regularly.

Have fun.

Reply to
Jack Kerouac

Really? Nice, that puts my to-be-built system in reachable dimensions!

;-) Ah, fine, thanks!

Fire extinguisher, good idea, would be even cheaper bought new than a used divers-bottle. Was there no possibility to rustproof the whole thing?

Raoul

Reply to
Raoul Donschachner

For a cheap solution use an empty freon jug from your local air-con specialist - I've used them for this on several vehicles. For a rust proof solution use a stainless steel fire extinguisher body.

Reply to
EMB

Are there any? How can I tell that one is stainless steel, if I remember correctly they are all painted red ;-)

Raoul

Reply to
Raoul Donschachner

There's plenty of stainless water type ones around and many are left as SS finish with labels attached.

Reply to
EMB

I'm thinking of doing the same on my Tdi300. I have sourced a dirt cheap V8 a/c compressor that's basically going for around a tenner. I know it still works fine because it was mounted on my friend's V8 rangy before he changed engine to a tdi300 due to fuel costs. So basically he just wants to get rid of it. I have no problem mounting the thing. My problem is that the pulley on the compressor is a v-belt (triangular cross section) pulley while the crankshaft pulley on my

300tdi accomodates the newer, thick flat belt (i think it's called a polyvee belt... it's got 3 or 4 grooves along the belt), and there is a provision for the a/c compressor's belt on it.

What are my options? Is is possible to change the pulley on the a/c compressor or do I have to find a rare crankshaft pulley with one polyvee and one pulley instead of 2 polyvees? Does anyone supply these pulleys or would I have to get one manufactured?

Sorry for all the questions. It's just that getting powerful onboard air for a few tenners (including pulley costs) sounds too tempting to me :)

Thanks for any reply.

Dennis

Reply to
Dennis

Firstly, many people will tell you not to bother because the compressor wont last long because it will cease up due to lack of lubrication. So what if it does, its cost you £10 for a compressor + a few airline fittings and a pulley. What you get when its working is FAR better than an electric one and MUCH cheaper than the "Endless Air" option that uses a Sanden A/C compressor anyway!!! If it ceases get another from another doner!

The way to avoid it ceasing up is simple:

  1. install an air filter in your airline. That way you can monitor how much oil it throws out (mine is very little).
  2. Mount the compressor so that the oil filler is easily accessible. that way you can simply put more oil in to keep it topped up.
  3. Put a switch in the cab in the 12V feed to the clutch so that it is not running all the time.
  4. I would advise putting a pressure switch into the system also. Mainly for safety, but additionally it means the compressor will keep starting and stopping as the pressure builds and drops.

As for the installation:-

I cant remember how the 300tdi connects the fan to the waterpump shaft. On the 200tdi there is a v-belt pulley linking the crankshaft pulley and then importantly about a 2 inch flange that is "doing nothing". I had a new pulley (6.5" DIA) fabricated onto this flange and then got a 1025mm long fan belt to connect the new pulley to the compressor.

So, I guess you may have 2 options:

  1. Get a new pully for the compressor - I think this will be expensive though because I think the electric clutch is part of the pulley! Then all you need is a longer belt to replace the existing.
  2. have a new v-belt profile pulley fabricated to an existing shaft and get a belt to fit between that and compressor.

Unfortunately I dont have a lathe so I had to pay £50 to get a new pulley turned up, heat shrunk onto the existing shaft and then dutch screwed to secure it.

If you decide to look at changing the pulley then Hella Climate Control can probably help you (01932 41 17 11).

Out of interest what model / make is the compressor?

Regards, Jon

Reply to
Jon

Yes I've had people tell me it will blow up due to lack of lubrication. However I'm not exactly sure if this thing has an oil sump or not (haven't looked at it closely yet). However I already had everything planned for the air filter to filter out the oil, and using a tool oiler to keep it relatively happy as far as lubrication in case it needs them. Also I'm not planning on using this thing everyday. Actually using it will be rather rare so if it ceases up after pumping up 50 tyres that would probably mean a good 5 years or so! Then, as you say, it only cost me a tenner and with some careful looking around I could get another one. It's more of a "if i don't do it now, I'll lose my chance of getting a perfectly good compressor for a tenner!". Who knows, maybe I'll eventually decide to use it for a/c.

I still need a pulley though. It sure is a pity that changing the compressor's pulley will work out to be expensive. My 300tdi uses a single serpentine polyvee belt (the thick belt with longitudinal grooves) to drive everything (power steering, water pump, fan, and alternator). The crankshaft pulley is actually 2 pulleys in 1. One drives everything as mentioned above and one is empty, presumably for fitting a 2nd polyvee belt to operate the a/c pump. That's why I was hoping to have the compressor's pulley changed, so as not to "waste" the currently unused pulley for this very purpose.

The compressor is off a 1983 V8 range rover classic. It's pretty big compared to the standard 300tdi compressor so I'll be fabricating a custom bracket to mount it. I don't have a lathe either so I'll probably have to fork out for the pulley like you did. Or else admit defeat and let it go to another friend who will have much less complications since he's got a 200tdi which uses v-belts :(. But then again, £10 for a compressor and £100 for a new compressor pulley still works out cheaper than £300 for a 300tdi compressor...

Decisions, decisions ....

Thanks a lot for the information though. Very much appreciated.

I'll report back when I get some prices :)

Regards, Dennis

Reply to
Dennis

Just out of pure speculative curiosity, how about getting a polyvee belt profile pulley fabricated onto the compressors current pulley and leave the v-profile pulley unused?. I'll have to mount the compressor a bit further back so it will align with the crank pulley but that's not a problem since I'm fabricating the mounting bracket for it anyway. And that way I can use my crank pulley's provision for the a/c belt.

It should work right? (please say yes :D)

Regards, Dennis

Reply to
Dennis

It should work but obviously it will need to remain clear of the clutch arrangement.

Assuming you get the pulley fabricated on top of the existing pulley the only downside I can see is that the new pulley will be larger than the original and therefore you are lowering the gearing, thus the compressor will turn slower and mean you need higher rev's to get the same amount of air.

FYI: Thats why I had my pulley made at 6.5" DIA so that I geared it up slightly - compressor pully is 5" DIA (high compressor rpm at tickover is what you need as you are unlikely to need high rpm on the move).

You could also add a resevoir to the system, then high(er) rpm will not be needed.

Good Luck. J

Reply to
Jon

Ahhh good to know it should work. I'll be asking some experts how is best to do it in the coming days. I already planned to have a reservoir in the system to help the compressor.

Certainly looking forward to this. If I can get that pulley sorted my problems will be over. Will be picking up the compressor on Saturday so I could examine it more closely because details are a bit sketchy at the moment.

I'll definitely be reporting back if I go ahead with it. Thanks for all the help Jon! Will let you know how it goes.

Reply to
Dennis

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