Man, am I a happy camper to have a new topic section to post various repairs, tips, and tricks that others may find useful. I'll get things started here with a repair I had to do recently, something I've never done before. The boss wanted me to have injectors of a Mitsubishi 6D24 in a Kobelco SK480 rebuilt. Easy enough job, a task I've done many times before. But on this one, had a problem with #1 injector, it pulled the bronze injector cup out with injector. You can view what happened at post #11 of The Suck Bucket thread at this link: Typically, what you would do is remove the cylinder head, and send the head to a head rebuilder and have them go through it and install a new injector cup. And although this engine has an individual head for each cylinder, removing it would have been quite a project because Mitsu used studs for all the exhaust and intake manifold ports, meaning, they would have to be removed. Very rusted nuts and studs on the exhaust manifold, the whole deal would have been a time consuming mess, when all I need to do is install a new injector cup, and the bronze cup was available from Kobelco. Fortunately for me, I happen to have a head rebuilder very near me. I got a new cup from Kobelco, and made a little trip to talk to the fellas at Diesel Head and Parts, where they were kind enough to give me some info and a little crash course on how this process works. And they provided me with a supplier for a key part I needed to perform repair. A big shout out and many thanks to Earl and Darrell at Diesel Head for taking their work time to meet with me and provide me with much needed info. If I do need a head rebuilt, you can bet I'll be sending it to them and support them. http://www.dieseldhp.com/ Well, let's get started with this repair. Here's the hole in the head that I need to install a new bronze injector cup. Here's the new bronze cup. Now here's the trick. It's simple enough to drop the cup into the head, it will just drop in there. The coolant seal at the large end (outside end) is provided by the o-ring. The small tip end, which goes into the cylinder combustion chamber, is the end that requires special tooling to seal. According to Darrell at Diesel Head, it's actually quite simple, you have to use a tool that will expand the tip on the bronze cup by twenty thousandths, known as swaging, to seat and seal the tip in the head. Now, I could have got this tooling from Kobelco, at a cost of over $1,300.00 (not kidding), and that was dealer cost. Instead, the guys at Diesel Head provided me with a contact of a company that makes special tools for engine rebuilders where I was able to get the key tool I needed, that is, the ball broach. I contacted K-Line tools, and they referred me to a distributor in Alabama that provided me with the needed ball broach for $46.00 + ground shipping. Now that's what I'm talking about! Yes! http://www.klineind.com/ Here's the ball broach. It's kinda hard to see, but on the end of the tool to the left side, you'll notice two bulges in the tool shaft, that would be the swaging balls. You simply drive this tool through the hole in the tip end of injector cup and it expands the tip. The first ball expands the tip by twenty thousandths, the second ball is an additional one thousandth to account for metal "flowback", or retraction, after the balls are driven through. In the normal world, the head shop simply drives this tool through the cup, and pulls it out the bottom side. Well, my head is still on the engine, can't pull out the bottom side, I have to pull it back out the same way it went in. So I had a machine shop cut the 5/16" fine threads on the driving end of ball broach, and had them fabricate an installation clamping tool, that was over $900.00 from Kobelco (again, not kidding), that would press the cup in the head, set the o-ring, and hold cup in place while I drive the ball broach in and pull it back out. I also had machine shop fab a driving head to screw onto ball broach so I wouldn't damage threads while driving it in. Here's the tooling set up, all I have to do is drive the ball broach through far enough for second ball to punch through. The tool from K-Line was exactly enough, and no more, to get the job done.
Ok, here's the process. Darrell said to put some red Loctite on the tip, then install the cup in the hole. I squirted some tapping fluid in the bottom of the cup and on the ball broach to lubricate while driving broach. Installed the assembled tooling, used two bolts in the injector retainer holes to press cup in place and seat o-ring. For bronze cups that don't have a seal o-ring, the outer end will have to be swaged with a larger ball broach to make the seal. On this one, the o-ring does the job. Then simply drive it home with smooth taps from a ball peen hammer.
Removed the driving head, then simply pulled ball broach out using the 5/16" nut as a pulling device. Had to use a socket as an extension bushing to pull the ball broach past last ball. There ya go...done! This whole process took me, maybe, 15 minutes. Installed all the injectors, good to go. Fifteen minutes of easy work compared to how many hours, and parts, to remove that head, have it repaired, and re-install it on the engine. Oh, torque everything, adjust valves. Hmm, I prefer the 15 minute easy job in this case.
The correct tooling alway makes the job go easy. We use a similar style of cup on a 3116. It is copper and is swedged in place. We also use a high strength retaining compound to seal it.
It used to be the end of the copper would stick through the head and you had another tool that trimmed the end off flush with the surface of the head. Maybe the Mitsu copper doesn't go all the way through?
I reckon it doesn't John C, although I didn't have any way to measure the length of the hole in the head, but I did hold the new cup alongside the old one and there was no visible difference in lenght. You can see the old injector cup with injector still stuck in it at post #11 of suck bucket thread.
ATCO whatever you are getting paid, it isn't enough.
LoL...I think we all have experience with that EGS.
It been a few years since I had one of those engines down but I was thinking that in addition to using the ball broach you also swedged the tube from the backside? But then again I may be thinking back to my Fiat Allis days.
You would be right motrack, Darrell told me Fiat Allis did that. But in this case, that's why I went to talk to him, he's the pro that does these things daily, and if he was confident it would work, I sure wasn't going to argue with a pro. I'm just happy it worked flawlessly.
Nice job on the fix. Now that you have one done how long do you think it will take for the rest of them to come loose. You might as well maximize the income potential of that new tool
I havent laid hands on a Mitsubishi engine in years. They just seem to run forever given reasonable care. Nice to know you can install the injector tube with out pulling the head. I will file that in my memory banks for future reference.
Well, the thing about this one John was some brick axe woodshed mechanic had been in here previously and actually coated the injectors, yes the injectors, with grey RTV. Injectors #2 through #6 came out with no real incident, but I'm thinking this shade tree installed #1 first, and it was really coated with RTV, literally glued it into the injector cup. I didn't think I was ever going to get that thing out. Well, actually, I didn't. LoL...yanked the cup! After it came out, I had to clamp the injector lockdown tabs in a vise and really work to get that cup off the injector. Never in my wildest brain farts would I apply RTV to an injector. :tong
Great job as alway atco, and thats for sharing things like this do stick in the mind for again! and thanks for the link to the website!!:drinkup Now for the stuipid question, whats RTV?? I'm sure we got it over here just prob called somthing else:beatsme
RTV (Room Temperature Vulcanising) is Silicone Rubber
Yep, that would be it...Silicone. You know, the stuff that shade tree wrenches love to squirt on gasket surfaces like it's toothpaste, then it oozes out the edges. Yeah, that stuff. :tong
And it squeezes to the inside too and gets caught in filter screens such as an oil pump pickup and worse.Great thread Atco!!Ron G