How Best To Repair Cracked Outer Wall

11secAvanti · Post by **11secAvanti** » Sat Mar 26, 2005 9:47 pm

I cleaned a V-8 block today for later use and found a hairline crack about 3.5 inches long on the outside wall about 1 inch above the center freeze plug. All cylinder walls though are fine. It is just the outside wall. What is the best repair, welding or block sealer? If sealer, what is highly recommended? Should it be sealed externally like JB Weld or by a coolant additive? Thanks for the help.

bill jones · Post by **bill jones** » Sat Mar 26, 2005 10:40 pm

-Is this on the Studebaker block?
-Does the crack go into the freeze plug hole or is it just a crack an inch long that goes nowhere?
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-Regardless, you need to stop the crack and that means you have to find the absolute end/s of the crack and drill a hole/s so that the crack stops within the hole/s.
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-I would probably use the cast iron tapered pins that are used for crack repairs of this nature by drilling and interlocking them.
-it would only take about 6 or 8 pins to do one inch of length, but you might have to buy a kit with 100 plugs and the special tapered tap.
-Or maybe you could just use two larger pipe plugs and interlock them.
-A lot depends on what is behind the crack inside the water jacket.
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-I have done several repairs like this where I just brazed the cracks, so if you are interested in the brazing procedure I can explain that.
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-I would lean towards a mechanical fix rather than attempt a chemical fix.

11secAvanti · Post by **11secAvanti** » Sun Mar 27, 2005 12:06 pm

The crack does not go into the freeze plug area. Yes it is a Studebaker V-8. I was preparing it for a short block race backup. The crack itself is a good 3-4 inches long and runs parallel to the block horizonitally. It is fairly straight and not a vertical run. It is located 1 inch above the center freeze plug hole. Accessiblity is very easy. The block is cast iron and I am told these blocks have some nickel content but basically a cast iron block. By brazen do you mean cast welding? I may be able to find a cast iron welder. Are these pen kits something that Napa has? I too lean toward welding at this point. Thank you for the response and guidance on lthis issue.

bill jones · Post by **bill jones** » Sun Mar 27, 2005 1:14 pm

-I do NOT care for cast iron welding of the block, but instead I would braze the crack.
-That needs to be done by somebody who KNOWS what they are doing.
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-When blocks are cast iron welded they heat the block so bad that the block comes back red in color and I don't like it one bit.
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-To braze the crack I drill a hole 3/16" hole at each end of the crack, then I use a 3/8" diameter carbide burr ball and I dig out a trough the full length of the crack until theres a 1/8" gap at the bottom of the trough.
-Then I take a 1/8" ball burr and cut thru that gap and try to clean up the water jacket side slightly.
-Then with two people and two torches, you preheat the block for a short time and then you concentrate one torch on the side you intend to braze and use the other torch to braze the trough.
-I use 300 and a 350 degree F temperature crayons and when the block is 350 degrees several inches inches away from the wound and 300 degrees say 6" from the wound I start to braze.
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-I start at one end of the trough and braze it a short distant, back off for a moment and wave the other torch around to spread the heat out, then I'll start at the other end and braze it a short distance, and do this same procedure several times until the wound is filled.
-I don't like to braze more than about half an inch at a time because you end up with too much concentrated heat at the wound.
-I like to back off momentarily and let that heat spread out with some help from the second torch.
-Then when you have trough filled and finished you have to back down on the heat but continue to apply some declining heat thruout the block for maybe another 10 minutes and then cover the block with blanket to hold what heat you have in there.
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-I also use an air hammer with air pressure regulated down and I'd either use a needle descaler tool or I have a chisel end that I have prepared that has some teeth, that I use to lightly air hammer or peen the wound and out and away from the wound as the cast iron is cooling off, lightly working this air hammer during the 10 minutes of declining heat, maybe even until I could almost touch the block without getting seriously burned.
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-I have done several blocks this way and none have cracked during the cool down process and none have leaked water.
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-the tapered plugs:
-K-Line (1-800-528-9238) has the plugs in 5 sizes from .155" to .386" for boxes of 100 for the smaller plugs and boxes of 50 for the two larger sizes at a cost of about $60 a box.
-I'd choose plug part number KL3908 ($61.13 for 100) which is .235" at the small end and it's a half inch long.
-The corresponding tapered reamer is part #KL3925 ($62.08) and the corrsponding tapered tap is part #KL3931 ($46.91) and there's a drill part #KL3916 ($4.53)
-You'd use about 15 plugs do a 3" long crack.

Wolfplace · Post by **Wolfplace** » Sun Mar 27, 2005 2:00 pm

Here is another type of pinning that I feel is a better option.
http://locknstitch.com/
Check out their site. They have both straight threaded pins with a top that breaks off & leaves no threads at the surface that I feel are much better than the old "Irontite" taper ones & also a "hooked" thread pin that actually pulls the crack together rather than applying a spreading force.
Also have some "locks that tie the crack together, excellent spark plug repair inserts etc.
Lots or real good info on the site too

11secAvanti · Post by **11secAvanti** » Sun Mar 27, 2005 9:06 pm

The tapered pin and plug procedure seems the way to go. Crack block redemption is now possible. Thank you for the feedback on this method of crack repair.

Oldhemidude · Post by **Oldhemidude** » Mon Mar 28, 2005 10:47 pm

There is a guy on the Eastern shore of MD that has been stiching blocks for 40 plus years and has no problems, if you want to take to some one. English's Auto 410-754-5350

11secAvanti · Post by **11secAvanti** » Mon Mar 28, 2005 10:50 pm

Thanks again, I appreciate the tip lead.