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Author Topic: OS Exterior Tarnishing  (Read 432 times)

Online Dave Moritz

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OS Exterior Tarnishing
« on: January 09, 2019, 12:47:43 PM »
Howdy All:

The motor is a new, inherited OS 46LA and my first. It has a Gardner P/L and Randy setup. The few, careful break-in runs I put on it before cold weather hit gave me some tarnish. I like pretty engines, but also like to know that they are running strong without self destructing. Is this a concern or something I should just live with?

Dave Mo...


Offline Gerald Arana

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Re: OS Exterior Tarnishing
« Reply #1 on: January 09, 2019, 04:20:58 PM »
Howdy All:

The motor is a new, inherited OS 46LA and my first. It has a Gardner P/L and Randy setup. The few, careful break-in runs I put on it before cold weather hit gave me some tarnish. I like pretty engines, but also like to know that they are running strong without self destructing. Is this a concern or something I should just live with?

Dave Mo...


How about a picture?

Thank you, Jerry

Online Dave Moritz

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Re: OS Exterior Tarnishing
« Reply #2 on: January 09, 2019, 06:45:17 PM »
Take a gander ar this. Thanks.

Dave Mo...


Online Dave Hull

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Re: OS Exterior Tarnishing
« Reply #3 on: January 09, 2019, 07:57:36 PM »
You got that in just a few "careful" runs???

It looks like baked on castor. If so, it will come off no problem when properly cleaned. But why are you getting so much fuel/oil on the outside of the engine? If you aren't using the muffler pressure nipple, I'd cap it--but that isn't where all of this is coming from.

Dave

Online Brett Buck

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Re: OS Exterior Tarnishing
« Reply #4 on: January 09, 2019, 09:35:02 PM »
Take a gander ar this. Thanks.

   Holy Crap! That's some serious varnishing for just a few runs. I note that it is all on the "lee" side of the cylinder (and you can tell it was on the ground). That will clean easily with a crock-pot, if you want to disassemble it, but where does all the oil come from?  I have 20FPs I have been running on and off since 1995, and they don't look as bad as this. The solution is to stop the oil coming out, if possible, it's either:

the front end (fixable with an oil return groove, probably, or heavily worn and fixable with a replacement case)
leak around muffler mounting - face off flat (with 220 wet/dry on a steel or glass plate), and then add a gasket of some type. I would use header gasket sealant
blow-back from the intake, either running it too slowly or someone altered the shaft timing, might be avoidable with an air filter to intercept the fuel mist.
some other leak

    Brett

« Last Edit: January 10, 2019, 09:58:22 AM by Brett Buck »

Offline Bootlegger

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Re: OS Exterior Tarnishing
« Reply #5 on: January 10, 2019, 10:02:38 AM »

  My question is how much castor is in the fuel?  It appears to be all castor, maybe some synthetic oil in it also..
  Good luck, and please share with us when you find the reason..
8th Air Force Veteran
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Online Dave Moritz

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Re: OS Exterior Tarnishing
« Reply #6 on: January 10, 2019, 10:25:55 AM »
This place really rocks!

Dave: It's set up to use muffler pressure, so no open fitting there. So methinks it's Brett to the rescue again!

Likely no problem with the front end (pending inspection). I have direct evidence that one of the owners (yours truly) was running this mill too slowly ("carefully"). I also have empirical evidence it has no muffler gasket.

So, here's the plan. Disassemble and give the antifreeze treatment to the block and muffler. Smoothen the muffler mating surfaces. Install a gasket. Finally, tac the thing out when running, shooting for something between 11,500 and 12,000 on the APC 11x5 prop.

Brett: You suggest header gasket sealant. What kind of material is that (a flat sheet of gasket material, goop in a tube, etc.)? Where's it found?

Legger of the Boot: Good point. On the last couple of bench runs, I used Brodak 5% nitro, 11.5% synthetic / 11.5% castor. But then much of the tarnish was already present from other unknown fuels.

I'll report back when all is said an done. Not sure what conclusion will emerge with my multi-pronged approach, though.

Thanks to you all..

Dave Mo...

Online Dane Martin

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Re: OS Exterior Tarnishing
« Reply #7 on: January 10, 2019, 10:50:09 AM »
I mentioned on a fb post (I know, the devil) that I don't run castor in my os engines. I run 15%n 18%syn oil on my 40-46 and 20%n 18%syn oil in my 25's. Now, OS company recommends 18% oil.  In one manual I read, it says they recommend 4% of that to be castor, as a cushion to the plain bearing.
Castor alone didn't do that to your engine. Brett hit that on the head. I guess I'm just commenting to comment. And because I think Dave is one of the coolest dudes ever.

Online Brett Buck

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Re: OS Exterior Tarnishing
« Reply #8 on: January 10, 2019, 11:26:13 AM »
Brett: You suggest header gasket sealant. What kind of material is that (a flat sheet of gasket material, goop in a tube, etc.)? Where's it found?

   Almost any regular gasket material would work - it doesn't get all that hot. OS sells gaskets that I think are conventional paper - I haven't seen one in a long time. It needs some sort of goo, or it will get pushed out by the pressure.


 But I would use the stuff I already have:

https://www.amazon.com/Permatex-81878-Copper-Silicone-Gasket/dp/B01LZ7WZAT/ref=asc_df_B01LZ7WZAT/?tag=bingshoppinga-20&linkCode=df0&hvadid={creative}&hvpos={adposition}&hvnetw=o&hvrand={random}&hvpone=&hvptwo=&hvqmt=e&hvdev=c&hvdvcmdl={devicemodel}&hvlocint=&hvlocphy=&hvtargid=pla-4584001418790449&psc=1

   This is the best thing for pipe header gaskets, so it ought to be overkill on your muffler. Just a tiny bit will do, and it tends to get everywhere (very sticky and hard to clean off). It probably says to clean it, make the joint just "snug", wait overnight, and then tighten it fully. If you have time, that probably works, but I have cleaned/faced off the surfaces, wiped the with lacquer thinner, applied, tightened up hard, and flew the airplane 10 minutes later.

   Sealant might not be necessary, if you get it flat. I have been using *nothing* on my 20FPs and the like, straight from the factory finish, and they seem to seal up very well with nothing. I wouldn't trust it with a tuned pipe because even a tiny leak is unacceptable, but for a muffler it seems to be fine.

      Brett

Online Dave Moritz

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Re: OS Exterior Tarnishing
« Reply #9 on: January 11, 2019, 10:45:08 AM »
Thanks for the info, Brett - you never disappoint!

And Dane, lest there be any mistake in identity here, I too think that Dave (Hull) is one of the coolest dudes ever.

Dave Mo...


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