Centrifugal Oil Cleaning?

[BillL]

I read a link Walt provided that mentioned that lead in the oil plates in valve guides. Lead suspension is also an issue that prevents use of full synthetic lubes. (although not the only reason)

My career experience is in diesel engines where there is suspension of particulates (soot) in the oils. For the longest life, through management of oil properties, many engines use glacier/spinner II centrifugal separators to settle out the particles. These little guys are no larger than our oil filter canisters and have a 3/32" oil office that spins to yield over 4000 g's. At least for our side engine. Elimination of these carbon particles drastically reduces wear. Imagine a sand slurry, or abrasive water jet, it is much the same.

http://www.spinnerii.com/files/comm_...SalesSheet.pdf

Well, we know that the CS prop & crank nose will do the same thing and many older cars and motorcycles used crank mounted separators back when lead was still in all fuels.

So - has anyone ever used this type of treatment for our little Lycs?

[Neal@F14]

A very long time ago, my family had a 1970 Fiat 850 Spyder. The engine was only equipped with a centrifugal oil "filter" built into the crankshaft pulley assembly. The oil pressure started getting really low and when my dad disassembled the centrifugal filter to clean it out, it was completely jam-packed full of gray putty-like sludge. Later we learned that the sludge was basically pure lead particulates and ash that has gotten into the oil from running leaded gasoline, and the "filter" was nearly 100% clogged, causing oil starvation to the rest of the engine. Based on this experience, such a centrifugal oil cleaner if run on an aircraft engine that burns leaded fuel, must be cleaned out on a very regular basis or it would suffer the same fate.

That poor old Fiat eventually spun a rod bearing, likely as a result of the oil starvation caused by the clogged centrifugal filter.

[BillL]

Yes, Neal, Fiat was one that had that slinger in the end of the crank, Honda bikes had them too. I rebuild a lot of those Fiats in the early 70's. I think the high temps of the south and interstates were more than those engines were validated for. I learned a lot about engines from the failures encountered. I saw the same stuff plated out in crank oil passages and lightening holes too.

Here is a specific centrifugal unit under consideration.

http://www.spinnerii.com/files/comm_id_30/25.pdf

It uses .8-.9 GPM of engine oil. Do some engine guys know if there is that much available at 2200-2700 RPM? Note I have an IO360 M1B.

It would have to be mounted high with a generous drainage back to the crankcase.

[SHIPCHIEF]

We use those Glacier units at work also. They do clean out a lot of carbon from the oil.
An idea: Weight is always foremost on my mind, so I would suggest the centrifuge be mounted on a cart. After flying, with the oil still warm and particles still in suspension, attach the hoses to the engine and run the oil thru the centrifuge for a timed iterval.
Disconnect before flight.
As a side note; The bottom of the sump on a Lycoming is a gravity sludge trap. My son Peter recently installed a Raven inverted oil system on his RV-4.
This requires the removal and modification of the sump. There was a generous amount of sludge in the bottom, which caused us to look into the issue.
Some feel these engines should have the sump removed and cleaned periodically.
Disclaimer: I don't have a filter on my Lycoming, so I change the oil @ 25 hours or less.

[Mike S]

Originally Posted by SHIPCHIEF

The bottom of the sump on a Lycoming is a gravity sludge trap. My son Peter recently installed a Raven inverted oil system on his RV-4.
This requires the removal and modification of the sump. There was a generous amount of sludge in the bottom,

Back in the era when these engines were a fresh design, it was common that they used non-detergent oil, and no filter. The oil pickup was spaced above the bottom of the sump just to allow the crud to settle out. Old cars did the same thing.

I had an old 1964 Honda with the centrifugal filter, worked well.

[cajunwings]

Lycomings have a centrifugal separator of sorts. Most engines with some hrs on them will have a buildup of lead/carbon sludge in the bore of the hollow cranks.




Don B

RV 9 Rebuild in Progress

[SHIPCHIEF]

O-290s and O-435s have sludge tubes in the hollow crank throws, there is a special Lycoming tool to remove them during overhaul.

[WenEng]

From the hollow crank? When I un-taped the end on my 800 hour stored engine to get ready to mount prop I was surprised to see a buildup and didn't know what it was. How can I get it out without worrying about doing any damage?

[Bubblehead]

Be aware that according to the brochure they need to be nearly vertical to work properly. One of the data sheets said it needed 60 to 80 psi to work which should be OK at cruise.

[DanH]

Originally Posted by BillL

It uses .8-.9 GPM of engine oil. Do some engine guys know if there is that much available at 2200-2700 RPM? Note I have an IO360 M1B.

Oil flow is claimed to 7 gallons per minute. I've never heard an RPM with that spec.