Calvan 39300 3V Spark Plug Thread Repair Components

DennisB WiseAutoTools.com © Summary: Parts and tooling that’s included in the Calvan 39300 or ATD-5410 3V spark plug thread repair kit for M16x1.5 3-Valve engines and basics on how it’s used to restore spark plug threads without removing the cylinder head. The ATD-5410 is a 3V spark plug thread repair kit that repairs damaged aluminum spark plug threads for Ford 3V engines. The ATD5410 is made by Horizon Tools, which also markets the same kit under different labels, including Calvan, OEM, Mountain, Mac, CTA, Snap On, Cornwell, Matco and others. It’s important to make sure the valves are closed before doing any work. An optional 389-4000 cylinder leak tool can be purchased separately. The tool has a rubber stopper attached to a hose and brass needle valve. Air from a compressor is used by attaching a coupler to the male nipple on the leak tester and turning the valve on, with the rubber cone in the spark plug well, this allows a small amount of air to enter the cylinder being worked on. Once the valves are closed the stopper (or rubber cone) will pop out.

By turning the engine over slowly with a 1/2″ ratchet on the front crank bolt, you’ll find that once the valves are closed for the particular cylinder being worked on, the stopper will pop out. Rechecking can be done just to make sure the engine’s crank was not turned too much opening the valves again. Once satisfied that the valves are closed on the cylinder being worked on and the piston is down far enough out of the way as to not be damaged by tooling, work can begin. Reaming is the next step. The kit consists of tooling that is used to ream or drill the spark plug port out using a guide to insure that it is done straight every-time even in tight areas like near the cab. 

The E-clip makes sure that the drilling is done at a proper depth, NOT damaging the seat inside the cylinder head where the spark plug meets the head to seal compression. Then the thread tap cuts threads into the spark plug hole which will accept the new steel alloy insert. The steel alloy insert shares enough of the same properties as the aluminum that there’s no issues with expansion, contraction or grounding issues. In fact on the older 2V engines a similar kit and inserts have been tested by time with no issues. The insert is installed using the installer tool along with JB Weld or high temp permanent lock-tight sealer. Unlike the 2V version of this kit, the spark plug is to be installed with the installer rather than just the spark plug and an extension. This is because the installer has a stop that prevents traveling too far in the insert like the spark plug could do if it were to be used to install the insert. On the 2V version of the kit, there’s no risk of this because the seat is built-into the 2V insert which acts as a stop. Below is a detailed list of the components in the ATD-5410 kit.

Part Number QTY Item

ATD-5412 8 Inserts Also known as 393-100’s.

393-400 1 3V Guide

389-200 1 Reamer, also known as core drill. Can also be used for 2v Horizon spark plug kits.

393-300 1 Thread tap. Can also be used for 2V Horizon spark plug kits.

393-200 1 Insert Plug. Used to install the insert, as mentioned above it has a built-in stop.

393-300 1 Replacement blow molded case.

Optional 389-4000 Cylinder Leak Tester. Not included in the 3V kit but in our opinion – it SHOULD BE!

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