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.