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Thread: Argon Engine Purge

  1. #1

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    Argon Engine Purge

    Testing the argon purge starts now. I'll pressure fill the Cessna's crankcase at the dipstick and will test for oxygen at the oil fill, the highest point on the engine. The question is how well it'll stay purged.

    Tomorrow I'll get a couple of tall jars and do a side-by-side rust test with some 4130 strap material, one with air and one with argon. I'm curious about this, so here goes.
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    www.SkupTech.com mike mcs repair's Avatar
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    Slow fill as to not “mix” with the air in there already.. ?


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  3. #3

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    I've wondered why not do this to airframe tubing during construction also? A good argon back-flow sure makes welding easier.. I've thought it might be good to just seal the tubes with argon inside.
    I think this engine idea is pretty cool. What would be the downside of nitrogen? I think it costs quite a bit less, and more people have a bottle for their oleos and/or tires.
    When welding, I always just held a lighter up to the outlet, and when the flame went out I figured it was ready.. but a sensor is way better.
    This is what I like about this site - I'll find your results interesting and appreciate your sharing.
    Jose

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    What I've already found? It's surprising how quickly the argon flows out the cylinders. I feel a little stupid for not anticipating that. And for that reason with a Lycoming's cam location nitrogen may be the answer. For testing I'll try pressure filling through the crankcase breather until oxygen is exhausted at the oil filler. If the induction and exhaust are the leak level the cam should still be purged. That's today's theory, anyway.
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    Would it help to rig some simple plugs for induction and exhaust? It'll be interesting to learn how long a purge lasts, once you've found an effective method to do it.
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    behindpropellers's Avatar
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    Quote Originally Posted by stewartb View Post
    What I've already found? It's surprising how quickly the argon flows out the cylinders. I feel a little stupid for not anticipating that. And for that reason with a Lycoming's cam location nitrogen may be the answer. For testing I'll try pressure filling through the crankcase breather until oxygen is exhausted at the oil filler. If the induction and exhaust are the leak level the cam should still be purged. That's today's theory, anyway.
    I wonder if this will put an air bubble in the oil pump?

    Tim

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    Put a balloon over the filler and partially inflate. This will let the temp swings occur without pumping moisture in, and tell you how long the purge lasted.
    What's a go-around?
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    That's an interesting idea but I'd need a zero resistance balloon since there's no way to maintain pressure in the case.

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    Try a Mylar Balloon taped to the exhaust pipe, on second thought there's no way to seal these engines , to many cracks in exhaust system, gaps in rings, valve stem allowances,
    gaskets leaking etc.
    the Best you can do is a purge every few days ? /weeks ?!/ months !/ years !!!!.
    Now if you covered the Prop and cowl with plastic and sealed the firewall you might have a chance of purging and the putting Argon inert gas , it might stay in place, You would still have to recharge at least once a month.
    Firewall would be a B@#ch as to the many holes and cracks.
    Hmmmm. OK I got it , the army makes a fiber box that they ship engines in which is gasketed and has a purge fitting for doing just what you want . You can find them at some of the Army/Navy stores or heavy machinery depos as they throw them away once in a while.

    Just remove engine when you want to pickle. Place in box , seal purge add nitrogen or argon , easy/ peasy as they say..
    Pick your poison and your time frame.

    Hmmm, come to think about it I need to pick up one of those boxes or make one out of fiberglass/
    That engine is not getting any younger hanging on the hoist.

  10. #10

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    If I'm concerned with stored engine cam corrosion? Cylinders leaking gas warrant a different recipe for Continentals and Lycomings. Lighter than air nitrogen should purge the cam of a Lycoming and heavier than air argon should do the same for a Continental. Once the gas is in place I don't expect it'll go anywhere unless the engine is rotated, but that's the purpose of the exercise, to test it. Not like I have lots of spare time but I enjoy these kinds of projects.
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  11. #11
    wireweinie's Avatar
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    I'm curious where the leaks, if any, will show up. While you won't be pressurizing the engine, I'd expect any heavier than air gas to stay put unless disturbed. I'd like to see how fast it might leak past rings, or out intake or exhaust systems.

    Web
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    Injecting argon into my Cessna engine was easy. In at the dipstick until the meter at the oil filler read to .02 oxygen. Stop the flow and the oxygen returned to normal air levels in about three seconds. Even with open valves that rate surprised me. My engine has very good static compression but that didn't slow the argon down. Nitrogen staying above cylinder level in a Lycoming will be interesting. How air-tight is an accessory case?

  13. #13

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    I just remembered something , or maybe not .
    You professional welders out there, there is one of the gases they fill the tanks up with sawdust then put the gas in it . this is because the gas is unstable in true liquid form in a voided tank. Is it Acetylene, or is it one of the other gasses . Also one of the gasses is dissolved into acetone in the bottle , just cannot remember which one it is.
    Nitrogen is not really lighter than air it is 78% of what we breath if I remember correctly.

    or does it it become lighter than air when it is not saturated with humidity? , Chemistry was a looooong time ago.

  14. #14
    www.SkupTech.com mike mcs repair's Avatar
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    Quote Originally Posted by Kahles56 View Post
    Also one of the gasses is dissolved into acetone in the bottle , just cannot remember which one it is.

    Acetylene

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    Mike, Thanks for the answer on Acetylene.

  16. #16

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    Mike, Thanks for the answer on Acetylene.

    On another question i am asking,
    has anyone, does anyone have a STC mod to drill through the crankcase to add piping to allow oil to hit the cam-lobes on a Lyc..

    I hate to use this term but here it goes, "Back in the day" there were some auto engines that had marginal oil delivery with cams, rocker arms etc. , racers , I include myself would drill into a pressurized oil galley and tap a fitting , plumb with .25 copper pipe and fish copper tubing to areas of need, solder up the ends of the pipe and take jetting drills and drill small holes to allow oil to spray where necessary . This saved many an engine.
    We also did the same thing to get rid of the oil on the head and externally piped oil drain lines to the pan as the return oil ports could not allow the oil to drain correctly (Fast enough) on added oil modified engines as well as non modified heads. Grinding of the head to get rid of cast iron flash and create valleys in the heads to allow flow back to the pan was the first thing we did and went from there. AMC 304-409 cu-ln engines as well as Buick engines come to mind. Man would those AMC engines produce power with very little work. Oil problems were there biggest draw back until we figured them out.

    One other thing guys, DO not do "donuts" in a motor that is not designed for racing , you will starve the oil pump after the second circle, you need a dry sump to do that kind of stunt. The oil will stay on the side of the pan opposite the turn, the pump will just pick up air on a regular oil pump system.

  17. #17
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    Quote Originally Posted by Kahles56 View Post
    On another question i am asking,
    has anyone, does anyone have a STC mod to drill through the crankcase to add piping to allow oil to hit the cam-lobes on a Lyc?
    Ney nozzles.
    https://www.aviatorshotline.com/content/chuck-ney
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  18. #18
    40m's Avatar
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    Can't help thinking about what adverse effects things like this might have. Seems like flying often resolves short term issues and preserving oil take care of the rest.

    "The interactions of five gases (helium, hydrogen, nitrogen, argon, and carbon dioxide) with mineral and synthetic lubricating oils were studied. The interactions examined included gas solubility, foaming, entrainment, evaporation of oil into gas, stability of oil in presence of gas, and effect of dissolved gas an oil viscosity. Several of the gases showed behavior (appreciably different from that of air) that was not predicted by conventional theories. No important differences were found between mineral and synthetic (diester) oils in these respects. The additives used can have appreciable influence on the foaming and entrainment characteristics, and evaporation rates, of both types of oils."
    Last edited by 40m; 09-17-2020 at 06:43 AM.

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  19. #19

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    The bigger idea here is that oxygen promotes oxidation. The idea is to displace oxygen. I'm not operating the engine in a argon or nitrogen environment. Ideally the presence of gas will be maintained while the engine is static. Whether it's maintainable is the question.

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