Engine Block Repair
Most cast iron engine block repairs are done using metal stitching or pinning. Welding an engine block can be difficult due to high temperatures and special procedures implemented by professional welders. This is a task typically performed by a professional welder or someone with the appropriate skill set. This is because this is considered a relatively difficult task and there are often easier and safer ways to repair cracks in iron engine blocks. If the crack is repairable pinning is a simple and effective way to repair iron engine blocks.
Use pinning to repair both small and large cracks in cast iron cylinder heads and blocks. These pinning kits use a bolt of the same material as the head or block being repaired. This is typically iron. Here's how:
1. Always start at the ends of the crack. Take a punch and peen the crack or the ends for longer ones.
2. Drill a hole at one of the ends using the size bit that matches up with the bolt. These cracks usually reach all the way into a coolant or oil jacket. Be sure to drill deep enough to repair this leak.
3. I like to ream a ridge around the bolt hole before inserting the bolt. These pinning kits will have the proper tap but if not just match a tap from your set to the bolt and tap the hole created in step two.
4. Apply the thread lock or sealer provided in the kit and torque the bolt to around 50lbs.
5. Grind or cut the bolt close to the surface and then peen the bolt again with a punch and hammer.
6. Smooth the bolt even with the surface.
Engine pinning is done using a drill, tap, bolt, and a grinder. Some kits include a glue or epoxy to finish the bond. This method draws the two sides together creating an almost undetectable repair.
If the crack is easy to get to like on the front of a head it may only take a few minutes. Welding a block can exasperate the situation and is usually used for holes not cracks in the block anyway. Welding is an excepted form of repair but as mentioned earlier left for a professional welder.
