I developed a crack in my 22R engine near the left engine mount. It is weldably accessable if I remove the oil pan. The crack is not involved with the engine mount bolts, its only about two inches long and only leaks oil. Since it's at the bottom of the block it's accessable by removing the oil pan. I'd like to touch it up with a nickle rod but I was convinced to apply a traveling salesman approach to the oil leak. That application failed to prevent the leak so I plan on welding it. Is there a special nickle rod I should be using? Does the surrounding area have to be red hot? It was mentioned I wouldn't have to get it too hot if I welded the area slow......almost like.....tack welding...... and pinging the weld (ball bean HAMMER)......allowing a stress relief. If not, how hot does the surrounding metal have to be before I apply the nickle rod? What is the proper sequence to preheat? And the probable disasters that I should avoid.
I am kind of a nut when it comes to crack repairs but here goes. Before I started welding I would want to grind out the entire crack to within 1/16 or so of the depth of the metal. Since the crack is contaminated with engine oil and probably plastic from the traveling salesman's magic elixer I would preheat carefully until the area no longer smokes when you take the torch away. Red hot is unnecessary. I would use a filler that claims to produce a machinable result on cast iron, others will probably make more detailed suggestions here. Weld an inch or so at a time, don't weave a lot, don't try to fill the whole grove at once. Peen each section as you go, I like to use the pointy end of a dull slag hammer, it needs to fit in the groove so you can hit the weld itself. Do the whole job without letting the work cool then cool it as slowly as possible. Slow cooling may be difficult, if the engine is apart you can bury it in dry wood ashes or similar material, if it's together it's more difficult, perhaps a heat lamp on the work area will help.
Bill
As a weldor, mechanic,race car builder, i would not weld that crack . when it cools it most likely will crack especially if its in the car. if it was my toyota I'd drill2 small hole at each end of the crack to keep it from gettin bigger, then grind the surface down to get the sand that is embedded in the iron off,(from when it was cast) this is called casting flash. Then I'd braze it leaving a nice thick bead. still try not to heat it excessively. Good luck!
BigRob you bring back memories - when we were kids, some of us built go-carts using those 10 horsepower Briggs & Statton engines used in mortar mixers. They were notorious for cracks in the crankcase and that's exactly the way they were repaired. We took the blocks down to an old bicycle mechanic and that's the way he repaired them.
Bob G.
I was actually taught this by an oldsea dog when Iwas just a pup! many moons ago.
FWIW :-)
I used charcoal as a post heat/slow cooling process on a large cast lathe base. It actually worked alright. I did get some hairline spreading of one of the larger cracks, but overall, the repair came out well. An old school neighbor told me about the charcoal.
Especially for a first time attempt at repairing a large crack on cast iron. :-)
S.W.
Cast iron needs to be preheated to 700 deg. F. before welding. Drill a hole at ither end of the crack to prevent it from spreding further, then of course grind a bevel and clean it up/out. Use a back step when welding with an electrode for cast iron. After welding one inch at a time let it cool to 500 deg. F. then reheat to 700 deg. F. then weld the next inch (repeat as necassary). When the final bead is welded let it cool to 500 heat it up a little more, cool to below 500 and then back to 500,then cool to ambient tempature,,,the after heating will cause the weld to maintain its form and not warp, crack, or lose ductility.
Good luck. It is time consuming but can be done.
Kinda off topic, but not. When I worked at the Cat dealer we had a D11 throw a counterweight off the crankshaft through the side of the block. We had to strip it down completely and then they sent it off to someplace in Texas with all the pieces we could find. It came back maybe two weeks later and the crack.....rrrrr, hole was gone. Not sure exactly what process they used or even who it was but it was like new. Kinda saved the customer around $50,000, that's what they wanted for a new block. This was an 800hp, 2200 foot pounds of torque beast and it held up well.
OK this may seem odd, since I do not think welding on cast iron is a good thing. I might suggest using a lock and stitch method. It looks like stitches and you can bring the crack back in without having to preheat, weld, and post heat or cool slowly. Just a thought.
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