Q: I am working on a Ford V-10 engine and have drilled one stud off center near the threads of the head and broke a screw extractor off in another one. I have been working on this repair for two days and don’t see an end soon. I am thinking my only option is pulling the cylinder head and sending it to a machine shop to rescue me. What suggestions do you have?
A: This is the most common call our technical support team receives. A challenging repair becomes increasingly challenging due to an honest attempt, unfortunately without the right tool. To remedy, let’s first understand what may have caused the extractor to fracture. Naturally, the torque requirements of the extractor were exceeded. But what we have found when studying hundreds of repairs is that the burr caused under tensioning the stud to break, turns the threads of the stud into a lock washer, lodging the remnant into the head. Second, the corrosion inside the tapped hole caused when the piece of the stud broke off leaving fresh aluminum exposed to unburned chemicals in the exhaust. This accelerates corrosion and it becomes crusty and physically blocks the threads. These two cases aggravate the repair time and increase the stress on the extractor to fracture.
We recently introduced a newer version of our ever popular Rocky tool, now the “D” model version. This new device features removable and interchangeable drill bushings that allow larger stepped drilling for more challenging repairs – especially the V-10 engine. To remedy this condition, simply bolt the new version in place and select the medium size bushing. Use a matching carbide bit and machine the extractor out of the head. Step to the next large size and remove all remaining fragments of the stud and follow with a high quality thread chaser. Follow this approach for the other stud as well.
Information provided by: ProMaxx Tools
