DAVV compressor froze up !!!!

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I used the high dollar Coltri oil. Oil on dip stick right now, looks like brand new. I've noticed a few times in the past, where it seemed to come to a rather abrupt stop when turning off, whether with pressure, or not. I'm suspecting some type of lubrication failure inside. Always wondered about the lubrication system, and how they kept oil out of the bottom (4th stage) cylinder, as it sits face down on the bottom of the crankcase. I'll get more into it, if my arthritis allows. Gettin old ain't for sissy's 😅

https://www.nuvair.com/oil-coltri.html
 
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Generally compressors are shipped absent of OIL needing to have crank case refilled with the appropriate compressor grade lubricating oil prior to use. Not accusing, just stating a possibility if unknown and sadly happened ?
Click to expand...


My Coltri MCH6 arrived with oil and about one hour of run time on the meter. They also included an extra quart of compressor oil as the manufacturer recommends a change after five hours use and then every 50 hours after that. 50 hours is about 10 years of use for me.

If the compressor in question is a Coltri MCH6 clone, the Coltri MCH6 manuals might help some:

https://www.nuvair.com/manuals/MCH6_user.pdf

https://www.nuvair.com/manuals/MCH6_parts.pdf
 
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OK, got the side plate off, and I can't see anything wrong. Still stiff to turn, but doesn't look like any of the 4 cylinders is causing the problem. Next I'm going to take off all the lines, and see if it wants to turn over any easier. Beginning to think that somehow, oil seeped into the bottom (high) pressure cylinder, and is causing the lockup. For the life of me, I can't imagine how the oil is supposed to stay out of that cylinder, with it being on the bottom, and in constant oil from the crankcase. Also noticed this 4 cylinder model is being dropped everywhere, and only the 3 cylinder available. For instance the Daystate compressors. I have an overhaul kit, includes all the gaskets, and all the piston rings, reed valves etc. but NO "O" rings at all, and this kit has a double set for the second stage, but none for the third stage, so I ordered another kit, only $30 shipped.

https://www.amazon.com/gp/product/B07Z5TBZM1?ref=ppx_pt2_dt_b_prod_image
 
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I own a LC-110 and it's setup like this, the 3rd stage is indeed at the very bottom.

Untitled.1601910603.png

 
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Yes, I've babied this compressor ever since I bought it 14 months ago, 12 month warranty Ha! Always run for a couple minutes before I close the valves, and a couple minutes after finish filling, and bled out. It feels as if some of the cylinders have oil in them. Don't know how? Too much oil ??? If/when I reassemble, I'll fill with a measuring cup to the preferred amount, instead of going by the dip stick. More to come. Going to have to remove the compressor from the frame, to get the bottom (high) pressure check valve out and see if it's got oil in it. Then will proceed to cylinder 3, 2 and 1. Fingers crossed there is no metal damage.😉
 
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OK, turns out, it was the 4th stage piston, froze up in it's cylinder. Finally got it apart, and after trying some 800 grit paper in the sleeve (cylinder) I had to go to some fine valve lapping compound. Finally got it to where the piston (just a steel rod) would slide freely in the sleeve. Put it all back together, and only getting up to around 1200 psi. Might be some leaks to check, there are so many lines I had to take off. Or else it's just the 4th stage is shot. Don't know what caused the problem, but was almost as if the sleeve (cylinder) had went egg shaped! ???? NOT low on oil, always run an extra fan on the compressor when it's running. Run it a few minutes with the drain valves open before I start to fill a tank, and run it a few minutes after too. More later, if I find the problem. Next step may be to see if I can buy a 4th stage from DAVV, but I really dread tearing this thing all back apart again!😆
 
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Congrats -- I like mine -- and I'm just a fellow hobbiest.

In all the research I've done it's a Coltri MCH-3 LC (Low Consumption) EM (Electric Motor) minus the spiffy breathable air filter, cause you know, airguns care about breathing quality air or something, LOL.

Manual attached in case it helps. 330mL oil fill, remove the crack case nut so that it doesn't vapor lock, change the oil every 10-20 hours depending on duty cycle (oil is cheaper than a new compressor), 2 minute run before filling, cool down (depending on runtime and ambient temperature) and woot.

Undersize the load, oversize the compressor, and let the compressor work for you instead of you working it.

:) :)

download.png
View attachment MCH-3.1602632881.pdf


 
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Scotchmo, if there were a link, that showed prices etc. I might have went with a Coltri, but their web pages leave a lot to be desired. You have any links, and I do not like making deals over the phone. Yup, the Daystate I ordered, is a Coltri MCH-3, and has some pretty good reviews, so we'll see. At 71, I'm getting too old to be futzing around with these things. I just want to be able to top off my 2 tanks at 4500psi. I also have an Arytek booster that I use to top my rifles off, after my tanks get below 4500psi, to limit the amount of running time on my compressor. But I usually top off my tanks at around 3000psi.😃
 
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You usually have to call Nuvair to get current prices. I called yesterday and was told it’s still $2500 for the MCH6 in airgun configuration.

If you want a compressor for use with a standard 110v outlet, the LC110 is a good choice. From Nuvair, a properly configured 110v MCH3 costs about the same as a properly configured MCH6, so the LC110 is a better deal in that case.
 
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Knowledge is power... Maybe safest to only fill tanks to 3200psi since it may be subject to failing at any time with repeated over 4000psi fills If I read correctly it's only a stripped down scuba 3260psi (relief valve) fill unit thats pushed beyond its original design limits. Your Chinese one seems to be superior to this MCH3 which appears to only be a 3 stage whereas your Chinese MCH6 Clone is a superior 4 stage.

Be mindful regardless of warranty you are still subject to pay shipping and insurance to send it back whenever you need to if it's beyond your means of repair expertise..

If they totally redesigned it and you bought something new and totally different then the Daystate LC110 that were sold up until this summer only a few months ago then please disregard all of this irrelevant hogwash below.

https://www.airgunnation.com/topic/daystate-lc-110-fail/



https://www.airgunnation.com/topic/daystate-110v-air-comp/



https://www.airgunnation.com/topic/daystate-110-compressor-stalling-out/



https://www.airgunnation.com/topic/daystate-lc-110-dead-at-1195-minutes/



https://www.airgunnation.com/topic/pcp-compressors-and-shipping/



https://www.airgunnation.com/topic/yuck-rust-something-else/


 
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