How to Clean Injectors

[corn_flake]

My AP suggests to clean the injectors.  So off I go to look up Lycoming Service Instructions.  https://www.lycoming.com/sites/default/files/Cleaning Fuel Injector Nozzles.pdf

It was mentioned in Lycoming's instructions to not soak the "Packing Rings" or it may swell.  Does these injectors have o-rings of sorts that needs to be removed?  

I know the injectors insert can be removed, but I can't find a way to remove the the inserts without damaging them with a plier. 

How do you all clean your injectors?  Soak it as is or some disassembly is required?  

In my effort to make this post more visually interesting, I'm including a picture of my injectors.  They are from GAMI.  Each injector is individually marked with cylinder number.  No way to get them mix up!!

 

 

[Guest]

Your fuel injection nozzles don’t have O rings or rubber seals.  Follow the Lycoming instructions using Hobbs #9 solvent.  Do not over torque the line nut.

Clarence

[Shadrach]

Not sure if Clarence is a victim of auto correct but the cleaner to which I think he is referring is Hoppe's #9.  It's gun barrel bore cleaner.  To build on Clarence's  (@M20Doc) warning, I have four cracked fuel injectors in my hangar caused by someone over torquing the B-nuts (attaches fuel line to injector).  Have no idea who did it or when it happened. They did not leak but were discovered when I removed the engine in 2009.  Make sure you A&P is involved in this process as it is well beyond the scope of FAR 43.7. Once installed, I would leave those injectors alone unless the give cause to disturb them.  A closed system is normally a clean system. Cleaning them for S's and G's does little more than risk introducing lint, fibers, et al. to the system. 

 

[cliffy]

Also be careful on install as the threads between the injector and the cylinder can be cross threaded VERY easily

I've used ultrasonic cleaners to clean them and still you have to visually insect them very carefully for any foreign matter in the injector

Generally speaking if they aren't causing a problem leave them alone.  If your GAMI spread is OK then the injectors are OK. 

Keep a good eye on each cylinder on the first T/O after you replace them to make sure none go lean. 

I have had several instances of uncontrollable engines on Navajos on T/O due to dirt in an injector, or, a cylinder going lean on throttle up. 

But again, if it ain't broke don't fix it. Maintenance induced problems can creep in. 

[mike_elliott]

Overtorquing them into the cylinder head can cause cracks in the head also. 

[RobertGary1]

If you’re working from the manual it spells it out. The inserts don’t need pliers to take out. Rather they will fall out. They are difficult to replace so be very careful with the inserts and don’t lose them. 

 

-Robert 

[PT20J]

And don’t mix up the restrictors between the nozzles and don’t poke anything in the holes.

 15-812_b.pdf

[corn_flake]

Thanks Guys on the tips!!  

Is there a torque spec for the b-nut?  

While Lycoming doc recommend 60 in lb on the injector, it didn't make any mention for the b-nut.  

[Guest]

2 hours ago, Shadrach said:

Not sure if Clarence is a victim of auto correct but the cleaner to which I think he is referring is Hoppe's #9.  It's gun barrel bore cleaner.  To build on Clarence's  (@M20Doc) warning, I have four cracked fuel injectors in my hangar caused by someone over torquing the B-nuts (attaches fuel line to injector).  Have no idea who did it or when it happened. They did not leak but were discovered when I removed the engine in 2009.  Make sure you A&P is involved in this process as it is well beyond the scope of FAR 43.7. Once installed, I would leave those injectors alone unless the give cause to disturb them.  A closed system is normally a clean system. Cleaning them for S's and G's does little more than risk introducing lint, fibers, et al. to the system. 

 

It’s an Apple thing I guess, my iPad knows about Hobbs meters but not Hoppe’s #9.  Cleanliness is next to Godliness when it comes to tools for working on fuel injectors.

Clarence

 

[RobertGary1]

15 minutes ago, corn_flake said:

Thanks Guys on the tips!!  

Is there a torque spec for the b-nut?  

While Lycoming doc recommend 60 in lb on the injector, it didn't make any mention for the b-nut.  

Also note that Lycoming wants a specific orientation of the injector. There is a dot on it. Its suppose to face up as I recall so that affects the ultimate torque as well.

 

-Robert

[Shadrach]

3 minutes ago, M20Doc said:

It’s an Apple thing I guess, my iPad knows about Hobbs meters but not Hoppe’s #9.  Cleanliness is next to Godliness when it comes to tools for working on fuel injectors.

Clarence

 

Me too. Talk to text is worse.  My iPhone once translated something to the effect of "I will be late" into "I'll masterb@%&".  That text was for my mother in law.  So glad I reviewed before sending...

[Guest]

Just now, Shadrach said:

Me too. Talk to text is worse.  My iPhone once translated something to the effect of "I will be late" into "I'll masterb@%&".  That text was for my mother in law.  So glad I reviewed before sending...

That could cause a bit of embarrassment.

Clarence

[corn_flake]

31 minutes ago, RobertGary1 said:

Also note that Lycoming wants a specific orientation of the injector. There is a dot on it. Its suppose to face up as I recall so that affects the ultimate torque as well.

 

-Robert

Actually, Lycoming injector has letter "A", which it should be at 6 o'clock position.  Since my are Gami, it has both nozzle size and the cylinder number stamped on two sides of the injector housing.   I got a call into Gami to ask how I should position the injectors.  

 

[StevenL757]

1 hour ago, Shadrach said:

Me too. Talk to text is worse.  My iPhone once translated something to the effect of "I will be late" into "I'll masterb@%&".  That text was for my mother in law.  So glad I reviewed before sending...

Hilarious.  My mother-in-law would've been shocked, then laughed her a - - off.  :-)

[Shadrach]

Just now, StevenL757 said:

Hilarious.  My mother-in-law would've been shocked, then laughed her a - - off.  :-)

Mine probably would have done the same. However, she was my mother in law to be at the time. I was mortified at the thought.

[StevenL757]

I can imagine.  :-)

Ain't technology great?

[PT20J]

4 hours ago, RobertGary1 said:

Also note that Lycoming wants a specific orientation of the injector. There is a dot on it. Its suppose to face up as I recall so that affects the ultimate torque as well.

 

-Robert

I think that only applies if the injector is horizontal which is not the case in the IO-360 unless you mount the engine vertically as in some helicopters.

From SI 1275C

In normally aspirated  engines where the  nozzles, P/N  LW­18265  (see Figure  2), are installed  horizontally, particular  attention must be  paid  to  the  identification marks stamped on one of the hex flats on the nozzle body. This mark  is located  180° from the  air bleed  hole  and must appear  in the  lower side  of the  nozzle to assure that the air­bleed  hole is on top in order to reduce fuel bleeding  from  this opening  just after  shutdown. To ensure  nozzle  is correctly torqued, tighten the nozzle to 60 in.­lbs. torque. Then continue to tighten until the letter or number stamped on the hex of the nozzle body points downward.

Skip

[RobertGary1]

Just now, PT20J said:

I think that only applies if the injector is horizontal which is not the case in the IO-360 unless you mount the engine vertically as in some helicopters.

From SI 1275C

In normally aspirated  engines where the  nozzles, P/N  LW­18265  (see Figure  2), are installed  horizontally, particular  attention must be  paid  to  the  identification marks stamped on one of the hex flats on the nozzle body. This mark  is located  180° from the  air bleed  hole  and must appear  in the  lower side  of the  nozzle to assure that the air­bleed  hole is on top in order to reduce fuel bleeding  from  this opening  just after  shutdown. To ensure  nozzle  is correctly torqued, tighten the nozzle to 60 in.­lbs. torque. Then continue to tighten until the letter or number stamped on the hex of the nozzle body points downward.

Skip

When my new Lycoming IO-360 came from the factory I had one injector plug almost immediately on install. When I called Lycoming they cautioned me to be aware of the orientation of the injector when I reinstalled it. Honestly if I had to do it again I would have only removed the insert, since that is what plugs up.

-Robert

[McMooney]

6 hours ago, Shadrach said:

Not sure if Clarence is a victim of auto correct but the cleaner to which I think he is referring is Hoppe's #9.  It's gun barrel bore cleaner.  To build on Clarence's  (@M20Doc) warning, I have four cracked fuel injectors in my hangar caused by someone over torquing the B-nuts (attaches fuel line to injector).  Have no idea who did it or when it happened. They did not leak but were discovered when I removed the engine in 2009.  Make sure you A&P is involved in this process as it is well beyond the scope of FAR 43.7. Once installed, I would leave those injectors alone unless the give cause to disturb them.  A closed system is normally a clean system. Cleaning them for S's and G's does little more than risk introducing lint, fibers, et al. to the system. 

 

good stuff, i actually used to work for the company that makes Hoppes

[Guest]

6 hours ago, corn_flake said:

Thanks Guys on the tips!!  

Is there a torque spec for the b-nut?  

While Lycoming doc recommend 60 in lb on the injector, it didn't make any mention for the b-nut.  

The info Skip posted says 25 to 50”pounds, I’d always used 30” pounds and never had one come loose.

Clarence

[corn_flake]

Thanks Everyone for the tips.  

Here is an "after" picture.  They looks almost new!!  

I do have tip to share.  If you are considering doing the same, you may want to skip Harbor Freight Ultra Sonic cleaner.  The Hoppe's solution desolves the plastic on the HF Ultra Sonic cleaner after only one use.  The device is also way too big for injectors cleaning.  This mean you have to use more Hoppe's solvent.  

 

  

[PT20J]

The mechanic at the museum, puts parts in a small container of solvent and sets it on the bench grinder frame for a few minutes which provides enough vibration for a gentle cleaning action.

Skip

[bradp]

I had a fuel line crack because of years of on off from injectors getting cleaned.  Be careful.  This is one of those critical areas where you want to know what you’re doing. 

[carusoam]

1) Somebody posted a pic of a broken injector tube the other day...

 

2) Orientation is important...

When you get it wrong... you post a pic with a question...  

Something about a blue stain coming out of the injector...

 

3) Great pics, Flake!

4) Hoppes (Siri doesn’t like this word at all) is a great lead dissolver... hence the heavy use by some arms cleaners... it also has been known to dissolve the lead out of the surface of some metal alloys... follow the instructions...

5) For readers following along or coming in later... it is important to put the injectors back in their original cylinders... don’t mix them up... especially if they are Gamis... somebody has paid extra to figure it out already... don’t accidentally add pilot induce randomness... 

6) I like flake’s mechanic... Flake has learned a ton of detail for this important job...

7) One important thing to know... how to tell when a FI needs to be cleaned... the Gami spread has an outlier...

Flake did you get to do a Gami spread test? Was it above 0.5 gph and three were close together compared to the odd ball...

PP memories only, not a mechanic...
 

Best regards,

-a-

hoppes site... https://www.hoppes.com/Hoppes/media/Files/15BSH7651_HoppesGunCareGuide_Final_Lores.pdf

[DonMuncy]

5 hours ago, corn_flake said:

I do have tip to share.  If you are considering doing the same, you may want to skip Harbor Freight Ultra Sonic cleaner.  The Hoppe's solution desolves the plastic on the HF Ultra Sonic cleaner after only one use.  The device is also way too big for injectors cleaning.  This mean you have to use more Hoppe's solvent.  

 

You might pour some Hoppes #9 into a plastic sandwich baggie to make  sure it won't dissolve the baggie. If not, pour enough in the baggie to cover the injectors. Then put water into the ultra sonic cleaner, place the plastic baggie into the water and run it. The sonic waves transmit through the water, then thru the cleaner. Works well.