DennisB DenLorsTools.com © Summary: Head bolt thread repair kits for repairing headbolt threads in the cylinder block are covered by a master automotive technician. Advantages of using Time Sert 11125 over the Helicoil 5543-11. Both kits are for M11x1.25 head bolts which are commonly found in Subaru and Nissan (and Infiniti) engines. Which is better? What causes failure of the threads? These questions and more answered below. Also see the video discussing differences in Helicoil VS Time Sert. Click the following current pricing on the Time Sert 11125. For over-size see Time Sert 11125BS. See below for more information.

With the use of aluminum in engines in modern automobiles and since aluminum is softer compared to other metals; threads failing is a more common occurrence today compared to older generations of automobiles. Aluminum parts like engine blocks, cylinder heads, intake manifolds and oil pans are used to reduce the overall weight of cars and trucks which help to increase fuel mileage. Manufacturers are even using more aluminum body parts for the same reason. This helps to increase gas mileage by lightening the load. Aluminum used for engine components have many benefits. It’s lightweight, easy to form and machine which makes the manufacturing process faster and less expensive. Simply put, one drawback is that aluminum is not as strong as steel. This is particularly true with engine components because of thermal cycling. Thermal cycling just means heating and cooling over and over. This can cause problems. Especially with crucial threads for holding spark plugs in and head bolts clamping down heads to blocks. Modern cars which are obviously computer controlled, are designed to run at higher temperatures than past generations of non-computerized vehicles. The higher running temperatures, help to atomize fuel better which makes cars more efficient. However, higher temperatures are even more stressful on threads that hold engines together. Head bolts are designed to stretch in order to maintain proper clamping force. These bolts are called TTY (Torque to Yield). Read an article we did awhile back for more details on TTY head bolts. Below are some frequently asked questions that apply to aluminum thread repair.

TIME-SERT 11125 FAQ’s

Question – What causes head bolt threads in the cylinder block to fail?

Answer – As mentioned above, head bolt threads in blocks are aluminum and have to survive many cycles of heating and cooling. Over time, even with proper torque the threads can deteriorate and cause the threads to fail. Aluminum is weaker than steel so it’s no wonder which threads are the weakest link. Sometimes a coolant leak can lead to overheating which can in turn cause the head gasket and then the head bolt threads to fail because of extreme temperatures. Other times the threads could fail first resulting in head gasket failure. Either way, using Time Sert carbon steel inserts will help insure a lasting repair. After all steel is stronger than aluminum.

Question – I’ve heard about Helicoil but have never heard of Time Sert. Which thread repair is better?

Answer – Helicoil is the best known brand of thread repair. However, Time Sert has many advantages over Helicoil, especially when it comes to aluminum thread repair. Below is what Time Sert says about the advantages of Time Sert solid inserts over thin coils like Helicoil.

TIME-SERT® is a thin wall, solid bushing, self locking insert with positive placement.

TIME-SERT® inserts are a thin wall solid bushing insert. This guarantees easy installation and allows for full load use of tapped hole, ensuring protection against stress and vibration.
TIME-SERT® inserts are “timed” internal to external which gives a very thin wall thickness which means TIME-SERT inserts can be installed in areas of limited space and clearance.
TIME-SERT® being a solid bushing insert gives it added strength, easily withstands high temperatures without damage or deforming. TIME-SERT® inserts have no prongs or tangs to break off or deal with down in the hole, which can be a problem in deep holes.

TIME-SERT® inserts are self-locking having an actual locking feature which will prevent them from coming out when a bolt is removed. On installation the bottom few internal threads of the insert are cold rolled to expand into the mating external threads of the base material locking the insert in place.

TIME-SERT® inserts have a flange, which will give them a positive placement on installation for accurate specific depths. This ensures that the insert does not wind down into the threaded hole.

Thin wall, self locking , solid bushing insert with positive placement.

Customers have asked if they may also use Loctite® adhesives for additional strength. Yes you may due to the solid wall design. There is no danger of loctite passing thru the threads of the insert and locking up the bolt as in coil types. Time-Sert inserts are used in Aluminum, cast iron, steels and even some hard plastics. MADE IN THE USA.

Question – I purchased a Helicoil 5543-11 kit from a local parts store, but it’s not long enough to reach the threaded part down in the block for my Subaru. Is Time Sert 11125 tooling long enough to reach the threads?

Answer – Yes. The Time Sert kit comes with tooling that is longer and capable of repairing threads that are not near the surface. In fact the tooling in the 11125 kit can be used for any M11x1.25 head bolt application because it is universal. Tooling is marked after measuring the depth of the holes with the supplied marker and and metal ruler. *Some holes may be deeper than others even on the same engine so each hole should be measured to ensure proper drilling and insert installation preparation work.

Question – I already have drill bits. I just want the tap and the insert. Will just sell me just the tap and an insert?

Answer – We don’t sell just pieces of a kit, unless our customer needs replacement parts for a kit previously purchased. The reason is because we don’t want to set you up for failure. There’s actually a reason for every piece in the kit. For instance the core drill bit is not a “regular” drill bit. It has a stepped design and has a counter-sink built in so that the insert sits flush. The line-up bushing along with the drill fixture plate helps insure that drilling is done straight. The installation driver finishes cold rolling the insert and expanding it at the bottom holding it in place. The permanent, high temp red loctite also aids in making this a permanent repair.

Question – After a Helicoil fails can I use the 11125 kit?

Answer  – No. The Time Sert 11125 kit is a “first time” repair. Meaning no other repair like Helicoil or competitive brand has been used. The Big Sert kit can be used, pn 11125BS. It’s inserts are a larger outside diameter and still accepts the same size M11x1.25 head bolt.

Question – I have a 11125 kit and just need one Big Sert. Can I install Big Serts with my regular size 11125 kit?

Answer – No. Since the Big Sert has a larger outside diameter, the tooling is different. For this reason the Big Sert 11125BS kit will be needed.

Remember we are master tech owned and are an authorized stocking Time-Sert distributor which only sells on DenLorsTools.com and WiseAutoTools.com. We offer fast shipping for free! And discounts over the phone when choosing slower shipping methods 800-524-9783.