History of the NS300L™ insert system
Thank you for your interest in the NS300L™ head bolt thread repair system. In 2005 I had purchased a pre-owned 1996 SLS Cadillac with a 4.6l Northstar. Shortly afterwards, I started having problems with it overheating, due to what I thought was a blown head gasket. I then realized it had been repaired once before with GM-approved solid synchronized inserts which pulled out with very little torque applied. After doing some research, I found that the Cadillac Northstar 4.6/4.0L engines were notorious for this problem, and a larger diameter GM-approved "second repair" insert was available. The challenge with the second repair was, it also had the same fine threads as the failed GM-approved "first repair" inserts. The last thing that I wanted to do was to install another fine thread insert, because if they failed, I would have had no other option but to replace the engine block. After doing much research, I realized there were no reliable options on the market.
My background is in the Tool and Die/Machinist trade. Having 30+ years experience in the trade and a knowledge of the types of thread inserts used in the aerospace & defense industry, I developed the NS300L™ Insert System. The NS300L™ Insert System is a head bolt thread repair system engineered to outperform all other kits on the market for aluminum engine blocks. Unlike thin inserts with synchronized internal and external fine threads such as the GM repair, the NS300L™ insert is designed to be a far stronger insert due to its longer length, bigger diameter, and coarser external thread for maximum strength. This prevents the insert from expanding under high torque, and allows the load to be distributed to a much larger area. As a result, the load per thread is much less, significantly reducing the chance of cracking the block. Our standard M11x1.5x44.45mm insert has over three times the thread engagement within the aluminum block than the GM-approved first repair insert, over two times that of the GM-approved second repair insert, and almost four times that of the common standard coil type inserts. There is nothing wrong with those other type inserts, they are very well designed inserts for many applications. The challenge with them is, they do not always get past the deteriorated aluminum and back into virgin aluminum due to their smaller diameter and fine external threads (the same fine threads as the head bolt that failed in the first place), and have a tendency to pull out during the head bolt tightening process. Occasionally, those other types of inserts have failed only a few hundred miles after the repair. We have had several technicians contact us with this challenge. They found the NS300L™ insert gives them a much stronger, more reliable repair, and in return, saves them the expense and frustration of failed repairs. One dealership informed us that they had stopped repairing Northstars with stripped head bolts on engines having over 100K miles, due to the high number of failed repairs with the GM-approved inserts. They felt the NS300L™ Insert System would be the answer to this challenge, and they have been very pleased with the results. A Toyota dealership informed us that due to the high number of failed repairs using their "approved" repair which is the exact same insert as the GM "approved" repair, their insurance adjuster told them to stop using their "approved" repair and to start using the NS300L™ repair system. We receive positive feed back on a regular basis from Cadillac, Toyota/Scion, Honda, BMW, Subaru, jaguar, Chrysler, Hyunda, Kia and other technicians, about how impressed they are with the quality, strength and ease of installation of the NS300L™ Inserts System. In fact, the NS300L™ Insert System is now the thread repair system of choice for many general automotive tech's, automotive machine shops, hot rodders and custom engine builders.