anybody ever jb a block?
Senior User
Joined: Jun 2002
Posts: 423
Likes: 0
From: Oklahoma
anybody ever jb a block?
I've repaired motorcycle crankcases with JB Weld. The repair is temporary due to the constant hot-cold cycles extending the original crack. There are folks who can weld cast iron for a permanent repair.
Laughing Gas
Joined: Nov 2002
Posts: 1,198
Likes: 9
From: Fairmont
anybody ever jb a block?
I have repaired many cracked blocks with JB Weld, But first
I locate the end of the crack, then drill and pin the ends, this keeps the crack from running.
Now the pins we use are a tapered pin, then I will drill and pin the crack inbetween every 1/2 ". This prestresses the block, so now the block has a natural tendency to push together. I then "V" out a little below the surface of the cracked area,then I will take a air hammer with a pointed end and peen the cracked area and the pins. The peening probably does 90% of the sealing or more, then I will take a propane torch and heat the cracked area, just warm to the touch, NOW apply the JB weld in the "V" out,peened area. The JB weld is a little insurance. The peened area helps seal and gives the JB weld something to really hold on to. When it is dried I sand it down and paint with cast spray paint.
Simply?
I locate the end of the crack, then drill and pin the ends, this keeps the crack from running.
Now the pins we use are a tapered pin, then I will drill and pin the crack inbetween every 1/2 ". This prestresses the block, so now the block has a natural tendency to push together. I then "V" out a little below the surface of the cracked area,then I will take a air hammer with a pointed end and peen the cracked area and the pins. The peening probably does 90% of the sealing or more, then I will take a propane torch and heat the cracked area, just warm to the touch, NOW apply the JB weld in the "V" out,peened area. The JB weld is a little insurance. The peened area helps seal and gives the JB weld something to really hold on to. When it is dried I sand it down and paint with cast spray paint.
Simply?
