Carl Fausett
24th February 2010, 16:24
We have a new process to repair stripped-out threads in 928 blocks.
Some 928 engines are "junked" only because of a stripped head stud or head bolt. These engines can be repaired and put back into service.
Our thread repair is the correct length to fully engage all the threads in the head stud as designed. Other thread inserts shown in the photo below are too short, and apply all the load to a lesser number of engagements with the block, and that's why they fail and pull out.
Further, our thread insert uses a buttress-thread between the insert and the block, so as not to exert any outward forces upon the casting. The shape of common thread inserts is beveled, and pushes outward on the block as the stud is drawn up. This can cause cracking of the block, and failure of the insert. For this reason, our insert repair process actually strengthens the block, instead of weakening it like others do.
These have been inserted and tested and shown to hold full factory head stud torque as well or better than an undamaged stud.
A 928 bare block in a heavy cardboard box with padding will weigh about 100 pounds, and they ship via UPS ground. Turn-around time is about 1 week on this repair.
Some 928 engines are "junked" only because of a stripped head stud or head bolt. These engines can be repaired and put back into service.
Our thread repair is the correct length to fully engage all the threads in the head stud as designed. Other thread inserts shown in the photo below are too short, and apply all the load to a lesser number of engagements with the block, and that's why they fail and pull out.
Further, our thread insert uses a buttress-thread between the insert and the block, so as not to exert any outward forces upon the casting. The shape of common thread inserts is beveled, and pushes outward on the block as the stud is drawn up. This can cause cracking of the block, and failure of the insert. For this reason, our insert repair process actually strengthens the block, instead of weakening it like others do.
These have been inserted and tested and shown to hold full factory head stud torque as well or better than an undamaged stud.
A 928 bare block in a heavy cardboard box with padding will weigh about 100 pounds, and they ship via UPS ground. Turn-around time is about 1 week on this repair.