The factory cylinder heads are fastened to the cylinder block with factory bolts or studs. The M11 threads tapped into the block are aluminum. These threads can fail from being over torqued, pulled from high cylinder pressure, or can fatigue from the cylinder heads being removed and replaced multiple times.
Time-sert fasteners are the best option for repairing the cylinder block. Time-sert manufacturers a kit for M11 thread repairs. The repair requires the threads to be repaired with a special drill bit, tapped using a special tap, and steel inserts to be installed using a provided tool. The drilling and tapping operating is especially critical that it is done perfectly straight and in alignment to the cylinder heads. The standard Time-sert kit includes these tools, and a universal fixture plate to hold the drill bit and tap perpendicular to the block. The problem is that the threaded holes are not on-center to the cast counterbores that the fixture plate secures to. The cylinder blocks are drilled and tapped slightly off-center to the counterbores and align the cylinder heads to precision dowels. Using the universal fixture plate results in the holes being slightly off-center to the cylinder block resulting in the fasteners not being on center to the cylinder head.
To address this - ScienceofSpeed has developed a drill fixture which aligns with the cylinder head's precision dowels allowing the thread repair insert holes to be drilled and tapped in-line to the cylinder head.
This option is to rent the repair kit & fixture: ScienceofSpeed will send you the Time-sert repair kit & fixture. This option includes inserts and tooling cost. This option allows you to complete the repair and ship the kit back within 14 calendar days from the date the kits arrive. A deposit is required, which will be refunded as long as the kits are returned within 14 calendar days from the day you received the kits. Any damaged components will be deducted from the deposit as described in the instructions included with the kit.
Click here for thread repair service offered by ScienceofSpeed.
Both standard Time-serts (for factory threaded holes) and Big-sert (for previously repaired holes) are available.