Seized Injectors - Need Ideas to Remove!

[Wotname]

I have a Yanmar 2QM20 head (on the bench) and the injectors are well and truly seized / stuck in the head and I am looking for ideas or advice on how to remove them.

So far I have tried various penetrating fluids and rust releasing agents (Mouse Milk, H-72 Reducteur, ATF/Acetone mix, diesel and others). Each have been left soaking for several days.

I have tried rotating the injector body using a breaker bar with about 4' of extension pipe - no movement.

I have tried a slide hammer (attached to the 8mm thread at the top of the injector) after each soaking but even with repeated blows dozens and dozens of times - no movement.

I need much more force or serious heat or to remove the rust which presumably is holding the injector in place. Quite possibly the injectors have never been removed in 40 years of service.

I haven't tried an air impact driver but feel it could likely damage the injector flats and I can't see anyway of using more force than the slide hammer.

I reluctant to use serious heat as it might damage the head or injector nozzle and housing.

Currently considering making up an electrolysis bath to see it that will remove the rust but I have never tried this and I wonder if it will cause other damage to the head.

Also thinking of refitting the head to the engine, leaving the injector clamps slightly loose, spinning the engine over with the starter motor while squirting some diesel into the inlet manifold which the hope that it will fire a couple of time and blow the injector out.

As this engine uses a pre-combustion chamber, I can't see anyway of forcing the injector out from the other side.

Perhaps I can make something to replace the top nut but I can't really see any way to exert more force to pull the injector out.

Any ideas (or cautions) are very welcome at this stage but please don't suggest soaking it with penetrating fluid - that hasn't worked so far

[steve77]

The only suggestion I can offer is to fabricate a socket that will fit over the flats and use a pneumatic impact wrench to try and rotate the injector body. I’ve never tried this, but it’s the only suggestion I have. Best of luck!

Steve

[sailah]

Using a breaker bar without impact seems like a great way to snap something off. You need some type of thermal cycling to break the rust bond.

I've used my gas grill to heat things up my wife would find objectionable in the oven.

I'd try heating the entire assembly up by putting it on a tray so flames aren't licking the metal. Get it proper warm. Then use a piece of ice or dry ice on the injector body to shrink it. It doesn't take much to break the rust bond. Try doing this a few cycles. I'd also apply a good penetrant like Kroil, not sure what you are using but Kroil is my absolute favorite for things where I have one shot. Apply penetrant after you've iced the injector body.

After I had heat cycled the head, I'd modify an impact socket to fit those flats. Then hit it with a real impact. I use an 18V Makita 1/2" impact which will spin off anything, has more power than my largest pneumatic Ingersoll Rand.

If all those options fail, I'd set up the head on a milling machine and bore out the injector using carbide endmill and punch out the pieces. Or take to a machine shop and have them EDM it with a tap remover.

[sailah]

Sorry maybe I misunderstood. The injector body is threaded into head? And actual injector is just inserted into this body and held in place by some threaded cap?

So the injector could come straight out without being unthreaded?

I'd attempt to remove the entire assembly first. This allows you to try heating the body with a torch and icing the injector without having to heat up the entire head for every cycle. Or alternatively submerging the entire assembly in acetone/ATF and letting soak for awhile.

[roberttigar]

The last time I did this I had 2 of 4 injectors stuck. Try this: loosen the bolts holding the stuck injectors-do not remove them. Use the starter to turn the engine over several times. The compression may loosen them. Bob

[motion30]

I think heat is your friend here.

[Techtool]

If you have the stones try heat and quench. The two metals (cast and tool steel) expand and contract at different rates and warming and cooling will break the rust.

[sazarac]

Take the head to a machine shop and have them press the injectors out. Then buy new injectors.

[jimbunyard]

Perseverance.


If you haven't, clamp or bolt the head to something immovable while you're slide-hammering.


Heat cycling may help. Use acetylene, carefully, if you have it.


Your slide hammer looks big enough, but pictures can be deceiving. Is the slide at least 4-5 lbs?


If you can get a helper, have them try and turn the injector while you slide hammer.


Fabricate a puller, put as much tension as you dare on it, and leave it overnight.


It will eventually pop free.

[Ex-Calif]

This is pretty much how I would proceed with a couple of modifications

- I would spray with PB Blaster
- Use a propane torch to heat the head - Don't be scared to get it hot, like close to glowing red. It will take a lot of heat to get the metal hot. The PB Blaster will smoke and may even catch fire - don't panic - LOL...
- Use a turkey baster to then douse the injector housing with ice water
- Repeat a couple of times, reapplying the PB Blaster
- I would "gingerly" zap it with an impact gun between heat cycles - the vibration should help in breaking the bond

- I am very partial to PB Blaster. I restore classic MGBs and this stuff worked a treat on 40 year old suspension joints that were totally rusted together. In 40 years of twisting wrenches it has turned out to be the best for me.

- If it hasn't broken free by now I would try the breaker bar again.
- If all that didn't work I would try the impact more aggressively but I'd be careful at this stage before surrendering and taking it to a machine shop.

Originally Posted by sailah

Using a breaker bar without impact seems like a great way to snap something off. You need some type of thermal cycling to break the rust bond.

I've used my gas grill to heat things up my wife would find objectionable in the oven.

I'd try heating the entire assembly up by putting it on a tray so flames aren't licking the metal. Get it proper warm. Then use a piece of ice or dry ice on the injector body to shrink it. It doesn't take much to break the rust bond. Try doing this a few cycles. I'd also apply a good penetrant like Kroil, not sure what you are using but Kroil is my absolute favorite for things where I have one shot. Apply penetrant after you've iced the injector body.

After I had heat cycled the head, I'd modify an impact socket to fit those flats. Then hit it with a real impact. I use an 18V Makita 1/2" impact which will spin off anything, has more power than my largest pneumatic Ingersoll Rand.

If all those options fail, I'd set up the head on a milling machine and bore out the injector using carbide endmill and punch out the pieces. Or take to a machine shop and have them EDM it with a tap remover.

[Oceanride007]

The manufacturer would have had a special pry bar.

Use your penetrant.

But anyway, as the injectors are so old, you are going to replace anyway, do you have access to the injector Nozzle on the combustion chamber side make up a dolly to fit the Injector and hit it with Engineers hammer. Dolly is usually made of softer material, with luck the nozzle will survive.
I never seen a injector that is screwed in, they all have clamp arrangement.


More common than you think but usually its leaky Combustion gas that locks them in place.

[shakey doug]

Photo #3. This is not part of the injector but the combustion anti chamber [ Lombardo chamber] this motor has indirect injection.
6''x1'' brass stock and a minimum 5 pound maul or larger and SHOCK HIT the lower section at the same time try to wiggle it.

[Wotname]

A couple more images so everyone is on the same page

It is the valve nut that is stuck and I can dissemble the injector down to this nut and valve body. I can remove valve itself but so far I haven't tried real hard to remove the valve body. However I will attempt to remove the valve body before using any heat.

It was unsaid but I assumed apparent that I am trying not to damage anything. It is easy to get stuff apart if you are happy to break things!!!!!!

[Wotname]

Originally Posted by shakey doug

Photo #3. This is not part of the injector but the combustion anti chamber [ Lombardo chamber] this motor has indirect injection.
6''x1'' brass stock and a minimum 5 pound maul or larger and SHOCK HIT the lower section at the same time try to wiggle it.

Yes, that's correct. Due to its shape, I don't want to belt the pointy end of the pre com chamber.

[Wotname]

Originally Posted by roberttigar

The last time I did this I had 2 of 4 injectors stuck. Try this: loosen the bolts holding the stuck injectors-do not remove them. Use the starter to turn the engine over several times. The compression may loosen them. Bob

Yes, this will be tried if other methods don't work and I was planning to spray some diesel into the inlet manifold at the same time hoping for for ignition and the extra pressure created will free the injector.

But I would have to reassemble the head and refit to the engine so this is more of a last resort idea.