Dose anyone have suggestions for rebuilding the Air Venturi compressor. looks like the high pressure rings are gone.
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Air Venturi 4500psi Compressor
- Thread starter jmel81
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Have you done a rebuild, if so is it worth the effort, I hate to just toss this compressor.
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Yeah I did it lots of times. I'm parting mine out because the motor blew and the crank case broke but I got about 5 or 6 years out of it before that. I changed the high pressure rings about 2 times per year. I got to where I could do it in about 15 min
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What I would do is remove both metal lines and the thermometer from the high pressure head. You don't have to remove the water lines or drain the system if you are careful. Then remove the 4 bolts that connect the high pressure head to the black piston cylinder. If you're careful when removing it you shouldn't damage the gasket. Slide the head off of the high pressure rod. Remove the old rings and any pieces of them that fell into the lower piston. Use some needle nose pliers to stretch the new rings, carefully turning them around as you stretch them. Stretch only a little at a time and evenly, and only enough to get them over the rod. Once you have all three on, use two small hose clamps to tighten them onto the rod, be careful not to pinch the rings, make sure they're flush inside the slots. Wait about 5 min or so, then remove the clamps. I use my finger to rub some of the compressor oil ( I used air venturi's) onto the rod and at the entrance on the head. Then carefully slide the head back on and put everything back together and you should be back in business unless there's a different problem like one of your metal valves went
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IdK if there's a better place but I got mine here. Bad news is they're stupid expensive and you need 3. They're sold in packs of 1 because reasons and stuff
www.pyramydair.com
AV 4500 Compressor High Pressure Piston Rod Seal | Pyramyd AIR
We've got a great price on AV 4500 Compressor High Pressure Piston Rod Seal at Pyramyd AIR. Shop where the experts do!
www.pyramydair.com Upvote 0
Seeing as you have had some hands on experience with the AV compressorIdK if there's a better place but I got mine here. Bad news is they're stupid expensive and you need 3. They're sold in packs of 1 because reasons and stuff
AV 4500 Compressor High Pressure Piston Rod Seal | Pyramyd AIR
We've got a great price on AV 4500 Compressor High Pressure Piston Rod Seal at Pyramyd AIR. Shop where the experts do!
There is a lot of black oil coming from the bleeder is this a sign that there is another problem or is
that what happens when the HP rings burn out
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No mine always discharged a bit of water mixed with the compressor oil when bleeding. I only ever used the air venturi compressor oil
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Ok thanks, looks like these AV compressors have a lot of problems, and they are not cheap, I guess it's time to dissemble it.
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It would be nice if someone can post of finding the correct AV one piece rings for the AV compressor on Aliexpress for a reasonable price. Paying $9 apiece for the 3 rings required is price gouging IMHO. Pyramyd sells a 2 piece white delrin piston ring tool that makes the installation much easier. The first part is cone shaped piece that allows the ring to be gradually stretched. Do not stretch the ring completely over the cone shaped delrin piece. Stretch it enough to fit over the piston but not completely over the cone or it becomes overly stretched. Once the ring is over it's piston groove use the other part of the tool to slide over the ring and compress it into its groove. The tool costs $12 at last check and it's well worth the convenience it provides. It is always easier to install new rings from the top groove down rather than bottom groove upward.
My last bit of advice is to not substitute Tuxing brand split piston rings on an AV piston. They don't fit the AV piston precisely and don't seal. I got some from another forum member and they looked perfect when installed but they won't seal. Tuxing rings are in abundance on Aliexpress. I've had no luck finding AV rings but others are welcome to share if they found them online for less than $9 apiece.
My last bit of advice is to not substitute Tuxing brand split piston rings on an AV piston. They don't fit the AV piston precisely and don't seal. I got some from another forum member and they looked perfect when installed but they won't seal. Tuxing rings are in abundance on Aliexpress. I've had no luck finding AV rings but others are welcome to share if they found them online for less than $9 apiece.
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It's totally price gouging. Absurd. I forgot about the tool's existence, but if you make sure not to pinch them, the hose clamps do the job. I didn't know it stretched them too though. That is probably a better way than using pliers.
I tried the split rings you mentioned. I got some but never concluded whether they worked or not.
I put them on and it wouldn't compress. I threw them away and just got the AV ones. When I put those on, it still wouldn't compress. It turned out one of the metal valve flap pieces had broken, and that was the problem. So I'll never know for sure if they would've worked or not but if they're anything like the ones you mentioned, I'll bet they wouldn't have.
I was tired of the AV's crap and so when mine broke big time, I bought a cs4. It's better in every so far way in my opinion, except it doesn't fill as fast. It goes to higher pressures though. It's less than half the price of the AV. I have not used it much though, so longevity and reliability, I can't yet speak to.
In the air venturi's possible defense, when I took it apart, I noticed one of the mounting bolts and nuts that mounted the motor to the frame was very loose, and it was on the front side of the motor. I don't know how long that bolt was loose but I think it's possible that it contributed to the motors failure. Can't be sure though. Wouldn't hurt to periodically check those to make sure they're tight.
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Asher, the flap piece you referred to is a check valve. They get dirty and don't seal when burnt oil residue clogs them up. If one breaks it would stop compression at a certain pressure. AV replacement rings need to be warmed by working them with your fingers in order to soften them before stretching them. You can use any cone shaped object to stretch them a bit so they can be installed over the piston. I'd recommend a closed pair of needle nosed pliers. The delrin 2 piece installation tool from Pyramyd works the best but it costs $12. I've never owned an AV but I repaired one for a local air gun buddy.
It is critical for any high pressure compressor to use dedicated purpose compressor oil. The oil sold for lubricating low pressure compressors are not worth the savings as they burn and create sludge under high pressure. Don't buy Harbor Freight, Lowe's, or Home Depot oils that are made for ship compressors that only go up to 125 psi. Conversely, it is a total overkill to buy Mobil Rarus oil at $20 for 12 ounces to use in a Chinese compressor. $20 a quart Secolube 500 from Filtertechs works just as well at a third of the cost. It's like buying jet fuel for a go kart.
It is critical for any high pressure compressor to use dedicated purpose compressor oil. The oil sold for lubricating low pressure compressors are not worth the savings as they burn and create sludge under high pressure. Don't buy Harbor Freight, Lowe's, or Home Depot oils that are made for ship compressors that only go up to 125 psi. Conversely, it is a total overkill to buy Mobil Rarus oil at $20 for 12 ounces to use in a Chinese compressor. $20 a quart Secolube 500 from Filtertechs works just as well at a third of the cost. It's like buying jet fuel for a go kart.
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Hello Asher
Turn's out I had added to much oil (over the red dot) so oil got up into the HP Piston. That may have burned out the HP Rings I will need to pull the head and check
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I have the Hatsan version of the same compressor. Gotta love them, they replaced the first one I got. Then they quit supporting them all together. I ordered a bunch of parts from Ali Express. 2 rebuilds in 4 years. It just crapped out again. Not sure if I will rebuild it again or just junk it.
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