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These instructions will show you, step by step, how to install the HPI #1703 Heatsink Cooling Head on your Nitro Star 15FE. Using this option part on your engine is a way to enhance the performance of your engine by reducing its operating temperature, which will help it last longer between rebuilds. For instructions how to rebuild your engine (meaning to replace the piston and sleeve), see the main Rebuild Your Engine walkthrough or download the PDF here.

The instructions below are specifically for the Nitro Star 15FE engine, however the process of removing the head of other types of engines is the same.

First, we start with taking the engine out of your car or truck. It is beyond the scope of these instructions to show you how to remove the engine and anything attached to it - see the Instructions Page for your kit for details.

The next step is gathering the required tools - for the 15FE, the only tool you will need (beyond removing the engine) is a #2 Philips screwdrivers (with hardened tip). Because the #1703 head includes 2mm hex screws, you may want to have a 2mm hex wrench available also. The #1703 set includes a standard L-wrench, but use a high-quality hex wrench if possible.

Other engines may require a different tool, like a #1 Philips screwdriver or 2mm hex wrench. Be certain you are using the correct size screwdriver or wrench, or else the tool or screw may be damaged and you could be forced to drill out one or more of the head screws just to take the head off.

Using the proper tool, remove the screws holding the head in place.

Keep the engine head in a spare parts box, just in case you may need it in the future. If you are certain you'll never need it again, you can through it away. Throw away the head shim also, you won't need it with the new head.

This is what the #1703 head looks like. The 2mm hex screws resist stripping and the new head shim should be used when installing the new head.

Make sure there is no dirt or grit on the bottom of the new purple cooling head and install the new head shim in place on the bottom of the head.

Put the new heatsink head in place as shown below - this helps prevent the shim from falling off the head.

Now is the time to note how your engine is located in your car or truck kit.

If you have an HPI car or 2WD truck, the heatsink head should go in place as shown below. This lets the air flow through the head and maximize cooling.

If you have a shaft-drive HPI kit, the heatsink head should go in place as shown below.

Use the hex wrench to install the screws. When you start to feel resistance (the screw head is near the bottom), STOP turning the screw. Repeat this for each screw.

This is where you must use the "star" technique to finish tightening the screws. Use the picture below to guide you. You must NOT tighten the screws going clockwise or counterclockwise around the engine head. You MUST use the same technique that is used to tighten wheel nuts on a full-size car. In the example below, we start at the top left, then the bottom right screw, then top right, and finally bottom left. This makes sure that the pressure holding the head on is near equal for all the screws, and the head is on flat against the sleeve.

Now you are finished! The next time you start your engine, let it warm up and check the adjustments of the carb - with the lower operating temperatures you may have to re-tune the engine slightly.

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