Cracked block repairing - I didn’t find a relatable thread in the archives

Repairing a cracked block.

All it takes is a pristine shop, all the necessary equipment, and skilled hands-on.


Amazing skills!

That is not a mere cracked block! it is a busted block, big time!

I am unsure of the materials involved> Cast iron? Brass or bronze repair material. i have read of those!

Alloy? Never heard of a flame repair? Tig is usual method!

I dimly recall a fellow trying to braze a freze caused crack in a flat head. Only partly worked?


How does this not crack?!?

Properly-brazed cast-iron actually is quite durable and usually very long lived.

How long does it last?

No idea, but … he has apparently done enough similar repairs over the years to become quite skilled at it, so it must last long enough to make it worthwhile to repair them.

My guess is that the block is cast iron, and I’ve heard that welding cast iron is possible, just not easy, and that it needs to be heated a certain amount first.

He certainly knows where to put the heat sink bricks and protect things.

I found it interesting that they used just the right size steel rod … which didn’t look like it was “just laying around” … to fit the crank mains, lubed it, installed the mains, and checked that it rotated before doing any other work.

Want to make sure it fits, doesn’t warp during heating, and still fits/works after it cools.

That definitely was not his first ‘let’s see if I can fix something like this’ attempt at doing it. Everyone knew what needed to be done and when to do it.

Do it to a V12 reving at 6500 rpm? Probably not.

Do it to a truck or something which likely revs much lower and has much less horsepower and torque? Apparently it works.

Well, when I tried to weld a cracked cat iron exhaust manifold it cracked right next to my weld when it cooled down. I was told to hear the whole manifold, weld it, and then cool it down very slowly. I didn’t try than and bought another one instead.

Did you heat the part in an oven? When brazing cast-iron, it has to be very, very hot.

No and that was probably my mistake. But in the video I didn’t set the block being heated either.

This guy uses a type of sprinkle-on flux: I used coated eutectic bronze. You’ll see where he preheats the piece.

I had an old 220v range hooked up in my shop, and I’d crank it up to 500F, and preheat parts that way.

Well that could have been half as long and still have the relevant information covered.
Still it looks like he resurrected the item.

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imo… not worth the costs… different motor or whatever… I always felt you shouldn’t fall in love with a car as it has no conscience or remorse or pity for the owner… worse than the wrath of a divorcee.

In some countries, there may be no other feasible options … make the repairs, whatever is necessary, and get something back running again.

I just recalled a sucess in fixing! I had a primitve self propelled lawn mwer. Cheapie! It had a shft on the deck for the drive. the ends housed in brass trunions. well, the alignment was poor. One brass trunion wore artly away. I amazed my self. i added brass ro resore the arch. tehn drilled it again. i got better alignent, i think. it served me f a very long time.

Modern bangers are having engine blocks made of aluminium. You can repair these with any AC TIG welder. Cast iron ones are weldable as well - the only additional workload relates to equal heat-up. Small cracks are standard for repairs. Missing chunks of block probably not…