Found a crack in the block

Bolts

Bolts

Well-known member
I was pressure testing a 59AB block when I discovered a very thin crack up inside the middle exhaust port. It's close to the outside. Is it possible to fix this by boring the port out slightly and inserting a press fitted sleeve?
 
I've never heard of doing it that way,
Most methods are going to be pinning, or welding.
Can you get at it very easy?
 
Bolts said:
I was pressure testing a 59AB block when I discovered a very thin crack up inside the middle exhaust port. It's close to the outside. Is it possible to fix this by boring the port out slightly and inserting a press fitted sleeve?
Click to expand...

Can you post a picture? Hard for me to visualize this.
 
Ralph I don't think you can get at it with a drill. A welder can reach it, but I've heard welding isn't a very good practice, don't know. I've also heard if you get it hot you can weld it using cast iron rods. Have you ever had success welding cast iron?
 
The crack is a tiny line slightly above the casting mark and to the left of it. In one picture the blob on the crack is from the Windex as it continues to bubble after I wiped most of it away so I could take the pictures.
 

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I would first clean that area with a die grinder and sandpaper roll and try to determine how much material there is to work with. I use a sonic tester with a probe that is designed to go into ports. Without knowing this, might bore into that area and find you've got nothing to push the sleeve into. If the block was otherwise good, I might see if there is a furnace block welder in the area (which are getting hard to find). Or, somebody like lockn' stitch could pin it.
 
The problem I see with just attempting a sleeve is it doesn't stop the crack progression. It needs to be drilled at each end of the crack to stop it before attempting any other repairs. If you were just wanting to seal the leak a water coolant sealer would do that, but again there is nothing to stop the crack from progressing with the heating and cooling cycles of the engine.
 
I would think it could be welded.
Yes I have welded exhaust manifolds, some with great success, some not. I have never welded a block before, but have seen it done successfully.

I think if you don't want to try a sealer or such, then it might be saved by welding.
 
Cast iron is tricky to weld. It has to be heated as a complete block to a very high temp before welding begins then cooled slowly after completion. It could be brazed too but pinning may be a thought.
 
Tricky to pin something in a tube cracked across...can´t get any locks in there to keep it from getting wider.
How about a threaded sleave if there is meat enough in the walls...that would keep it from openin up...nothing like a good challenge !
 
I agree with "JSeery" about stopping the crack progression. Getting a drill in there would seem to be problematic.
 
I'm struggling to think how I'd go about fixing it, but both sides of the metal are relatively low pressure areas, the water jacket, less than 15 psi, the exhaust only has pressure due to resistance. I'd take a chance and vee it out and cold weld it. I'd then use some leak stopper in the water jacket. I must admit I'd only try and repair that one if I had absolutely no other choice. I would also say I'd not throw a lot of money at it too.

I'd think about brazing it, but the pre heat would be really difficult.

Mart.
 
Cast iron really sucks up the heat so it would take a while to get it to a dull red in the 1200 *F range. A person has to use a lot of O/A gas to get it there. Plenty of borax powder flux would be needed too. Cool down would have to be as slow as possible. I don't know how thin the casting is in that port either so a sonic check would be a good idea as previously mentioned. Brazing alloys don't like aluminum oxide or other grit grinding products so clean up would be better by filing and wire brushing. Not a job for the faint at heart.
 
What was the test pressure? Were you testing with air? Was there any sign that water was actually leaking there? I wouldn't be inclined to do anything unless there was really a problem evident.
 
Cut your losses and find another block.Any repair here would need to be done by someplace that has the skill set and the cost would be more than another block.The chances of being successful on your own with welding,pins and other attempts with a sucess are very limited. Just my 2¢

R
 
I use to weld ALMOST any cast iron by getting a bonfire going around the part to be welded , drag the part out ( after a good heating ) weld it up using a nickel rod , put it back inthe Fire and cover with ashes , coal etc , let cool naturally till the fire is out and cool . Pray it doesn't rain !
 
Preheat is usually around 800* F and that is a good temp to start and stop at. Only the local weld area would need to get up to 1200 F or so. The braze would have to be left thick around the crack area to give it some strength. This might choke the port down a bit but I doubt it would hurt the performance much. Just getting a drill in there to relieve the crack would be tough. I have a 90 degree drill that uses 1/4"-28 drill bits but even with a short bit I don't know if it would fit in there.

Electric arc welding changes the local surface temp a lot and real fast so that is what can do the cracking since the temp is all localized and the rest is cold unless the block is preheated properly. Ronnie may have the best advice on this. This is not an easy fix and few if any would guarantee it either.
 
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