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OBA for$100 (Warning - long post)

cbbr

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We must have looked at 400 vehicles before we found what we were looking for – a York A/C compressor. It was in a 1970's Ford F-100. It did not have an identification plate, but the York is immediately recognizable. Check it out -

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We cut the v-belts and spun the compressor. It spun free. Next we cut the hoses as far from the compressor as possible and spun the compressor while pushing the clutch in. Suction was good.


We removed the compressor and the stock brackets just in case we needed those (again, more on those later). We took the compressor and some assorted junk that we couldn't live without to the front and hooked the compressor to a battery that they have for testing purposes. With the negative from the batter connected to the body of the York, we touched the positive to the battery and the clutch engaged.


$24.95 (plus tax) later and the York was in the back of the Suburban. I paid another $10 for the factory bracket which was a waste of money.


I had moved the washer fluid container forward in hopes of installing on board air and a tank. That in mind, we were working on an install on the driver's side. We took a section of 90-degree angle steel and "fabricated" a bracket. Truth is that we cut it, drilled holes in it and trimmed it with a grinder until it fit on two studs coming from the block at the manifold. We then took a piece of flat bar, bent it to 90 degrees and attached it to the side of the York and to the top drivers side bracket bolt holding the alternator. Looks like this -

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Next came the pulley. I have basic welding skills (basic is being kind) and a MIG, so we intended on using the idler pulley from the bracket that I bought as the drive pulley for the York. Specifically, the pan was to weld the alternator pulley and the idler pulley together so that the York would be driven off of the alternator.

About a hour later we were off to AutoZone where I learned two things - 1) you cant just buy an alternator pulley if you screw yours up and 2) the idler pulley that we had just destroyed trying to remove it with a BFH was $15.

These facts made us reconsider my original plan. A call to www.OnBoardAir.com was in order. I spoke with the folks at OBA who were very helpful and a few days later the pulley was at my doorstep. I costs $40 and was well worth it. I also ordered a dipstick from OBA for $5, which seemed like a good idea.

The OBA pulley (I got the underdrive model) works great. I measured the belt length with a piece of string and got a v-belt from AutoZone (just go around the counter and try them out), hooked it up and now have OBA.

Next was how to harness the OBA and make it more useful.

I had a cheap, broken 6 ½ gallon home compressor in the pile on the carport which fit the bill. It was intact, but didn't work. I took off the engine, we cut off the handle and wheels (being careful to stay off of the tank with the cutting wheel) and the tank fit perfectly in the area left after moving the washer tank. The tank -
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Wiring was simple. Fused hot wire from the battery to the pressure switch and fused hot wire from the pressure switch to the lead on the York (25 amp each). The tanks pressure switch also has a two position switch for when the compressor neds to be totally off. The York grounds to the Suburban and only has one wire, so its hard to mess this up.

As for plumbing the system, that's where the stock hoses came in handy. $20 worth of "fix-it" kit and couplings later and the system was plumed. I used the stock outlet hose to make a short compressor hose, used an extension and connected it directly to the tank. See -

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For the inlet, I attached a silencer from a lawnmower (costs $3 at Home Depot) into the stock hose with a "fix-it" kit that is for hot water heater hose ($5 at Home Depot). See -
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I attached the tank with two ratchet straps (costs $10) that are bolted to the inner fender well. I used a piece of insulation to keep the bolts from gouging the tank. See-

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After testing the switch and trying a few combinations, the tanks pressure switch operated the York's clutch perfectly. I set the switch to turn the York on at 75 lbs and off at 125. There are two safety valves - the original on the tank and another that I attached to the tank at the inlet using a 4 way connactor from Harbor Frieght.

The quick connect from the tank is zip-tied to the grill and I put a waterproof switch in the grill so I don't have to raise the hood to use the OBA.

Tools run off of it with no problem and it should be great for airing up. All for about $100 and one day of “work”.

 
Awesome write up!! :thumb:
Looks like Im going to be junkyard hunting to do this aswell

How big of an air tank is that?? I know its 6.5 gal but like deminsions?
 
You done good!
Thought out and executed really well.

Well written article too!
 
The Datsue 240Z's came with the same York compressor with a nice bracket. I have the AC off of my 1972 240z and might see if it will fit on the Blazer this weekend.
 
Thanks. The tank is 21" long and 9" in diameter. Fits perfectly if you move the winshield washer tank up to the front.
 
Looks good. Personally, I'd go for one of a Volvo. They're easy to find, long stroke, and have a good bracket to work with and get patterns from.

I should take some pictures of my setup at some point.
 
Great job on the write up... and thank you! This is my next mod.. and before i even had to start searching around.. poof! theres all i need to know. :cool1:
 
We actually looked for one from a Volvo, but had no luck. I found one in a Mercedes, but it did not spin freely. The one that I got does not have an ID plate, but it fills tha tank to 125 psi in under 20 seconds at 2000 RPM so it will get the job done.


Just for fun we hooked an impact wrench to it and ran it wide open continously with no problem with the engine at a little over 2000 rpm starting with a full tank.
 
Great write up!


Can you tell us a little more about the pully you had to purchase? Got any close up pics?

Thanks!


cbbr said:
We actually looked for one from a Volvo, but had no luck. I found one in a Mercedes, but it did not spin freely. The one that I got does not have an ID plate, but it fills tha tank to 125 psi in under 20 seconds at 2000 RPM so it will get the job done.


Just for fun we hooked an impact wrench to it and ran it wide open continously with no problem with the engine at a little over 2000 rpm starting with a full tank.
 
I would like to see the pulley you have as well(Part number would be cool as well)
 
Pulley is P/N 061-007 1.9"/2.75" K6 Overdrive Combo Pulley $40.00 found at www.onboardair.com Look under Engine Driven Kits. Doubles up the 6 groove serpentine on my engine with a v-belt. I measuresd the v-belt size with a piece of string wrapped around the pulley and the York pulley with the York mounted. I took the pulley and string to the parts store to find the proper belt. - This is the picture from the site -

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They were very helpful and the pulley is very well made.
 
How do you adjust the tension on the v-belt? Do you have any more pics of the mount and where it mounts? Thanks I am trying to do this on a sepentine system as well. One more what are the specs on the piece of angle? Just 2x2x1/4" Just wondering about how that peice will hold up because the york is pretty heavy. Maybe some gusseting?
 
I bought the v-belt after mounting the York. Drill the L brace on the side that mounts to the Alternnator mount after you mount the belt and it helps brace the york and provides tension.

I didn't gusset the angle steel (2x2x1/4 is correct) b/c I can't imagine it breaking before the bolts and the L brace helps support it. Probably not a bad idea and I may actually do it just to make sure. The belt also puts a fair degree of tension on the York and it all feels very solid as mounted.

The angle piece is mounted to two studs below and behind the alternator. I'll see if I can find any pice that show them.
 
cbbr said:
I bought the v-belt after mounting the York. Drill the L brace on the side that mounts to the Alternnator mount after you mount the belt and it helps brace the york and provides tension.

I didn't gusset the angle steel (2x2x1/4 is correct) b/c I can't imagine it breaking before the bolts and the L brace helps support it. Probably not a bad idea and I may actually do it just to make sure. The belt also puts a fair degree of tension on the York and it all feels very solid as mounted.

The angle piece is mounted to two studs below and behind the alternator. I'll see if I can find any pice that show them.

I have had this saved in my favorites. Just wanted to bump it to see how your bracket was holding up. I am going to finally start on this project. Good post for all the new guys to see too. :D
 
i can not remember the name of that compressor, but its not a york. same design and it will work fine. ford had a version of it for a while. i saw a TON of them at the junk yard i used to work at.

any toughts of an oil seperator ?
Grant
 
sure its a "york"???

I'm not that familiar with A/C compessor "brands"....but to me that looks more like a "Tecumseh" compressor,or maybe a "Bendix".:confused: .most of the Tecumseh ones I saw and sold at the junkyard were 2 cylinder ones,Chrysler products used them mostly..

Guess it doesn't really matter anyway!..great write up,and it works good,thats all that really counts!...I love reading posts like theese,beeing somewhat of a "mad scientist" myself..:p: :bow:
 
very cool....theyre in a lot of cars here in san jose(junkyards)... i got lucky..my dad had an old volvo. well it crapped out on him and he sold it to the junk yard. it had the big stroke compressor in it so i yanked it right before:D .. oh yea snaged the mini turbo and intercooler hahaha:haha: :haha: .
 
How has that method of mounting the tank been working so far?
I am trying to figure out the cheapest / best way to mount my tank.
 

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