Honda K20/K24 to RX8 adaptor plate

This adaptor plate will allow you to fit a 2004-2008 Mazda RX8 5 or 6 speed gearbox behind your Honda K20 or K24 Engine and mount it upright in the engine bay.

The plate is laser cut to ensure accuracy and repeatability so all adaptor plates are manufactured and fit the same.

The top two countersunk holes are used to align the centre line of the adaptor plate to the centre line of the crankshaft. The plate is supplied with the two countersunk M10 screws for this as the thread in Honda block is fine pitch. There are 2 dowels welded into the adaptor plate that then line the gearbox to the crank centreline that are tapped to accept fixings.

The conversion kit comes with 2 spigot bearings for the rear of the crank.

Your gearbox will need notching slightly to clear the nose of the starter you are using. This can be done by bolting the adaptor plate to the engine and then the gearbox to the plate, offering up the starter and seeing how much material needs to be removed.

*When using this adaptor plate you will need to machine 15mm from the RX8 bell housing and then re-counterbore the holes in it for the dowels. We can offer this machining service at a cost of £75.*

With this adaptor plate on a K series you need the following, starter clutch and flywheel setup:

• Civic Type R flat flywheel and pressure plate with a 215mm 1"x23 spline friction plate. This can come from a 2.0 MX5 or use a Ford one.
• Standard K20 starter to match the flywheel

This setup can be used with the standard external slave cylinder, one of our cable clutch conversion kits or one of our hydraulic concentric release kits. With the concentric kit please get in touch before ordering to confirm clutch height. Please get in touch before ordering the hydraulic concentric release kit to confirm your clutch height.

If running the standard external slave cylinder, some webbing will need removing from the engine or a spacer is required to move the slave cylinder back away from the block.

When using this setup with the cable clutch you will need the 20mm spacer for the release bearing.

Click here for the cable clutch conversion kit to suit this setup: 5 Speed or 6 Speed