I've never been a big fan of electric compressors, generally, they are slow, draw lots of current, can be unreliable and just never really seem to do the job very well.
Having had an engine powered compressor on my Gwagen for years, I was pretty keen to have a similar setup on Piggles, but it is pretty unusual to run that kind of thing on a 660.... well, it's pretty unusual to run a 660.... but I digress
I had the air conditioning compressor and bracketry from Greg's old cappuccino conversion lying around, and it bolted onto my 660, and I'm running a 1.0 sierra fanbelt to power it. The compressor is a small vane unit, shared, I have discovered, with Mitusbishi lancers, baleno's and I think various other small japanese cars.
There are three types of air conditioning compressor - Piston, Axial piston, and Vane. Piston compressors -, generally made by York, have been used on V8 Falcons, volvo's, old Mercs and probably many others. These have a sump and are very reliable, but they are very heavy and bulky. They're not really suitable for mounting on a 1.3, let alone a 660. The deliver around the 9 cfm mark. Thermally, they don't seem to heat the compressed air excessively.
Axial piston compressors (Some denso, Sanden(?) Endless air) require oiling or modifications to work long term reliably. Endless air sell several styles of Denso compressor modified with different seals and a grease nipple. Some of these are quite compact and can be mounted in a 1.3 sierra, although there are no off the shelf bracket kits for them. Axial piston compressors seem to deliver 8-9 cfm. The outlet air can get VERY hot with this style of compressor. I think the Denso compressor standard on 1.3 sierras is an axial piston compressor.
Vane compressors are quite common and may be the poorest candidates for an OBA application. They are very compact, but have very large internal seal surfaces and rely heavlily on their oil supply for sealing. Oiling the supply air is critical for these compressors. They do deliver adequate air (I think mine's doing maybe 6 cfm) that's way beyond what a readily available electric compressor can deliver. Mine seems to run pretty cool. They "leak down" between their pressure side and inlet side when idle, I believe this is a by-product of the internal channels used to direct oil back into the suction side to endure oiling is maintained. Running one of these out of oil would see it fail almost instantly from what I can see. Output varies enormously with revs, not something I noticed with the York. At idle, the compressor delivers next to nothing, but at 3000 rpm or so, it's pretty quick.
I have set mine up with a tool oiler on the suction side, but it doesn't seem to be working. I don't think there is enough flow/pressure to make the venturi work in a suction application. I will review this. ATM, I have dumped a heap of oil into hthe compressor, and as discussed on outers by Mightymouse, these vane compressors don't seem to discharge much oil into the compressed air which is surprising considering the amount of oil in it.
I'm running an ARB pressure switch and a relay to run the system, and a filter regulator in the engine bay. When complete, there will be a large tank under the tray and the filter/reg will be after that. I have some leaks to sort and the hosing needs a tidy up once the location of all the components is confirmed, but at this stage I'm pretty happy.
I'll get round to posting some photos once the layout is sorted.
Steve.
