Cast iron repair?

[Arc weld]

George I never made any comments about plugs for cast iron. No ear broke off. The threaded boss pulled off and I don't know why. There is no gasket. There are 2 O-rings that seal the oil ports into the oil cooler. I can only guess that maybe I had the bolt a little tight and when the oil cooler got hot it expanded some and caused the break. It certainly didn't break when I tightened the bolt and wasn't leaking at first. I listed the other rod because it is similar to the the ones yomax4 suggested. That's why I had his name at the beginning of the paragraph. I think it's part of the block and I can't put a whole lot of heat to it without removing the injection pump and a whole lot of other parts. If it is separate, I'll take it off and braze it.

 

[CliffordK]

Here is a list of thermal expansion of metals.
Cast Iron is relatively low.
Thermal Expansion Metals

Lots of other similar resources on the web.

You would likely do best both in the short-term (making the repair), and the long-term if you try to match the welding rod to the metal. Silver & silver alloys have almost twice the thermal expansion of iron. Brasses and bronzes are also high. Nickel and steel (iron/carbon) alloys are a bit closer, but there is also a lot of variation with stainless.

Is the thermal expansion coefficient(s) listed on your rod?

 

[the old grind]

... Is the thermal expansion coefficient(s) listed on your rod?

The young guy in the video did peen the bajeebers out of his passes to minimize & redirect stresses (dilute?) with the no-preheat technique (tho' linear vs radial). It has to be important, but causes me to wonder if access to the full perimeter of the boss might limit the OP's options in any way.

Could bronze weld or brazing be built up a bit extra around the joint for strength/longevity, or would that be a bad thing to consider??

 

[Arc weld]

Over peening can sometimes be worse than not peening at all. The weld done in the video was more of an experiment and done in about most ideal conditions possible. I would love it if I could take the piece off and and repair in ideal conditions. A big problem I have is heat. I can't put a lot of heat at the repair because the injection pump isn't too far away. I don't want to have to tear the engine down to the bare block. I have heard and read about the cold welding technique and was hoping someone has done it successfully. It sounds like yomax4 has some experience with it. I'm almost certain it is cast iron and so I want to use the right rod for the repair. Doing some more reading 55 or 60% nickel rods might be a better choice.

 

[yomax4]

Another option that has worked for me on engine blocks is Spray Powder. I had a similar situation like yours on a corvette engine that had a threaded boss type protrusion that had an eye bolt that held a spring. it was 5/16 I think. I did 2 tacks opposite of eack other and then took a die grinder with a carbide burr and made small bevels one either side of the tacks. I spray powdered the bevels and the boss together. I let it cool some and took the die grinder to the tack sides and beveled them a little. went over it with spray powder and it was done. What I like about spray powder for cast repairs is that it doesn't zap your work with a bunch of votage scattering molecules all over the place. No peening and anyone can do it. Just a thought.

 

[Arc weld]

I'm kind of out in the middle of nowhere and don't have a spray torch. Wouldn't the 2 tacks scatter the molecules anyway? Just asking cause I don't really want to have to tear the engine apart to repair it.

 

[yomax4]

The tacks would do less that a complete weld. In your case, I would just do 2 second tacks all the way around it and let it cool after each 2 tacks. It will hold and you will be done with this..

 

[Arc weld]

I haven't been on this forum for very long so don't know too many people here. It sounds like you have experience doing similar repairs to what I have. You listed some very high tensile rods that were similar to some I can easily get. I don't know if these are the best rods to use or if I should use lower tensile nickel based rods or something else. I need to do a good repair with what I have to work because I don't want to lose the oil and destroy the engine. I was thinking of putting some kind of gasket seal on the oil cooler as well incase the repair didn't hold. Your insight is appreciated.:thumbsup:

 

[pjbci]

Personally, i would try to braze it on but heres an option that keeps popping into my head but havnt mention it because im afraid everybody will laugh at me but anyway. Have you considered trying JB Weld to either hold it on or make a complete new boss out of. You could make a form out of a piece of plastic pipe the right length the fill it with JB weld then drill and tap it. I dont use it but maybe once every couple of years but it always does what i ask of it.

 

[Arc weld]

Epoxy was mentioned. That's what JB weld is. I think I'm going to weld it but want to use the best choice of welding rod.

 

[jwmorris]

You had that in post #2, if you don't have to drill and tap.

 

[the old grind]

Arc weld, we're throwing a lot at you, and good stuff too, but might be more help sorting the options with some pics. Can we help you with that??

I still say how well you can access the repair area to prep/weld/braze/whatever may bear somewhat on what will best git 'er done. btw: On some page you might have to refresh us on what gear/tools you can take to the job way out there ... ....

 

[Arc weld]

I don't have a TIG torch. yomax4 suggested a 312 stainless type rod if I don't know what it is. It is cast iron. I've also read that a 55-60% nickel rod would work in addition to silicon bronze. I hope I can just clean up the threads after welding. I'll leave a bolt in while welding. I've read other info that just says nickel rods but doesn't mention if they are 55% or 99%. That's why I'm asking. I have seen cast iron welded with stainless, nickel and other types of rods. If I'm just doing quick tacks I need a rod that will get good fusion right away. What little cast I've done seems to go on cold and not completely fuse at the start.

 

[Arc weld]

I have an SA 200, a die grinder and a torch set. There is a raised boss about 3/4" in diameter that is threaded for the oil cooler. The threaded part of this boss pulled off, It's about 3/8" thick. I was planning to bevel the broken piece and grind a little on the other side to clean it up for the weld. The injection pump is about 6 to 8" above this and there is another bracket with gaskets and such on the back of the engine about 8" away. Where the repair is is relatively easy to get at. I think if I put most of the bevel on the broken piece, I should be able to see what I'm doing pretty well.

 

[CliffordK]

If you don't want the bolt welded into the place, (or if it is a problem for it to become permanently part of the engine), I'd probably remove it.

I suppose you could put in a stud instead of a bolt, which might not be a bad idea. Then if it is welded in place, it is ok. If it comes out, it isn't bad either.

You can purchase "bottoming taps" for tapping into blind holes.

 

[jwmorris]

If you think you might weld a bolt in place use a brass or aluminum bolt. Brass bolts you might find at a local boat supply house but both are easy to find on the internet.

Is there anything else close to the broken boss? Maybe you just fabricate a bracket that hooks to other mounting bolts and has a provision to attach your oil cooler.? At least then you would be working with a familiar metal.

 

[Mark @ Everlast]

I'd suggest brazing it. It's a sure fire method, and relatively strong if done properly. You have a 931? I've had the injection pump off of one. Just keep the pump and engine in the same place you took it off, (and mark the teeth position together if possible) it won't be a big issue.

 

[EdGranelli]

Without a picture it is hard to give advice. Can you use a mirror and take a picture that way? Anyhow, here is an interesting alternative to a permanent repair if there is room. Speaking of room can you bend up a piece of tin to keep the heat away from the pump and its lines? I went to Spring Carlisle and watched the demonstration of a torch. The gentleman had an old exhaust manifold that had slits cut in it. He used an old dirty piston ring, they are cast iron and I did not know that, preheated the small manifold, heated the piston ring and dipped it in the flux and proceeded to weld the slit! He made it look easy. After he welded it he ran the torch over the piece to take the stress out of the welded area. The best part is it is soft and can be drilled and tapped if needed. This is the location of a video demonstration of the torch. I do not know how to add the link but it is easy enough to type it in. torchweld.com - youtube To watch the cast iron welding only, move the button to about 3:30 seconds into the video.

 

[Arc weld]

I have gas welded cast iron in school as well as brazed it. Where I work we sell cooling gel that can be sprayed on to keep parts cool but for any O/A process, you need LOTS of heat(800deg's. +). I have read several techniques on the cold repair method yomax4 suggested and this looks like the easiest repair for me. I just want to figure out the best rod to use.