A piece of my engine block fell off

I just got a CJ5 that I'm working on putting back together since it is entirely apart. I was putting on a new timing chain and cleaning the gasket surface and a little chunk of the block fell off... It was glued on, probably will JB. Can something like that be welded back on, by a professional? Or should I replace the block? It was rebuilt 7500 miles ago so I'd prefer not to replace it.

Thanks

 

a good welder should be able to do that....

might even consider taking it to an engine shop or machine shop after so they can grind the sealing surface smooth again.

i think its fixable for sure

 

JMO - unless there's something special about this engine, get another block. Just not worth it to have it welded. 258s are cheap and easily found from private party sources - any 232 or 258 from '70 through 1980 will work fine as a block donor (the 232 from before 1971 is not the same).

A 232 is the same block, but a different crank, rods and pistons (shorter stroke), and you can probably find a 232 for free or nearly free.

For the 232 or the 258, will be some minor differences between the heads from year to year. I suggest you use the head from the donor engine - they are all equivalent except for things like rocker type, pushrod length, etc.

 

Well...that piece really has nothing to do with the structural integrity of the block...So I don't feel you need to replace the block...You could leave it out...but it would leak, right?
Looks as if the motor is out of your Jeep. Find a guy that can weld cast (properly) and have it put back on. After all...it's really not holding anything to speak of.

 

Also.......
If you are a semi-decent welder yourself...I could walk you through how to weld it back on, if you have the right equipment...it would be easy.

 

Confirm the price with your welder before you commit

 

Another thing I was thinking of...You might want to check your timing cover to see if it's warped... that could cause that...Probably not the case...but put a straight edge on it anyway.

 

The timing cover is straight.

I'll check around town in the next couple days to see where I can get the welding done and a quote for it.

 

didnt think of that....but i agree

in many cases brazing can be just as strong if not stronger than welds.

modern brazing isnt like the old school brazing that wouldn't hold up much....I think there's still a stigma about it

 

Brazing it would hold just fine. On another note...welding something like this is not that big of a deal either. Preheating is not necessary for this type of fix. See...the temperature where cast iron becomes unstable is like 1450 degrees...The weld will bring it above that temp...but as long as it is not for an extended period of time, it will be fine.
If you were going to do this yourself...it sounds as if your going to have it done...but if you were...this is what to do...
Clean both parts as good as you can, apply a small amount of heat to the part to be welded...This idea here is just so it is not cold. Heating it to around 100 degrees will be just fine. If you can't hold your hand on it...then it's too hot. With it warm...you are ready to begin welding. You will want to use a rod meant for such a thing...Lincoln makes a rod called "softweld" you would want a softweld 99NI (or alike). You want to keep the overall temp down while welding...so you should only weld a very sort piece at a time. Peen the short weld...when you can touch it with your bare hand...you can weld another short piece...Repeat this until done. If you did this correctly...it will not crack or give you any problems from there on.

 

Cast iron is supposed to be pre heated for a proper weld. Vibration contributes to failure afterwards if there is any flaw. We run into this periodically with ship parts- now we nearly always just get a new part based on past experience.

 

Ideally, yes....preheat if it's possible...but this will be fine without the preheat. I've had success with it many times when welding an engine block in frame or in boat.
Even Lincoln themselves have a how to on it.
http://www.lincolnelectric.com/knowledge/articles/content/castironpreheat.asp

To Heat, or not to Heat

In general, it is preferred to weld cast iron with preheat--and lots of it. But, another way to successfully weld cast iron is to keep it cool--not cold, but cool. Below, both methods will be described. However, once you select a method, stick with it. Keep it hot, or keep it cool, but don't change horses in the middle of the stream!

Welding Techniques with Preheat

Preheating the cast iron part before welding will slow the cooling rate of the weld, and the region surround the weld. It is always preferred to heat the entire casting, if possible. Typical preheat temperatures are 500-1200 degrees F. Don’t heat over 1400 degrees F since that will put the material into the critical temperature range. Preheat the part slowly and uniformly.

Weld using a low current, to minimize admixture, and residual stresses. In some cases, it may be necessary to restrict the welds to small, approximately 1-inch long segments to prevent the build up of residual stresses that can lead to cracking. Peening of weld beads can be helpful in this regard as well.

After welding, allow the part to slowly cool. Wrapping the casting in an insulating blanket, or burying it in dry sand, will help slow cooling rates, and reduce cracking tendencies.

Welding Techniques without Preheat

The size of the casting, or other circumstances, may require that the repair be made without preheat. When this is the case, the part needs to be kept cool, but not cold.

Raising the casting temperature to 100 degrees F is helpful. If the part is on an engine, it may be possible to run it for a few minutes to obtain this temperature. Never heat the casting so hot that you cannot place your bare hand on it.

Make short, approximately 1” long welds. Peening after welding is important with this technique. Allow the weld and the casting to cool. Do not accelerate the rate of cooling with water or compressed air. It may be possible to weld in another area of the casting while the previous weld cools. All craters should be filled. Whenever possible, the beads should be deposited in the same direction, and it is preferred that the ends of parallel beads not line up with each other.

 

To properly weld this piece, it should be chamfered, and welded all around. You can't just weld the outside, and expect it to last forever.
So, it would have to be disassembled to get at the inside.

 

Find an old machine shop. I had an starter ear welded back on to a 350 for 50. A good shop with experience will find this an everyday thing or tell you that JB weld will be fine.

 

I had a 78 that had a casting fault just in front of the fuel pump in the space you can see in the picture. It seeped oil, epoxy held it for 100k. That sure is a clean break.

 

Since there really is no strain on it....and some of today's epoxies are shockingly strong...that would most likely hold it. Not something that I personally would do...but it would probably work. After all...what you're really doing here is just sealing off an oil leak.

 

I agree. Clean off all of the oil residue and braze it. I have seen farm tractor cases that broke in half that were brazed back together so strength isn't an issue.

RSN

 

The "welding" of cast iron is usually a brazing operation, with a filler rod made chiefly of nickel being used although true welding with cast iron rods is also available.

 

Clean it up real good and fasten it back on to the timing cover and seal everything up with a lot of silicone. That should take care of any leaks which is your main concern.