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Inhibiting after Engine Run on test truck

TASEsq

TASEsq

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I got asked how I wanted the engine inhibited after the runs were done on the test truck. The runs will be done with aero shell 100 (red band).

Having read over Lycoming service letter 180b specifically:
“An alternative method is the use of Cortec VC1-326 preservative concentrate added to the original oil at a ratio of 1 part VC1-326 to 10 parts of oil.”

I assume they mean this additive. (The name is slightly different).

This is vastly cheaper than the original method in the lycoming letter (corrosion additive mixed with aeroshell 100 oil / nox rust). Aka the Tanis kit.

I was wondering if the additive was fine to add to the break in oil? The service letter doesn’t specify the type of oil.

I would then mix some extra up and spray it into the cylinders also (it calls for 2oz per cylinder, or about 60ml). Can you even spray aeroshell 100? (Maybe it needs to be hot to spray?)

Then desiccant bags in the 2 exhaust pipes and one in the throttle body, plus desiccant plugs.

Do the desiccant bags need to be the fancy ones from spruce, or Amazon is the same thing?
 
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Lots of ways and people have strong opinions.

Not a debate but an option for you. Used bulk desiccant from ACS that can be regenerated. I wouldn’t be too concerned about using some bulk material from Amazon. A quick, easy home test would prove its value. Capacity isn’t as important as its ability to indicate.

No moisture = no catalyst for oxidation.

VAF forum link
 
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A couple of old time engine mechanics around here said they add 2 cans of STP to the oil & spin the engine up with the starter to distribute it & spray some in the cylinders.
Probably poo poo’d as a process for a $80k engine these days.
 
The logs for our 270 hour TTSN and 20 Since teardown and inspection for a prop strike IO-540 say that the engine was preserved using the Lycoming Serivce Bulletin about 25 years ago. When we replaced all the rubber seals before installation, we drained the oil, shot some marine preservative oil in the cylinders (everything borescoped clean) and it fired on the first blade, starting right up like it had never been asleep. Just a data point for you.
 
I have a newly overhauled IO-540 that came with a rv10 kit I purchased. It’ll be years before I need it. I fogged the cylinders using marine fogging aerosol, pulled the mags and fuel pump and capped( going w SDS system eventually) , plugged the front of the crank and filled the engine w new motor oil. I can say a 540 takes btw 11-12 gallons to completely fill.
 
So chatting to the shop and they have a big drum of the MIL-C-6529C Type I concentrate - according to the lycoming letter this gets mixed with mineral engine oil (aeroshell 100) at a ratio of 1:3.

That bit is fine - we can mix that into a batch of oil once the test running is done, and run it up to temp on that oil mixture.

The lycoming letter then says to spray 2oz of the “preservative oil mixture” into each cylinder. This is presumably what we have mixed above?

However, the Tanis kit (which they say is lycoming approved) sprays the cylinder with “nox rust” - or “One 8 oz bottle w/sprayer of MIL-P-46002”

So the first step is fine, I’m happy with that, but wondering what the lycoming recommended stuff is for spraying of the cylinders? I note that the “MIL-P-46002” is the recommended spec in the continental service letter for spraying the cylinders (and the cortex vcpi -326 seems to comply with this according to the spruce website anyway).

If I have to buy the cortec stuff, am I better just using this mixed with the normal oil as well? (This is permitted by the lycoming letter).

Or are there other products complying with MIL-P-46002? Searching for “marine fogging oil” brings up a bunch of products but none I can find mention a spec.
 
None of the fogging oil products will carry a specific spec if they are consumer grade products. You can't be sure as to what oil is actually being "fogged"," besides that it is some type of aerosolized oil.

Cortec VPCi-326 is the real stuff. How an oil like this works is that it is not just an oil that inhibits by adhering to metal surfaces, it is actually a vapor phase corrosion inhibitor.

Non-AD oils work by literally just staying adhered to the metal surface and preventing moisture access by this coverage.

The vapor phase corrosion inhibitors do more than that and continually release a solvent bearing vapor which displaces moisture and prevents corrosion even if not immersed or completely covered. Imagine almost like "zone" corrosion inhibition instead of just by direct coverage.

The reason Lycoming says to add the Cortec 326 and then run it, is that getting it up to temp maximizes release of vapor inhibitor as the engine cools down. This is better for protecting the cam which cannot be immersed. The cam CAN be immersed it just takes a TON of oil to fill up the crankcase in its entirety!

I would fog the cylinder with an oil like 326 then use desiccant at any opening. I had an engine sit for awhile and had no issues with this approach.
 
mic2377 said:
The cam CAN be immersed it just takes a TON of oil to fill up the crankcase in its entirety!
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You can put it on a rotisserie and rotate it from time to time. My engine sat for years - I just filled it with gallons of oil, sealed the intake and exhaust, swapped out plastic desiccant spark plugs from time to time. It was in a garage without heating or cooling, so it saw some humidity. No rust that I could find, but I of course could not inspect the cams. Not really sure exactly how it was preserved before Mattituck shipped it to me - perhaps they used Cortec VPCi-326 - only @mahlon_r would know!
 
My limited understanding is the Core tech product is used for engines that have been running and will be down for an extended period of time. Not for a new engine just out of the test cell.
 
JonJay said:
My limited understanding is the Core tech product is used for engines that have been running and will be down for an extended period of time. Not for a new engine just out of the test cell.
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What would be the difference?
 
JonJay said:
The Coretech mixture isn’t recommended as a lubricant. The procedure for use wouldn’t lend itself well to the initial test stand run in.
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We would run it on mineral oil. This involves an oil change after an hour or so. Then at the end, we would add the product to the existing oil and run it up to temp as per the lycoming SI. Then fog the cylinders - trying to work out what to use for that.
 
When we ran engines in the test cell after overhaul or repair we used 3 parts straight mineral oil to one part engine preservative that had some MIl-spec that I can't remember the numbers of. Then after the run we high pressure sprayed that mIl spec preservative into each cylinder and the engine breather. rotated the engine and re sprayed and then installed the desiccant plugs. It was a home brew of aeroshell fluid 2F, that isn't available anymore if memory serves me. It was approved to be run in the engines for something like 25 hours during its life time. It could also be used in the field for long term preservation of an engine that was going to sit for a while. You drained the oil and then installed the mixture and flew the aircraft for like 1/2 hour and then retuned to base and sprayed the cylinders. Installed desiccant plugs. The process we used was approved by the FAA and both TCM and Lycoming as a Process Spec for the repair station as it varied a bit from what was listed in their respective repair documentation.. Good Luck, Mahlon
 
mahlon_r said:
When we ran engines in the test cell after overhaul or repair we used 3 parts straight mineral oil to one part engine preservative that had some MIl-spec that I can't remember the numbers of. Then after the run we high pressure sprayed that mIl spec preservative into each cylinder and the engine breather. rotated the engine and re sprayed and then installed the desiccant plugs. It was a home brew of aeroshell fluid 2F, that isn't available anymore if memory serves me. It was approved to be run in the engines for something like 25 hours during its life time. It could also be used in the field for long term preservation of an engine that was going to sit for a while. You drained the oil and then installed the mixture and flew the aircraft for like 1/2 hour and then retuned to base and sprayed the cylinders. Installed desiccant plugs. The process we used was approved by the FAA and both TCM and Lycoming as a Process Spec for the repair station as it varied a bit from what was listed in their respective repair documentation.. Good Luck, Mahlon
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Thank you.

That sounds straight out of the lycoming SI. If my understanding is right, the MIL-C-6529c standard they mention is an aeroshell product called 2Xn. When mixed with oil 1:3 it makes aeroshell 2F.
 
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