Case 680E

[Eugen]

@thebuildist I think the piston grooves can be fixed on the lathe so they're not narrower at the dent. I'm more worried about what @DavidBarkey said about the cylinder. A dent in the cylinder is not going to be easily fixed. I will check today but most likely that's the case.

[Timj]

@thebuildist I think the piston grooves can be fixed on the lathe so they're not narrower at the dent. I'm more worried about what @DavidBarkey said about the cylinder. A dent in the cylinder is not going to be easily fixed. I will check today but most likely that's the case.

I agree Eugen, clean it up so the new seals fit right. A little bypass internally will only take away a little force.
A good look inside like Dave said

[Eugen]

Dave was right, I can see a little indentation on the inside waaay far fr the opening. The fact that it's not big may be the silver lining here. The piston has three grooves. The grooves on the ends of the piston host what they call bearings, a tough band which is actually split by design. They cannot seal, so I think their purpose is to keep the rod true within the cylinder. The middle one is the real seal, and that doesn't seem to have real damage. It's comprised of a square profile of very rubbery material on the inner side of the groove and the yellow band of tougher material on top of it.

My hope is that it will not damage the actual seal over time. Will have to align the dent in the cylinder with the dent on the piston when it goes back together.

[Spike188]

This is thinking outside the cylinder. Ha ha you thought I would say box. Risking barrel shrinkage. Welding a bolt the the dent and pulling it. Preferably a cold pull or heating to pull. Another method would be a pipe expander modified to reach the dent. Use a pipe expander and heat the dent area. This method would allow for a light duty expander, ie harbor freight or princes to be modified for one time use.
The cheapest repair might be ordering seamless pipe, the cutting the barrel pin and fitting off of the damaged cylinder. It would require having the seal end machined and threaded.

[Spike188]

This is thinking outside the cylinder. Ha ha you thought I would say box. Risking barrel shrinkage, welding a bolt to the dent and pulling it. Preferably a cold pull but heating the area would make the required force needed for the pull. Also the heat could be localized to control where the stretch would occur.

Another method would be a pipe expander modified to reach the dent. Use a pipe expander and heat the dent area. This method would allow for a light duty expander, ie harbor freight or princes to be modified for one time use.

The cheapest repair might be ordering seamless pipe, the cutting the barrel pin and fitting off of the damaged cylinder. It would require having the seal end machined and threaded.

[Eugen]

Hm.. good ideas here! This pipe expander goes to 4" but collects are aluminum. If the dent would be heated cherry red this might work right? Or put a piece of large diameter steel pipe on the aluminum collet. Which I don't have.

[DavidBarkey]

Hm.. good ideas here! This pipe expander goes to 4" but collects are aluminum. If the dent would be heated cherry red this might work right? Or put a piece of large diameter steel pipe on the aluminum collet. Which I don't have.

what is the bore size ? heat with a steel pipe sleeve over an expander . The sleeve will need a slit in it and some way of holding on the expander so it comes back out all together . Preset stops for the right distance down the tube . A way of holding the expander from turning and pulling it back out . depending on how far down it is you may need a extra long 1/2" drive extention . I have a 3' one you can borrow . You will need to have the expander above the dent and quickly slide into place when area is red hot . you will not have much time between red hot and to cool to work . When the dent is pushed back then it will need to be honed .
If not done , it will fail again .

[Eugen]

It's 4 inch, the bore. I'm kicking myself for not getting those 4" steel pipe pieces I saw at the garbage at the university one day

And what to hone it with. The dent is far about 3 feet down the cylinder.

[JSinMO]

I can’t help you with the dent I’m reading this and learning. But what about this attached to a 4 foot rod to a drill to hone it?

[Timj]

I can’t help you with the dent I’m reading this and learning. But what about this attached to a 4 foot rod to a drill to hone it?DC9B37FA-FB0F-49A0-979D-FD6CDE02B837.png

I had thought about one of those hones, but other than a quick clean up, I think it would also enlarge the the entire diameter, and not take just the hump down. You would need some type of line bore.