Spare Injector Storage

[eze2bme]

I have just returned from the Hatteras Owner's School this week and one topic of discussion by the engine guys at Jarrett Bay pertained to stored injectors in our spare parts inventory. I wanted to express their thoughts for all to consider and get any feedback.

I hope I got all this correct: The engine guys said that spare part injectors should be sealed in air tight containers to prevent them from drying out and becoming non-operational ... often leading to engine damage if used. They said that two (2) years is about the life expectancy of injectors not in air tight containers. They did say that the injectors could be tested by a mechanic by holding them upright and hitting the bottom with your hand ... and if a bit of fluid comes out the nozzle then they MAY still be OK. (Apparently the injectors have fluid in them from the factory.) If they pass this "slap" test and the levers are moving easily then they should be filled with something like WD40 or other water dispersant and sealed in air tight containers such as a vacuum food bag.

Any thoughts by you guys?

 

[Avenger]

Be careful with the "slap" test. We had a guy inject his hand doing that with a Cummins injector once. You'll get the same result if you hold a Detroit injector too close to the nozzle.

Otherwise the information sounds fine.

 

[krush]

Just use this: http://www.foodsaver.com/

 

[GJH]

Just use this: http://www.foodsaver.com/

Exactly. We discussed this solution at the class. These are a great thing to have on the boat for a variety of purposes.

 

[Genesis]

There should be FUEL in the injectors (or calibration oil) from the factory. Do not "slap test" them or you will pump it out. The inside of an injector has some pretty tight tolerances and rust and corrosion in there does bad things. You "slap test" it and then don't install it immediately and you've just removed the fuel that was protecting the insides from air. Now about replacing that (clean) fuel....

If you spray WD40 in there you'll contaminate it if there's any sort of dirt around the ports or in the tube you have in the WD40 can. You are using a can that you have laying around, right? A little bit of dirt that gets in the injector and you got problems. They have a tiny filter in the inlet side but.....

The caps (on the tip and connections) should never be removed unless the injector is about to be installed (for the tip) and the jumper port caps removed AFTER it is in and the jumper lines about to be connected. And incidentally (and in response to the two posts I just whacked that were more "baiting" games), that is "by the book" - caps never come off unless the injector is about to be installed/connected, and they go back on before you pull them, assuming you intend to re-use.

A "foodsaver" or similar is an excellent means of keeping air and moisture out and the oil they're full of in. Stored properly they keep forever.

 

[captddis]

Seems like the discussion got shorter? Only one way is the right way?

 

[eze2bme]

Genesis: I have spare injectors that I've had for five years. How can I tell if they are still good? They are Reliabuilt and in the boxes they came in. Thxs.

 

[captddis]

for a small fee an injection shop will test them.

 

[GJH]

Huh? all the posts are here. Not that Bill's has any value whatsoever, it's still here.

 

[Genesis]

Genesis: I have spare injectors that I've had for five years. How can I tell if they are still good? They are Reliabuilt and in the boxes they came in. Thxs.

Are they wrapped? (I've seen 'em come both ways - wrapped and thus "sealed", and not.)

If questionable, a decent diesel shop should be able to test them, as was noted. It is not possible to test them (other than checking to make sure the rack moves smoothly and for gross damage such as rust on the tip, etc) without proper equipment.

Salt air is hell on anything that can corrode.

(Yes, I have removed non-technical BS from the technical area, and I will do it again as many times as is necessary.)

 

[krush]

I don't see how WD40 would contaminate anything in storage, including an injector. The enemy is moisture and corrosion. I guess one could take a rubbermaid of diesel fuel and soak the entire injector in that for storage to be super safe. These are injectors that were designed in the 30's for goodness sakes!

From what I read in the other thread, the advice about WD40 in the injectors from storage came from Covington Diesel or Hatteras FACTORY guys. I personally wouldn't be scared to listen to them whether it is "by the book" or not....since this is their bread and butter business and they have more experience than any of us in it.

 

[Boatdaze2]

Help me out here, I want to be sure I understand all this. Factory guys explained how to check an injector, then fill it with WD40, or other water dispersent and seal it in vacuum bag? Now someone is saying do not use WD40 as it may have dirt in it. I can't count all the cans of WD40 I have gone through, used it to test for vacuum leaks in devices with orifices with openings in the ten thousanths of an inch, never had a dirt problem. Rust doesn't form in a can of WD40 as it is under pressure, and water can not enter.

I also wonder why anyone one would want to do a slap test unless they are ready to install the injector, and if you do a slap test how do you refill them?

I would think any company that is selling new injectors, or even rebuilt ones would know all about sealing them with fluid in them. If they aren't packaged in this manner why buy them?

I guess my real question here is what is the right way to test them, or maybe I should just call DD and ask them.

 

[Boatdaze2]

I don't see how WD40 would contaminate anything in storage, including an injector. The enemy is moisture and corrosion. I guess one could take a rubbermaid of diesel fuel and soak the entire injector in that for storage to be super safe. These are injectors that were designed in the 30's for goodness sakes!

From what I read in the other thread, the advice about WD40 in the injectors from storage came from Covington Diesel or Hatteras FACTORY guys. I personally wouldn't be scared to listen to them whether it is "by the book" or not....since this is their bread and butter business and they have more experience than any of us in it.

Sorry Mr. Krush sir, we must have been replying at the same time. I agree with what you stated, hopefully our posts won't get scratched and we can all learn the correct way.

 

[yachtsmanbill]

Installing a field tested unit isnt a problem. A week of sitting empty MAY promote some corrosion, but unless you wash them in hot water and leave them in the weather, I dont see a problem. For gosh sakes, these were designed in the '30s afterall! 'Ol Joe Farmer, if he was lucky enough to have a Detroit back then, burned whatever liquid fuel (oil not gas!) he could come across.
Ive always bled them one at a time on the starter until a few start hitting then continue until the engine is self sustaining. After all, a resident expert here mentioned that the rack return pressure to the tank is 60 PSI. I kinda doubt that figure as the return is open to atmosphere. The SUPPLY side is another matter.

 

[Genesis]

Installing a field tested unit isnt a problem. A week of sitting empty MAY promote some corrosion, but unless you wash them in hot water and leave them in the weather, I dont see a problem. For gosh sakes, these were designed in the '30s afterall! 'Ol Joe Farmer, if he was lucky enough to have a Detroit back then, burned whatever liquid fuel (oil not gas!) he could come across.

The fuel rails are on the clean side of the secondary filter. There is a small sintered filter in the inlet side of the injector which is a "last chance" sort of thing.

The issue comes about if any sort of dirt gets into the injector beyond said filter. Yes, 'Ol Joe Farmer ran whatever he wanted but that fuel still went through a filter before it got to Mr. Injector. You're proposing to squirt something in there without the benefit of filtration.

Ive always bled them one at a time on the starter until a few start hitting then continue until the engine is self sustaining. After all, a resident expert here mentioned that the rack return pressure to the tank is 60 PSI. I kinda doubt that figure as the return is open to atmosphere. The SUPPLY side is another matter.

The restrictor orifice is on the exit side of the fuel cooler; the entire system from the fuel pump to the restrictor orifice is under ~60psi when the engine is running. That includes both supply and return rails in the head and the fuel cooler itself. The return beyond the fuel cooler exit is open to the atmosphere; upstream of that exit it is under pressure due to the restrictor fitting at that point. Detroit injectors intentionally bypass a lot of fuel as it is used to cool the injector; without the restrictor fitting in the system the engine would not run correctly as inlet pressure would not be maintained (the injectors bypassing at any given time would cause the supply pressure in the rail to collapse.) The restrictor is usually at the exit side of the fuel cooler on marine engines so the fuel cooler is under positive pressure and a leak in the cooler does not cause seawater to be dumped into the fuel tank. On land-based engines it is frequently found at the exit of the return fuel rail in the cylinder head.

The issue isn't dirt in the WD40 in the can (obviously there isn't any) it's the dirt that is probably in and on the plastic tube coming from the can that you're going to use to direct the spray into the port. If your can of WD40 is like the one I have laying around my garage or in my boat, it's not pristine and new, and it has some WD40 in and on that tube from prior uses, which over time sitting in the toolbox will attract dirt. If you want to spray that into an injector, be my guest. I think it's a tremendously bad idea to stick anything other than clean, filtered oil in one and WD40 traveling down a tube that likely has grit and such in and on it is going to wash that dirt right into your spanking-new injector that should be all nice and clean inside - and contaminate it.

You might get away with that and you might not but I'll choose not to do it.

If you're gonna store a couple replacement injectors on the boat seal 'em in a vacuum-packed bag and forget about 'em until you need them. No air, no moisture, no corrosion and no problem.

 

[REBrueckner]

I've always understood spare injectors do have a shelf life....is corrosion the only issue??

I'm can't imagine that spraying some WD40 on an injector in storage, one not already in a sealed air tight container, would be worse than not spraying before sealing a homemade (baggie type) injector bag.

How about use a new can of spray dispersant?? If there is a tube on a used can, how about just spraying first into a rag, to clear the tube of possible contaminants, then spray the injector for protection, or removing the tube and then spraying the injector?? If the injector is already in a sealed bag, leaving it that way would seem most safe.

As I was reading this thread, I also wondered about storing spare injectors in a container of liquid diesel fuel...just enough to cover the injector(s). Say in a jar with a lid....

 

[Genesis]

Injectors have oil in them when shipped, and are capped on both ports and the nozzle. If undisturbed and sealed in a vacuum bag they should be good for a very long time.

The tips are particularly delicate (the holes actually) and should not be touched.

I've heard the "shelf life" thing too but I can't imagine why storing one in a vacuum-sealed bag in which the original oil is there when sealed, so it cannot get contaminants in it or suffer corrosion, would not result in a shelf life of decades. Mechanical stuff stored slathered in cosmoline can be fine decades later.

One place that is potentially important and non-obvious on an injector is the ridge at the bottom that locks into the injector tube. That's the compression seal for the cylinder so corrosion damage there would mean it would not seal in the hole properly.

If I was going to store them long-term I would take care not to disturb the original "as packed" condition (with oil in them) and would (without removing the nozzle guard or port covers) coat the sealing surface ridge with a light grease before vacuum-sealing it.

Before you install one check and make sure the rack does not bind; that moves the helix inside and that's all tight-tolerance stuff in there. If corrosion has gotten into the mechanism it will probably be detectable that way.

 

[Avenger]

I would think any company that is selling new injectors, or even rebuilt ones would know all about sealing them with fluid in them. If they aren't packaged in this manner why buy them?

Unless it's a military spec job most rebuilders and manufacturers don't sell products with the idea that you're going to store it for twenty years. They expect them to be installed and used. So if you're going to preserve it for future generations you'll have to do it yourself or special request it.

There is a small sintered filter in the inlet side of the injector which is a "last chance" sort of thing.

It's time to buy a new service manual. Detroit hasn't used a sintered filter since about the time they had two valves. Now they use a compressed mesh type as in the picture below. BTW, I really had to search to find an example of a sintered bronze filter for the picture.

As far as WD-40, obviously normal precautions like wiping off the straw and spritzing a little bit out to clear the straw would apply. But otherwise you're not going to introduce anything harmful that way. These injectors weren't built in clean-room conditions and they aren't rebuilt that way either. Treating them like medical equipment isn't necessary. Most people would be shocked at what actually passes through conventional injection systems without doing any harm at all.

 

[MikeP]

I'm impressed, you guys actually carry spare injectors? Wow.

I realize that Hatt originally supplied a spare set with the boat but I've never carried any. I figure that they are easy enough to get - heck, you can find them in a little Mexican village in the middle of nowhere - so it's not like you won't be able to locate any if you need them.

OTOH, they don't take up much space so there's no big downside to carrying them. Of course, that thinking - "it doesn't take much space," coupled with the similar "It doesn't weigh that much"- is one of the reasons that it takes what feels like days to get our 53 up on plane and WOT to stay there.

 

[Angela]

I'm impressed, you guys actually carry spare injectors? Wow.

I realize that Hatt originally supplied a spare set with the boat but I've never carried any.

There were two boxes of injectors on our boat when we got her. I wonder how old they are. Box is labeled Reliabuilt. They are in a cardboard box, wrapped in plastic like a box of tea, and I've kept them in a plastic box with a lid, but down in the genny room...is heat down there bad for them?