VW Air Compressor

[dougefresh]

Has anyone ever built an air compressor out of a VW engine using a kit from Dunn-Right of S.C. They are selling a kit with a camshaft that converts 2 cylinders to pump air two cycle and the other 2 cylinders power the compressor.

Supposedly it puts out 58 CFM @ 100 psi. The cheapest kit costs $300.

[coad]

I'm curious about why you want one of these? Air compressors seem dirt cheap at Home Depot or Sears, and with the price of the kit and the value of the engine you're not looking at a real cheap solution compared to just buying one.

I'm not knocking you-- I just want to learn about these. Couldn't you score a vw industrial engine (or make the same kinda thing) and make it drive a regular compressor without all the two cycle modifications?

[TimGud]

Price a large compressor head and you will have your answer. If you want anything near 58 cfm,its big bucks. It has always sounded interesting to me but I have no need for anything bigger than about a 5 or 6 cfm.

[coad]

Oh, Question answered. I guess my brain didn't register the 58 cfm figure. That is indeed an impressive amount of air @ 100 psi. We're not inflating bicycle tires with that thing are we?

[dougefresh]

If your workspace is a residential area as mine is, you will be limited to single phase 240 VAC. About the biggest electric motor you will be able to get on this will be about 4HP tops. Home Depot had a compressor
they were advertising as 7 HP Peak, but when I ran the numbers based on the line amperage of the motor and the voltage, it actually worked out to about 3.5 HP.

If you can get 3 phase service from your electric utility, then you are in a different ball game. 3 ph motors are smaller
and cheaper than trying to get comparable power from single phase.

I want to do sandblasting, my 240VAC, 2 HP compressor I have now has difficulty running any air tool for more than a couple of minutes.

So yes, this project wont be cheap, you will need a vw engine(which I have) the cost of the kit, (300) and other parts not included to build the thing. I just wondered if anyone else had ever built one though.

Later,
Doug

[keifernet]

I would think that as long as they have been advertising them,( what like 15 years or more?) then they must be selling them and they must work pretty well
( if you know about VW engines and can keep one going)
so, even though I have never seen one seems like someone out there has built one or knows someone who has.
I'd be interested in the lowdown on one too.

[Air-Cooled Head]

I actually saw one of these mounted in the bed of a single cab service station truck. It was at a show so the guy wasn't running it, but he said it worked fine and delivered all the air he needed.
Doug, you make it sound interesting. But do you need 58 cfm for blasting? Most home blasters I've seen usually require 20 cfm or less. Check out
http://www.northerntool.com/webapp/wcs/stores/serv...yId=210532

[dougefresh]

AirCooledHead:
OK, I'm pretty sure I really don't need 58 CFM. But it seems a compressor more that about 15 CFM would cost me more than making one of these. And besides, imagine all the fun I could have building one. I'm willing to bet, I'd be the only one in the neighborhood with one.

I need to ask them a few questions, such as how does it auto unload when it reaches full pressure and how does the engine RPM come down at that point?

Will let you know what I find out.

Thanks for the feedback,

[Gary]

The more power the better. Also, the 'cheapies' are something I am wary of if it isn't ASME certified. That is the *big* clincher in my book. ASME - American Society of Mechanical Engineers.

[Grvlguy]

Guys, there is a VW shop in Rock Hill, SC called Bill's that has the VW compressor. His son runs a huge sand blaster on it and loves it. He has it on the small trailer. Not sure what the noise level is but when my small Sears unit comes on now you can hear it around the hood!!!

[Air-Cooled Head]

Doug. It does sound like fun. And I've got enough spare engine parts to do this. Maybe when I get done with the other dozen or so projects.....
By then, I prolly won't NEED a compressor.

[oorwullie]

i have one of these half'n'half compressors.never seen another one like it here in switzerland,although there's any amount of vw powered compressors and pumps around.anyone got any pics of these ones that are available in the us?
can i post pics on this forum?
forktruck is also flat4 aircooled!

[oorwullie]

obviously not......
try this link to picture.

[oorwullie]

hmmmm......
http://muchos.co.uk/members/oorwullie/forkcomp1.JPG

[oorwullie]

finally got it!

[MarkFV]

I have built my own compressor from a VW engine. It's not very hard.
The easiest version is to modify an intake manifold to run one side of the engine. The other side gets an air cleaner to filter the air. Remove the two spark plugs and connect a one way valve to each spark plug hole. I got mine from Graingers. Connect the two valves to your tank. Done.
This gets you about 110 PSI and 20 CFM.
Now this is 1/2 as efficient as the engine could be since the VW valve timing only gives you a compression stroke every other cycle.
The kit that Dunn Right makes uses a modified cam to use the VW valve train as the air valve.

I choose to go further without the Dunn Right kit. I replaced the left head with a flat aluminum plate 1" thick. I don't use the push rods or VW valve train for air. You must block the push rod tube holes.
I then drilled 2 holes into each "cylinder head/plate"and installed a one way valve into all 4 holes. Note on each cylinder one valve is pointing in, one valve is pointing out. This gets you air on each revolution. The flat plate gets your compression ratio up to 10 to 1 so you get 150 psi max not 105 with a 7 to 1 ratio. Connect the two "ins" to an air cleaner, connect the two outs to a tank. You can use the output of the compressor directly without a tank. I used to for sandblasting. One thing you need to do. The air comming out is quite hot due to the compression. A rubber hose will cook in 10 minutes! I ran it through copper tubing in a coil to cool the air. A water bath will help. The tank helps cool the air and is a thermal radiator itself.
Works quite well and you don't have to take the VW block apart. I used an old 1300 engine. When I bought the valves 10 years ago they cost $15@. 300 PSI working pressure and 1" diameter. I just set the carb arm to run at 2800 RPM. Loaded or unloaded was only 2-300 rpm different. The engine has much more HP than the compressor side needs.
Mark

[dougefresh]

Mark:
I like this method. I looked in the Graingers catalog and found this:
http://www.grainger.com/Grainger/wwg/catalog/viewCatalogPDF.jsp?CatPage=2621

Described as Inline Check Valves,"Specifically designed for air compressor discharge piping. Valves open at less than 3 psi with maximum hold back pressure of 450 psi." 1/2 in FNPT, 400 deg.F. $15.00 ea. page 2621

Let me know if this is the right valves. I think I could do the rest of it.

Thanks
Doug H.

[MarkFV]

They look very similar to the ones I used. I used the 3/4" $22. but that's probably overkill. The ones I have say 400 PSIG working pressure which is still more than enough. I chose to use the #3-4 side of the engine as the air compressor since the oil cooler is on that side and #1-2 runs cooler. The carb will run rich on just 2 cylinders and right over the port. Use J tubes for the exhaust if you need to route it outside. A pair of lawn mower mufflers (10 HP) on cylinders #1 and #2 works well, if you are in open air and won't get gassed out..
Mark

[CleanThatPoolTile]

1967 VW Air Compressor Conversion ... 'Lucky Lime' ... Dunn Right Inc. ... Cleaning Pool Tile, in Tucson, Arizona.

https://youtu.be/ytiAQqEzgCQ

Cleaning pool tile, in Tucson, Arizona, since 2014. Compressor makes 56 cfm @ 100 psi. 'Volks-Aire' conversion kit from Dunn-Right Inc. The magic is in the cam shaft: 4 cycle, in the front, two cycle, in the back.

[sandhopper]

I have one of the dunn right compressors . I need to do a tune up , How do I adjust the valves for the air cylinder ? Mine shuts the engine down when it gets to 100 lbs in the tank , how do I keep it running ?