A bit over a year ago I completed a prolonged, expensive and at times excruciating rebuild of a Quincy reciprocating compressor (model 340-33) that had fallen victim to unseen water-accumulation in the crankcase oil. In this model (with no sight glass) condensed water builds up below the oil and might or might not show up on the dipstick until it's too late. It's not a nice, clean interface of water-to-oil, but rather a nasty globular rust-water-oil mix that's thick enough to dam up random areas on the bottom, so it won't even drain out by gravity. I just spent an hour or so with both side-covers off, swabbing out all the glop that I could reach.
Condensation is clearly a huge problem for me, but I'm not sure why. I'm in Honolulu, so it's usually fairly humid. But there's not much of a daily low-temp swing that (in my mind, anyway) would account for the internal condensation. I suppose it's possible the condensation is primarily in the top end, where it gets much hotter during compression, and trickles down through cylinders between cycles and overnight. Whatever is responsible, I ended up with well over a cup (maybe two or three - it's impossible to tell without decanting and even maybe centrifuging the glop to see what's water and what's oil).
This compressor is essentially hobby-use, so it's never going to get run as these are 'recommended' to run. But even if it were run daily, I don't see an exit path for condensation. The crankcase is sealed, other than an active extraction path (via an external 1/4" tube that ties into an intake above, in the head) - and it would be equally bad to have condensation trapped up there.
After about three hour-meter hours of run time, I found that the oil level was a bit HIGH (because of the glop accumulated below it) and this time, there was a telltale streak of brown glop on the dipstick.
Here I go again.
I'm thinking I will set up a small pump that would circulate the oil - and any accumulated water - through an external reservoir (ideally it would be a huge glass bowl with bottom-drain, so I could see at a glance whether there was drainable water, more glop, etc) and then back into the crankcase. If I could, I'd find a way to spray the returning oil up into the cylinders, to help wash down anything that might be accumulating up there. I already modified the sump with a bottom-drain port (vs the stock side-port) to maximize the drainage. I'm hoping that if this recirc system can be started up with new oil, the glop won't have a chance to accumulate on the bottom of the crank-case, and instead will be washed out into my new external separator system. I plan to time it such that it keeps circulating for X minutes after each compression cycle.
But you know, if there is an easier way, I'm all ears.
BTW, though I'm leery of taking lubricant shortcuts, the Quincy oil ("Quin-CIP," ISO100, SAE30) is painfully expensive and not even available here in larger-than-quart size, so I'd appreciate any lubricant-afficionado recommendations for good-but-cheap alternatives, at least for what I expect will be a flushing-out period before I replace it with the factory stuff. Synthetic oil is apparently a bad idea in this setting because it is somehow much more susceptible to water infiltration - so I think I can rule out any synthetic substitutions.
Ideas?
Thanks all - Dave
Condensation is clearly a huge problem for me, but I'm not sure why. I'm in Honolulu, so it's usually fairly humid. But there's not much of a daily low-temp swing that (in my mind, anyway) would account for the internal condensation. I suppose it's possible the condensation is primarily in the top end, where it gets much hotter during compression, and trickles down through cylinders between cycles and overnight. Whatever is responsible, I ended up with well over a cup (maybe two or three - it's impossible to tell without decanting and even maybe centrifuging the glop to see what's water and what's oil).
This compressor is essentially hobby-use, so it's never going to get run as these are 'recommended' to run. But even if it were run daily, I don't see an exit path for condensation. The crankcase is sealed, other than an active extraction path (via an external 1/4" tube that ties into an intake above, in the head) - and it would be equally bad to have condensation trapped up there.
After about three hour-meter hours of run time, I found that the oil level was a bit HIGH (because of the glop accumulated below it) and this time, there was a telltale streak of brown glop on the dipstick.
Here I go again.
I'm thinking I will set up a small pump that would circulate the oil - and any accumulated water - through an external reservoir (ideally it would be a huge glass bowl with bottom-drain, so I could see at a glance whether there was drainable water, more glop, etc) and then back into the crankcase. If I could, I'd find a way to spray the returning oil up into the cylinders, to help wash down anything that might be accumulating up there. I already modified the sump with a bottom-drain port (vs the stock side-port) to maximize the drainage. I'm hoping that if this recirc system can be started up with new oil, the glop won't have a chance to accumulate on the bottom of the crank-case, and instead will be washed out into my new external separator system. I plan to time it such that it keeps circulating for X minutes after each compression cycle.
But you know, if there is an easier way, I'm all ears.
BTW, though I'm leery of taking lubricant shortcuts, the Quincy oil ("Quin-CIP," ISO100, SAE30) is painfully expensive and not even available here in larger-than-quart size, so I'd appreciate any lubricant-afficionado recommendations for good-but-cheap alternatives, at least for what I expect will be a flushing-out period before I replace it with the factory stuff. Synthetic oil is apparently a bad idea in this setting because it is somehow much more susceptible to water infiltration - so I think I can rule out any synthetic substitutions.
Ideas?
Thanks all - Dave
