Seized Injectors - Need Ideas to Remove!

[NoTies]

Flame temperature in a diesel engine can reach over 2000 degrees celcius so no problem applying intense localised heat but you need to use a heat sink to be totally safe. Submerge the head in a pan of water with just the area to be heated above the surface then let rip. Don't use excessive oxygen as you can end up with thermic lance and that will really ruin your day.

[Wotname]

Originally Posted by sailah

Electron discharge machine. Basically dissolves metal. Super precise, that what they use to remove broken taps.

For heating, you don't want to torch in 1 spot on cast thats asking for a cracked head. Heat the entire head up gently and evenly. Put in cold oven or grill and then turn heat on and let it ramp up slowly in stages. Work up to 225C in stages like 125 for 30 min then 175 etc..

Shocking the valve body seat with ice isn't going to hurt anything or risk cracking it but you want to apply the ice or cooling specifically to this area to get differential thermal expansion working in your favor to break the rust bond.

Then apply good penetrating fluid, put back in oven and turn oven down in stages then off. You want to heat and cool cast iron slowly to prevent warping or cracks.

If this were mine, I'd do this a few times over a couple days then on the final day I'd slam it with the impact gun right after i cooled the valve body.

Actually I'd do the impact first after i heated it once because I'm impatient and i have a milling machine

I would not attempt using Mapp or oxy acetylene because the danger of localized warping or cracking is to high with a precision surface in my opinion and i have both available in my shop.

I'd also check head for flatness after doing this since i just went through a warped head and had to get it machined

Let's see if I have understood this correctly.

Slowly heat the head in stages up to 225C then locally shock cool the valve body seat with ice. Then apply penetrant to the problem area and pop it back into the oven to cool in stages.

Do it again as many times as I can before I get impatient and then whack the impact gun on it immediately after the final shock cooling.

Correct???


And any particular reason for 225C rather say 200 or 250 ????

[coopec43]

Sorry I can't help you.


Are these clips of any use?

https://www.youtube.com/watch?v=7hEbCcOgKL8

https://www.youtube.com/watch?v=xBslHDZXwKU

https://www.youtube.com/watch?v=NL8JI10Du18

Clive

[Wotname]

^^ thanks for posting these clips but unfortunately those injectors are just "kiddy stuck" and the methods used don't cut the mustard for really "mountain man on steroids seized" injectors.

[coopec43]

Originally Posted by Wotname

^^ thanks for posting these clips but unfortunately those injectors are just "kiddy stuck" and the methods used don't cut the mustard for really "mountain man on steroids seized" injectors.

Well what about this then?

https://www.ogsmechanics.com/service...xhall-renault/


broken stud – seized injectors - thread repairs - Welcome to Adelaide ...


https://www.adelaidecylinderheads.com.au/products-cat.aspx?Id=30
We are seeing more & more the INJECTORS & GLOW PLUGS seizing in the ALLOY DIESEL HEADS so we have the capabilities to remove them if required



Clive

[sailah]

Originally Posted by Wotname

Let's see if I have understood this correctly.

Slowly heat the head in stages up to 225C then locally shock cool the valve body seat with ice. Then apply penetrant to the problem area and pop it back into the oven to cool in stages.

Do it again as many times as I can before I get impatient and then whack the impact gun on it immediately after the final shock cooling.

Correct???


And any particular reason for 225C rather say 200 or 250 ????

Pretty much. I was welding a cast iron exhaust manifold for a buddy by tig brazing using silicon bronze a pipe nipple to the elbow. My old timer welder said to heat up cast iron in an oven first and get it to 450F degrees which seems to be close to 225C. No other real reason you aren't going to hurt it if you get to 250C.

And yes, my experience is to heat cast iron slowly. Cold oven, let it ramp up in 3 stages, but fully heat soaked at each stage. How long that will take is up to how thick the part is. You're just giving it time to acclimate.

Once the entire part is proper hot, and 225C is pretty hot, you cool the part where you want the thermal differential. Cast iron holds heat really well so you have plenty of time to do this. I'd be icing maybe even spraying/flooding water on the valve body. Blow it off, soak with penetrant. Put back in oven and cool it off as slowly as you heated it.

Yes this is a very conservative approach and you may very well achieve the same result by torching the part with a rosebud but I think the risk is high doing that.

I use the thermal differential all the time when installing bearings. I place bearing on a lab hot plate, heat until I just see the oil flashing off the bearing race. Drop on shaft, done. You can easily get 0.05mm on smaller parts just from heat and that's plenty to break rust bond.

I think there are plenty of ideas in this thread, I have used others mentioned and had success.

No matter how you do it, heat & impact are your 2 friends, and heat is probably the most effective.

I have used electrolysis bath to remove rust from parts but not in the manner you are doing. Just heavily rusted tools etc. It does work well, you won't hurt anything. I use a large HP DC lab power supply but you can also use a battery charger or 12V battery. Then a plate some wires and washing soda. Lots of Youtube videos on the how to.

[Wotname]

Thanks sailah, very much appreciated.

Right now I am considering three options.
Your method as just described.
Using the engine to fire them out.
Electrolysis bath (assuming it is rust that is holding it together).

[sailah]

The welding of a nut trick also works really well on steel stuff I've used that many times esp on fasteners where you twist the head off and the stud is now flush with the part and nothing to grab. First time i did it i had a beer! Helps to have a tig welder.

I've also used welding of a bearing race when it's stuck in a bore. You run a bead directly on the race and when the weld cools it shrinks. Race falls right out. Also a beer moment!

Good luck!

[ggray]

I don't have time to look thru all responses so this might have been suggested.

One injector was stuck on my 3GM 30, and I bought a slugging wrench to loosen it with.

[Ex-Calif]

In regards to your question about overheating the head and warping it. As someone said combustion temperatures can be really high.

Also once disassembled completely you should sheck the flatness of the head and block anyway to ensure the gasket seals properly. Sometimes you can hand resurface the head and or block using again a parallel bar.

Worst case is you take the head to a machine shop and have it milled and surfaced.

At this point it is critical to not do any permanent damage to the head while trying to get this done. If it feels you've gone to far get thee to a machine shop - they know how to do this!

Look for a smallish pop & son type place that does hot rods etc. They are usually really flexible and experienced.

[coopec43]

A lot of olden day mechanics swore by iodine to loosen up engine studs.

[kmacdonald]

If the injectors are seized that bad, scrap the engine. It probably ingested salt water. Cut your loses now.

Or get a new head and injectors: https://www.hoyetractor.com/CTGY/2QM20.htm

[GeneM]

I made a puller for mine. It uses a 1 1/4 inch steel pipe that sits over the injector hole and bottoms nicely on the head. I welded a nut on the bottom of a bolt that fits the injector top. Before welding, put a large washer and travel nut above the welded bolt.
Put the pipe over the injector and screw on the welded nut to the injector. Tighten the nut down on the washer so the bolt travels up.
You may have to resolve the fix it or break it.

[jimbunyard]

Regarding using some kind of dissolving method, maybe you can modify this approach. Skip to 14:45 to get to the pertinent part; some of the video is pretty cheesy.

https://www.youtube.com/watch?v=zFa4Hfs81kE

My experience is that cast iron is fairly forgiving, get all your ducks in a row, heat head to 500-600 F, toss some ice chips into the valve cup, attach your slide hammer (if you can rig up a way to twist it at the same time, much the better), and hit it with the slide. I bet the 'stuckness' won't survive three cycles. Or alternate the heating/cooling/twisting slide hammering with a heating/cooling/impact gun cycle. At some point it almost becomes a matter of pride to not take it to the machine shop...

Beyond some kind of penetrant, I'd really try and stay away of the hassle of dissolving chemicals.

[RaymondR]

Originally Posted by boden36

A good machine shop should be able to make up a dolly to press on the combustion chamber end of the injector, whilst properly supporting the head. A decent sized press should make short work of it. Be prepared to throw the injector away!



Regards,
Richard.

Definately the better solution and if the dolly is made to fit the injector end properly the method most likely to be effective without destroying the injector.