From time to time here I have seen different views on repairing blocks that have suffered freeze cracks. Now that don't happen here, but I always thought that brazing the crack would be eaisest. So when a guy gave me a 26 Dodge four with a big piece of the water jacket pushed out I thought I would try it. Looks like to me that it works pretty good. I ground everything as clean as I could. Stop drilled the crack on both ends. I didn't want a hole to fill with brass so i drilled with a #7 bit and tapped 1/4-20 and stuck in some threaded rod cut off short. It was a "U" shapped crack with some pretty good gaps between surfaces so I installed more 1/4-20 plugs where needed and a few 5/16. It took a while to heat the thicker parts of the block to flow the brass so I had to get comfertable. Then oil started to come out of the iron so I had to stop, cool, clean. It took a while but I pluged the crack enough to hold water. I expect that If I ever use the block I'll add Bars-Leak. Don't know if the pictures will show anything.
It won't be long before you have another sprinkler can/lawn ornament. The best way to fix that crack is to find another block....however, '26 Dodge blocks don't grow on trees. Second best would be to spend the money on furnace welding/brazing the cracks shut...another process we've used a couple of times with success is spray welding the crack. The third choice is 'pinning' the cracks shut - if the crack was small enough. Too bad.....It may be tough to repair the block correctly with all that braze stuffed in there. I commend you on your efforts to save an old and very hard to find block, however, if your serious about having the block become a truely serviceable part again your best bet is to find professional help with it before you preceed any further. -Bigchief.
Time will tell. I don't see the water jacket being a structural part of the block. The cooling system is not persurized. We will see.
I have welded up cast Iron gas engines (hit & miss)...we used cast rod.. pre heat the hell out of it first.. I tried brazing a 350 chev block once, wasted a lot of gas and rods.. didn't work.. 1939fiat
I have found welding cast iron it is better to leave all the weld showing when you grind the weld back you weaken the repair .Hit and miss mostly miss
My next choice would have been to cut the bad part out and fab a new replacement I think. There were some pretty big gaps of missing iron and the whole thing had bent away from the block. I tried to push it back, but I pushed pretty hard with no luck and didn't want to push harder. I've brazed cast iron before with good results, but not for anything like this. What do you think will happen? Cracks from around the Brass/iron joint or just the brass giving up?
I second what BigChief told you,mostly because I've heard the same words come out of his mouth about a motor of mine, of course mine wasn't as hard to find as yours.
Cast Iron needs to be perfectly clean to be Brazed successfully. I've done several repairs on cast iron, no problems so far.
Often your best bet to repair a broken casting is to visit a large indistrial repair operation. Some place that caters to the shipping or heavy manufacturing industries. If you had a tugboat with a broken casting, or a printing press a few hundred feet long, you call in these repair guys (since there are no tugboat or printing press junkyards lol). My experience has always been that they treat these 'little' jobs as a pleasant diversion. Little to them, big to us. They are always happy to be working on something that does not require a crane to move around. Most times they will not even ask for payment, or it will be a pittance. They have the expertise and materials to get it going again. Whenever you are faced with something big, seek help from someone for whom that particular problem is something little.
Life is an experment. Sometimes I'm told something won't work and it works OK for me. ("57 Ford head on a '32 Plymouth block) Sometimes I'm told something won't work and they were right. But I still need to find out for myself. The bad news is that If I'm ever going to really find out how this worked, I need to do lots more work to it. I planned on extensive brazing on the intake tract, no water jacket involved. Making new Main caps. Paying for a billet crank and maybe rods. Making a head. Cam gear. Doing something about valves. Intake, headers. Bolt the thing to a SBF blowshield. If the whole side falls off the water jacket I'll be really unhappy.
Couple years back I was in a fellas garage where he had just finished welding up a 392 block for his supercharged drag car. Seems a previous mishap allowed the the piston to exit the block the hard way - through the side. BIG HOLE. What amazed me the most was the bore job through the weld was invisible. This fella had cut a section out of another "disabled" 392 block so the IRON would match and he welded it up using cast rod. He used Tempil sticks and a torpedo heater to control - preheat - inner pass temps - and cool down. I was quite impressed. This guy was GOOD!!!! After seeing this I always figured THIS was a method worth exploring.
I've had really good luck using a tig and solid nickle rod. I preheat the part with a rosebud and keep it as hot as can stand it while welding, a helper is needed with big parts to keep the heat distributed throughout the piece. Once welding the cast kinda gasses up on the first pass but I just keep feeding the nickle to it and it fills in and smoothes out. As soon as the weld is done I bury the entire piece in sand for about an hour, its amazing how well the sand holds the heat in and brings the temp. down slowly and evenly. I've repaired freeze cracks, starter ears, manifolds, and just yesterday repaired a cracked crankcase breather flange on a big EMD locomotive engine using this method. I personally have never had much luck brazing cast, it always seeps around the edge of the repair with me.
Looks good to me. W'ere only talking about 210 degrees or so, and the braze rod will withstand 700 degrees. So, it should hold up.. Mikey
The first engine I ran in the roadster was a 2 liter Pinto. Ran in G/GR. Around '85 or '86. It had a Raised port Paul Gomm head. There was extensive brazing build up of the exhaust port floors, done with a torch. to achieve this Raised Port. The intake ports were done with JB Weld it looked like. I made many, many passes at the lakes with that motor. Went 128 mph. 14.26-98 mph in the quarter. Never had any trouble with that braze melting or comming out. It's still in there today. I don't think anyone expects the brass to melt, they just expect it to leak.
I brazed up a 350 Chevy block that froze . I put it in a car and it held water and ran fine. After about a 100 miles the cylinder nearest the crack let go. It was junk after that.
We had a 305 in shop class that had been brazed ON THE CYLINDER FACE! My shop teacher couldn't explain how it worked, and didn't believe it until we ran it on the stand. It was torn down twice a semester for 4 years and always worked. And we ran it hard on the stand, we wanted to see it blow, but it wouldn't. you couldn't catch a fingernail on it, even after all we put it through.
We have a SBC in a circle track car with a significant crack due to frozen water. Threw a can of moroso ceramic sealer in there to limp it thru the first weeks of the 2005(!) season and it's still in the car, not leaking. In a car that turns 7K rpm, overheats regularly, and does all the other wonderful smashup things dirt trackers do. Bar's leak wouldn't be my first choice, but you're a smart dude so there must be a reason Good luck!
theres a new welding rod out for cast it's called cool weld i think, no pre heat . the maint. guys at work said there great
We have had good luck taking a cast iron repair rod (stickrod). beating the flux off it, and tig welding the crack or repair area with it. All the pre-heat and sand cool-down slope stuff needs to be performed also. And get some Sodium Silicate down at the drug store and load up your coolant system to make sure it won't leak. K
I have used ni-rod to weld cast iron in the past with mixed results This stuff looks like a better deal though http://www.muggyweld.com/castiron.html
Toss in a tube of Solder Seal Block Saver and from there study its habits. It might hold up for a while, but consider one of the remedies above. Bob
I'm in pretty bad shape now for welding it. Never thought the plugs would work with this damage. A big part of my using brass braze was to avoid the extended cool off period needed for Weld. Future use of this block, if any, will be limited to short runs (Three miles or less) at high throttle settings. Over a highly saline surface. Limited leakage would be acceptable. Anyway it's interesting.
anyone that has messed with 235 chevy's has seen a cracked water jacket. i have brazed up countless 235's with no problems. i would bet their is a epoxy that would work also as they have come pretty far from the JB WELD days! i remember watching 5 pieces of a freshly rebuilt 390 water jacket being brazed back together, it was in the area between the end of the block and the transmission.
Looking again at the area......if you want another stab at fixing it try to find a hunk of iron material out of another block that is similar in size and thickness.....big Mopars and Ford Y-Blocks and FE's blocks have deep skirts on them that have relatively large flat areas of iron between the webs just below the pan rail. You could cut a section out of one of those blocks and then cut out your repair area and carefully fit the new piece so it fits in juuuuuusssstt right. THEN take the block to your local furnace welding/brazing shop and have the piece furnace welded in. If you still have pin hole leaks after that then a great way to fix the problem would be to have the entire repair area spray welded to seal it up and reinforce the repair. Considering the rarity of that block its not out of the question in effort or money to try it that way. -Bigchief.
anybody ever try the Henrob torch and the cast iron welding rod/flux they sell, on a block? Only blocks I ever welded were Model T. I built a fire brick "oven" box, pushed the heat treating oven open door up to one end. Pre- and post- heat, arc welder with nickel rod. The only brazing I've done on cast iron was all non structural. Hope it works for you!
Have to keep in mind that brazing is more like gluing, than welding...i/e you're most likely not fusing the metal together, but rather sticking something over the top/in it. Good luck...I'd have never thought to braze smething like that, if it works out, I'd love to hear about it.
In the navy I was shown by our 1st class shipfitter how to braze a broken vise. About a year later it broke again,but not at the braze. [just contacted him recently he,s in his 70,s has a welding shop near san diego]
Don't Braze it--------For all cast iron projects use modern eutectic cast iron stick rod, like the previous have stated---grind to "white metal" use the V method, drill 5/16 holes at end of cracks, use a rosebud tip to evenly preheat a large area, & keep preheating as temp begins to drop off, if you are using firebricks under project, let the whole thing cool to touch before moving. Results will be good!!--------Don
Like you, I also was a metalsmith, & learned all my welding skills from my 1st class back in 1951 during the Korean war, I used those skills to join my union in 1957 & retired from there as a pipe welder in 1984 in L.A. & moved to Oregon & bought a trailer mfg. & repair business, & retired from that 5 yrs ago. Welding has been a great tool for me over the yrs. & I have passed it on to my son AND grandsons, when learned, its a thing no one can take away! I'm also 75, & still keep my hand in it!---------Don
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