Dehydrator Spark Plugs

The place to raise issues, ask questions, swap ideas and discuss anything related to aircraft engineering, maintenance and building.
NB Any opinions expressed in this forum are not necessarily those of LAA Engineering

Moderators: John Dean, Moderator

Post Reply
ian herdis
Posts: 105
Joined: Tue Jan 08, 2008 3:45 pm

Dehydrator Spark Plugs

Post by ian herdis » Tue Jul 03, 2012 5:02 pm

Any one used the Dehydrator plugs for long term engine storage.

To re use the plugs you have to dry out the silica gel but the details on LAS and aircraft spruce state it takes 16 hours at 250 degrees. That seems like a huge amount of time?

Ian.
035374

Ian Melville
Posts: 1001
Joined: Mon Feb 11, 2008 7:21 pm

Re: Dehydrator Spark Plugs

Post by Ian Melville » Tue Jul 03, 2012 6:24 pm

Does seem like a long time, and the gas/elecy bill will suffer.

If they are the same as the Aircraft Spruce ones I think you can dismantle them and remove the Silica Gel. Then you can microwave (1 minute on High) the gel. The colour is the indication that they are devoid of water Blue = Dry

Heat guns(1hr) and halogen lamps also work
Ian Melville
032644

ian herdis
Posts: 105
Joined: Tue Jan 08, 2008 3:45 pm

Re: Dehydrator Spark Plugs

Post by ian herdis » Wed Jul 04, 2012 9:44 pm

Thanks, Ian

That seems more in line with what I expected, when I get them I will post the details

Ian.
035374

G.Dawes
Posts: 279
Joined: Wed Jan 02, 2008 11:00 am

Re: Dehydrator Spark Plugs

Post by G.Dawes » Wed Jul 04, 2012 10:22 pm

Yes that is what I do, they need to be out on a saucer and they will change colour very quickly, then get put back in the plugs

Bill McCarthy
Posts: 488
Joined: Mon Jan 07, 2008 4:06 pm
Location: Caithness

Re: Dehydrator Spark Plugs

Post by Bill McCarthy » Wed Jul 04, 2012 10:39 pm

If you are laying up your engine I'd have thought that you would be better off using fogging oil. Once your dehydrator plugs have absorbed to their limit you get no further protection - until you reactivate them.
032125

Ian Melville
Posts: 1001
Joined: Mon Feb 11, 2008 7:21 pm

Re: Dehydrator Spark Plugs

Post by Ian Melville » Thu Jul 05, 2012 6:58 am

No need to swear Bill :D

In addition to an oil change before layup, I would expect the use of preservation oil as well as the dehydrator plugs.
Plugs need to be changed quite often (15-20 days) especially this summer :cry:
Ian Melville
032644

ian herdis
Posts: 105
Joined: Tue Jan 08, 2008 3:45 pm

Re: Dehydrator Spark Plugs

Post by ian herdis » Thu Jul 05, 2012 4:36 pm

I was going to order the Tanis pickling kit which has the pugs and oil and other items required

But the procedure is to run the engine up to temp then change the oil/add an additive. However I am not sure if I will be able to run the engine as i am removing it from an aircraft which is being broken up for spares.

If I can not run the engine what is the best way to try and get all the engine coated in the preservative oil mix. Lycomings SB indicates spraying in the cylinders with a plug removed that seems ok but not sure how I could oil the rest of the engine.

Ian.
035374

ian herdis
Posts: 105
Joined: Tue Jan 08, 2008 3:45 pm

Re: Dehydrator Spark Plugs

Post by ian herdis » Thu Jul 05, 2012 5:19 pm

The Tanis kit is expensive and long delivery time. LAS has the plugs can anyone recommend a UK available preservation oil that I could use. Lyc 0-360

Thanks, Ian.
035374

Bill McCarthy
Posts: 488
Joined: Mon Jan 07, 2008 4:06 pm
Location: Caithness

Re: Dehydrator Spark Plugs

Post by Bill McCarthy » Fri Jul 06, 2012 9:19 am

Another thing I would do is to mount the engine in a proper stand and double bag it in polythene and place silica gel bags or activated alumina inside. In addition, it is very important to periodically turn the engine by hand.
032125

ian herdis
Posts: 105
Joined: Tue Jan 08, 2008 3:45 pm

Re: Dehydrator Spark Plugs

Post by ian herdis » Sat Jul 07, 2012 3:05 pm

Turning engine by hand------ I've had mixed advice about that some say turn some say not.

The lycoming preservation instructions say do NOT turn engine over the only time the lubrication system works is if the engine is running, when turning by hand all you do is scrape off the oil you deposited when you preserved the engine.

So I will preserve and not turn over, you should periodically spray the cylinder walls and dry out the dehydrator plugs

Ian.
035374

Rob Swain
Posts: 393
Joined: Tue Jan 08, 2008 2:11 pm

Re: Dehydrator Spark Plugs

Post by Rob Swain » Thu Jul 26, 2012 12:42 pm

Bill McCarthy wrote:In addition, it is very important to periodically turn the engine by hand.
Nooooooooooooooooooooooooooooooooooooooooooo!

Just scrapes the oil off the bores and leaves a nice clean steel surface to go rusty!
Rob Swain
If the good Lord had intended man to fly, He would have given him more money.

Bill McCarthy
Posts: 488
Joined: Mon Jan 07, 2008 4:06 pm
Location: Caithness

Re: Dehydrator Spark Plugs

Post by Bill McCarthy » Fri Jul 27, 2012 5:43 pm

I was told this when serving on RN frigates (many moons ago) - all moter launch engines which were in a fairly hostile marine environment hanging on ships' davits, had to be turned over. They had a hand operated stirrup pump to prime all lubrication points in the engines and the donks had to turned over by hand. When oil drains out of the bearings a corrosion cell can be established leading to rusty crankshafts - so they said. This was a weekly maintenance item as far as I can remember.
Anyway, if the aircraft engine was mine I'd get it on a good engine stand and invert the thing fairly regularly to get oil to the top of the crankshaft casing where condensation may take place.
032125

Post Reply