GTA
Support Equipment For PCP/HPA/CO2 and springers ,rams => Support Equipment For PCP/HPA/CO2 => Topic started by: cosmic on August 18, 2018, 07:57:34 PM
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Well, all was well until 4000 psi.. The sound changed and I walked over to it and was looking at it then Bang (&^^& my pants, parts flying.) !!Anyone got parts?? Piston was a few feet away and head units were next to it...
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What gun was this?
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That was what is left of my compressor.. Topping up my scba tank...
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Sorry to see this and I'm glad you weren't hurt but... I can see this happening more and more if we keep filling tanks to 4k and above with these compressors. I would absolutely stick to filling guns directly to 3k if I had one.
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Did your tank bleed all back or did you get it shut off?
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Couple questions. Was the oil level high in the crank case? How long was it running time wise when it let go?
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Just change the royal purple so oil was fine .. It was shut down at no more than 55c and allowed to cool to 20C.. Total runtime on the unit, about 50 minutes.. First time to try for 4500 psi.. The correct order of start up and shut down was always followed.. This was supposed to be a 6000 psi compressor.. No luck for me..
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Sorry to see this and I'm glad you weren't hurt but... I can see this happening more and more if we keep filling tanks to 4k and above with these compressors. I would absolutely stick to filling guns directly to 3k if I had one.
That's exactly the conclusion I'm drawing about my YH compressor. I think it's asking a lot for these compressors to fill any kind of tanks especially when you get to that 4500 limit.
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sounds like a high pressure leak into the low pressure cylinder .. not combustion..unless that's impossible?
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sounds like a high pressure leak into the low pressure cylinder
If that is possible, it could sure cause this kind of failure, IMO....
Bob
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I seriously doubt its a high side leak, I have two of these and when theres and issue its always the high side piston failing but what I have seen online and looking at how its built is a main bearing failure or rod failure. My guess is it was a rod failure. Because you heard a change in the machine while running Id bet the crank either waked away from the main bearing or the rod was bending then broke. These compressors are underbuilt and Id bet they were vacuum pumps or refrigeration pumps that have been converted I seriously doubt they started their lives as HP pcp pumps.
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I agree with Travis rod failure at the wrist pin but the connecting rod to crankshaft still intact,, Also possible bad cylinder casting..
I just don't have the bucks to repair it.. Hoping to find some parts cheap or free... Only me !!
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Be cheaper to buy another one
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Travis do you think y'all will be able to get the 3 stage SPA, these small compressor's aren't really cut out for filling tanks IMO. I can see doing a little at a time but extended sessions is probably what's killing them. If I ever get one of these small compressors I probably wouldn't use it for filling tanks, just guns directly.
here's a REAL compressor
(https://farm1.staticflickr.com/892/42068967235_422e86f3eb_c.jpg)
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Holy @$%^. I think I might pick up some dye penetrate and developer and examine my parts for signs of damage. I've done a full tear down of my YH head and Vevor head (just like this one that came apart), and while the castings were rough, they didn't appear bad but this has definitely got me spooked. Although I have spare parts, I'm not really looking to sell them off. If you wind up pulling some money together, I'm happy to help you find replacements on AliExpress though.
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Hmmm concerning, as this looks like the same unit I have. Seems to me it was a bad cylinder casting, as a rod type failure typically has heavy scoring in the sides of the piston. Judging from the pictures, I don't see scoring, although the pics are rather blurry.
Also seems the bolts should go through the head to the case, although I question if the case would hold the torque required to keep it in place. Bad design?
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Also possible bad cylinder casting..
Sure looks that way to me. The bottom of the cylinder is still bolted to the case.
I am glad you are OK!
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Thanks I'm good after washing my shorts !!! By the way, I changed out to the barbed fittings after chasing leak after leak.. Here is some better pics..
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Looks like a bad casting on the connecting rod or the low side cylinder.. Minimum I would need is a cylinder, low pressure piston, and connecting rod… Taking measurements now..
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piston bore about 42 mm, connecting rod from crank hole to wrist pin 73 mm , bottom of connecting rod 20mm ,wrist pin 12mm..
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Is the chunk of connecting rod still on the wrist pin seized / gaulded to the pin or merely put in place to show the catastrophic failure?
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No just enough of it to hold on the wrist pin..
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I think that is the failure point and the piston slamming into the head blew out the jug.... (Cylinder)
Wow... you really coulda died there.
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Tell ya what....
I have the MRodair Airmax Extreme MKII. It's a dual piston like the AV. I've been filling my 3300 psi scuba tanks with it. Maybe 4 fills since service. I have a SCBA 30 minute 4500 tank coming next week. I think I'll do a service on mine before I make my first 4500 psi fill. Oil and filter changes. Then I run slow with rest stops for the first time. I've never had an issue as of yet but I feel the need to be cautious.
P.S, PPE will be in play.
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I think Travis is right, wrist pin end connecting rod failure.... The HP piston (which is rigidly connected to the LP piston, right? ) kept the LP piston straight in the bore and prevented much galling.... The broken rod probably drove the LP piston into the end of the cylinder, pushing it out the top by breaking the bottom of the cylinder.... My guess, anyways....
Bob
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Travis do you think y'all will be able to get the 3 stage SPA, these small compressor's aren't really cut out for filling tanks IMO. I can see doing a little at a time but extended sessions is probably what's killing them. If I ever get one of these small compressors I probably wouldn't use it for filling tanks, just guns directly.
here's a REAL compressor
(https://farm1.staticflickr.com/892/42068967235_422e86f3eb_c.jpg)
Yes were working on the details
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Just simple physics, you double the load of the original design and expect it to last?
All of these pumps are build on a regular one or two cylinder shop compressor frame, designed to run max 10bar. And then added a new head with extra piston.
Now you have two work loads on the same crank and rod designed for the single piston at 10bar and have 10bar x piston area plus 300bar x small piston area! And you wonder why it blew up?
Marko
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Just simple physics, you double the load of the original design and expect it to last?
All of these pumps are build on a regular one or two cylinder shop compressor frame, designed to run max 10bar. And then added a new head with extra piston.
Now you have two work loads on the same crank and rod designed for the single piston at 10bar and have 10bar x piston area plus 300bar x small piston area! And you wonder why it blew up?
Marko
lots of them out there....they should all be blowing up by now
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I'll stick to filling gun cylinders only to 3k with the small compressor-they seem to work well for that but could still fail. I think I'll be making a scattershield to put over the compressor when running as well. As rws_53 notes, the actual failure rate may not be that high considering how many are in use and the number of failures that have been reported but any such failure could easily cause injury. I'm now thinking I'll plan to buy a Daystate or Airetex compressor since they seem to have much more robust engineering and seemingly should last a lifetime for air gun use.
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Just simple physics, you double the load of the original design and expect it to last?
All of these pumps are build on a regular one or two cylinder shop compressor frame, designed to run max 10bar. And then added a new head with extra piston.
Now you have two work loads on the same crank and rod designed for the single piston at 10bar and have 10bar x piston area plus 300bar x small piston area! And you wonder why it blew up?
Marko
lots of them out there....they should all be blowing up by now
More time passes and more will fail, but what do I know, I'm just an engineering student with over 25 years of work experience in mechanics and prototyping.
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Personally, I think the small compressors are working at the edge of the envelope for filling 4.5k tanks. Hopefully, 3k gun fills will not be as much of a problem. It will not be that difficult to make a metal box with vent slats to sit over the compressor-this would allow air flow but should contain any flying debris from any failure. I have a local fire station that fills my GW tank at this time but will be purchasing a more stoutly engineered compressor for tank fills in the future.
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3k gun fills will not be as much of a problem.
That is what I am banking my money on... and 3000psi paint ball 48ci bottles.
If it holds up to those I am happy.
:P
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Same here. But I'm still making a metal cover.