Shelf Life of Engine Spares - ???

[Wotname]

What is the shelf life of common engine spares?

Things like fuel & oil filters, belts, impellers, gaskets etc. Sure it will depend a little on the storage conditions and packaging, but what is you guesstimate?

Of course one doesn't know how long they might have been on the distribution shelf before purchase!

My 2GM20 engine is 12 years old, has been in service for almost 6 years and has 280 hours on the clock.

I have two spare sea water pump impellers, one is 12 years old and the other 2.5 years. Both in original packing but of course, I no longer know which is the older one :bang head:. I am cautious about using either except in an emergency.

I am also cautious of using the spare air filter (which is 12 years old). Given the engine mounted air filter just disintergrated when I removed it today, I thinking the spare would also be as fragile.

So a new impeller and air filter is on the shopping list.

I am thinking the 12 year old belts will be reasonably safe to use if required as the original belts in service are still quite good.

The fuel filters (in original packing) should be fine - I assume!!!!

My spare oil filters are never more than 12 months oil as that is my replacement schedule and the spare gets fitted and replaced with a new one.

Your thoughts…

[Sandero]

Long...

[Dockhead]

Just rotate them as you do regular maintenance. Simples. Impellers, filters, belts, and hoses are really no problem.


More difficult are things like starters. These should be stored carefully, preferably in vacuum sealed bags with dessicant.


Don't do what I did -- buy a spare without verifying that it actually fits. I carried a spare starter for years, and at the moment when I needed it, it turned out to be the wrong part

[El Pinguino]

Anything involving rubber has a limited life... maybe 20 years... I think I have already spoken about my FW circ pump on a Volvo MD17D.... original failed at about 20 years ... engine had been out of production for 20 years... so all replacements probably 20yo.

'New' ones ... 2 sourced in Chile, one in Finland , one in UK , one( maybe 2 ) in Oz ... all from Volvo dealers) all failed either out of the box or within 50 hours... they have a rubber bellows thingo. ( all changed under warranty)
Ended up having a 'new' one rebuilt in a local pump shop at Volvo dealers expense.

Same same with lift pumps.... I carry 2 spare.... one spare currently due for rebuild.

[skipmac]

Originally Posted by Dockhead

Don't do what I did -- buy a spare without verifying that it actually fits. I carried a spare starter for years, and at the moment when I needed it, it turned out to be the wrong part

Yes. Had the same problem. Put together a full box of spare belts, impellers and such from my local shop (who I knew well and had done business with for years) before I took off cruising. Raw water impellor blew down island and when I pulled the spare it was the wrong part.

Called the shop and they were very apologetic and sent a guy straight to the airport to same day ship a spare (Delta Dash is a great service if you need something NOW!!!) which took me a week to get but that's another story.

[El Pinguino]

BTW... the 5 or 6 FW circ pump drama all happened in less that 12 months.....

I have chucked out unused oil and fuel filters which had rust problems while still 'in the box'... but they were about 15/20 yo... I carry rather a lot of filters...

[Wotname]

Originally Posted by Dockhead

Just rotate them as you do regular maintenance. Simples. Impellers, filters, belts, and hoses are really no problem.
………

Don't do what I did -- buy a spare without verifying that it actually fits. I carried a spare starter for years, and at the moment when I needed it, it turned out to be the wrong part

Ouch…

You don't think rubber impellers have a shelf life???? That's good news!

Maybe I'm too cautious, in our work store many things have a shelf life, especially hoses, o rings, adhesives and all rubber type components - still, that's aviation for you - pedantic and particular

[Dockhead]

Originally Posted by Wotname

Ouch…

You don't think rubber impellers have a shelf life???? That's good news!

Maybe I'm too cautious, in our work store many things have a shelf life, especially hoses, o rings, adhesives and all rubber type components - still, that's aviation for you - pedantic and particular

No -- you misunderstood me. I said to ROTATE them -- use them up, don't leave them in stock. Every time I change an impeller, I buy a new one, and put that into spares. For the replacement, I take out of spares the oldest one I have. That way, the stock is constantly rotated, and belts, hoses, impellers never get old. Same with filters.

Rubber formulations are much better these days. My habits were formed from days when British sports cars used natural rubber seals which rotted on the shelf in two or three years, and would melt if you used any hydraulic fluid except some special Girling type. As a result, I have a habit of regularly replacing all hoses and never keep rubber parts in stock, although what I do is probably overkill considering how much better rubber is these days.

I just went through replacing all the tiny sea- and fresh water hoses on my turbocharged and intercooled Yanmar -- there are an amazing number of them, and this cost a lot of money. The engineer thought I was crazy ("if it ain't broke, don't fix it"), but it has been six years since I did it last.

This thread has reminded me that I need a fresh water circulation pump in spares.

[El Pinguino]

Originally Posted by Wotname

Ouch…

You don't think rubber impellers have a shelf life???? That's good news!

Maybe I'm too cautious, in our work store many things have a shelf life, especially hoses, o rings, adhesives and all rubber type components - still, that's aviation for you - pedantic and particular

Well... I think they do.... measured in years not days but still finite.

Years ago a chum... Australian boss of Twin Disc ...told me that was one of the reasons parts were so expensive....#1 inventory sat on the shelves for years
#2 every so many years they had to chuck out anything with rubber in it...

As an aside he also told me that anything they made was meant to be good for 10,000 hours ... after that you are one your own.

Similar to what my dick doctor ( aka the prostate man) says... when I hit 75 I'm out of warranty...

[GordMay]

The recommended shelf life generally associated with products fabricated from various polymers is listed below and is based on information provided in MIL-HDBK-695D Military Standardization Handbook Rubber Products: Recommended Shelf Life. These numbers represent average shelf life under normal dry/cool storage conditions and should be used for guidance purposes only. Shelf life varies depending on product specifications and compound design.

Common or Trade Name Recommended Shelf Life
Silicone 20 years
Viton®, Fluorel 20 years
Neoprene 5-10 years
EPDM 5-10 years
Butyl 5-10 years
Nitrile, NBR 5-10 years
SBR 3-5 years
Natural Rubber, Pure Gum 3-5 years

See also Technical Reference Bulletin - Rubber Shelf Life
➥ http://www.cmrubber.com/pdf/rubber_shelf_life.pdf

And ➥ http://www.emtengineering.com/wp-con...Shelf-Life.pdf

[Hud3]

I lived in the Tropics for eight years, and learned that many items made of polymeric materials would deteriorate much more rapidly than I was used to when I lived on the East Coast US. My shoe soles delaminated, elastic cuff and waist bands gave up the ghost, my bicycle tire sidewalls blew out, etc. Some of our female friends took to storing their panties in the freezer to extend the life of the waistband elastic! The other problem was rust. Without aggressive care, tools and metal parts rust very quickly during the "rainy" season.

So, if you plan to cruise in the Tropics, I'd suggest vac-sealing your spares using a food preserver device like FoodSaver, and storing them in the darkest, coolest space you can find.

[Dockhead]

Originally Posted by GordMay

The recommended shelf life generally associated with products fabricated from various polymers is listed below and is based on information provided in MIL-HDBK-695D Military Standardization Handbook Rubber Products: Recommended Shelf Life. These numbers represent average shelf life under normal dry/cool storage conditions and should be used for guidance purposes only. Shelf life varies depending on product specifications and compound design.

Common or Trade Name Recommended Shelf Life
Silicone 20 years
Viton®, Fluorel 20 years
Neoprene 5-10 years
EPDM 5-10 years
Butyl 5-10 years
Nitrile, NBR 5-10 years
SBR 3-5 years
Natural Rubber, Pure Gum 3-5 years

See also Technical Reference Bulletin - Rubber Shelf Life
➥ http://www.cmrubber.com/pdf/rubber_shelf_life.pdf

And ➥ http://www.emtengineering.com/wp-con...Shelf-Life.pdf

As always, you're a wealth of useful information, Gord!


No chance of any of my rubber engine or gensets exceeding those limits, but what about pump spares? Hmmm. Neoprene and nitrile bad in as little as 5 years? I wonder how old my pump and toilet spares were when I bought them? Hmmm.

[Nicholson58]

Originally Posted by Hud3

Some of our female friends took to storing their panties in the freezer to extend the life of the waistband elastic!

So, if you plan to cruise in the Tropics, I'd suggest vac-sealing your spares using a food preserver device like FoodSaver, and storing them in the darkest, coolest space you can find.

Maybe just don't wear panties?

When I built rubber powered airplanes in a previous life, we all used Glycerin or cod liver oil to keep the crappy rubber bands from rotting. I presume that keeping oxygen away might be key. Perhaps this technique might still be good. Otherwise, seal stuff in vac seal bags but with a purge of nitrogen first might help.

[hellosailor]

"What is the shelf life of common engine spares? "
What is the length of a piece of string?
You have to ask what each spare is made of, and how that material ages, and what the environmental factors are.


For instance, "rubber" parts may be silicon, butyl, Viton, all kinds of materials that age differently. I've seen the "rubber" straps on swim fins crack and rot in ten years, whole others have gone 20 without any sign of age. The ones that went 20? Were fed ArmorAll once in a while (which replaces plasticizers that normally gas off, and blocks oxygen absorbtion) and similarly, I've dusted other "rubber" parts with ordinary talc, which apparently prevents oxygen damage just as well.


The folks who make your belts, hoses, and engine mounts (Gates, Goodyear, Firestone, all of them) say to replace at five years, used or not used, because the materials WILL break down in that time. So the 12-year-old impeller? I'd toss it now, they are not designed or packaged to stay flexible and strong for that long. Then I'd take the 2 year old and apply some protection, and seal it up to keep more air out. I'd bet the newer one is significantly more flexible and springy when you compress the blades.


Distribution? You can only guess from the condition of the packaging, and the likely turnover at that supplier.


Air filter? Is it foam, cloth, or paper? Foams tend to be chemically bubbled in "rubbers" and often have cheap chemicals that eventually burn or melt the foam without any extra help. If it is crumbly or gummy, throw it out. Otherwise, clean cool dry storage is all you can do. Cloth doesn't have that problem (there are some made of cotton fibers over a metal matrix) and paper generally is cheap enough to make so that it also is stable.

" I am thinking the 12 year old belts will be reasonably safe to use if required as the original belts in service are still quite good." Nuh-uh. The folks who make them say otherwise, as above. Talc the spares, seal against air, and then they won't age as badly. Untreated? They're pat their designed lifetime already.

"The fuel filters (in original packing) should be fine - I assume!!!!"
Probably. Paper over a metal matrix, so that's relatively stable.


Some stuff has a shelf life of "forever". Some can be extended. The rest? Like fresh produce, it doesn't matter what you do, it rots as it sits there. Nothing you can do about that.

[secrabtree]

How long many rubber or rubber-like parts will last is, in many cases, highly dependent upon use. Unused it is often MUCH less than if used (proper use expected). Rubber that is intended to flex in use, like impellers and tires, will age if exposed to air and not used - they'll get brittle.