Swapping an H22 engine into a 3rd generation Honda Prelude is a popular and relatively straightforward upgrade. Many enthusiasts undertake this conversion to boost performance. A key decision you’ll face early on is whether to opt for an OBD1 or OBD2 setup for your 3g Prelude H22 swap. This choice impacts various components, particularly the distributor and engine management system.
The basic mechanical aspects of the swap are quite manageable. You’ll need to swap essential mounting hardware, including the timing belt mount and transmission mount to ensure proper engine placement within the 3g Prelude chassis. For the VTEC oil pressure switch, a direct swap with the USDM version is generally recommended for simplicity and compatibility.
Creating adapter plates for the swap is also a task that can be approached with varying levels of complexity. Simple, functional adapter plates can be fabricated easily using square plates that are drilled and tapped for bolting. More elaborate, aesthetically refined plates will require additional fabrication time and effort, but the basic principle remains the same.
One common issue encountered during the 3g Prelude H22 swap revolves around idle control. Unlike some setups, the H22 in this configuration may not utilize the throttle screw for idle adjustment. This can lead to an unstable or low idle, potentially causing stalling. A temporary fix might involve adjusting the throttle cable tension, but a proper long-term solution is necessary.
To address the idle control issue and optimize engine management, two primary paths are typically considered. Firstly, utilizing Hondata engine management offers precise control over the Idle Air Control (IAC) system, allowing for fine-tuning of the idle. Alternatively, exploring an OBD2 conversion harness to adapt an OBD2A to OBD2B ECU, such as a EuroR ECU, could provide a different engine management strategy. The optimal choice often depends on individual preferences and tuning goals for the 3g Prelude H22 swap.
Beyond these specific points, remember that standard engine maintenance best practices are crucial during the swap. Replacing the timing belt, inspecting the water pump, and considering a rear main seal replacement while the engine is accessible are all highly recommended preventative measures. Addressing these basics upfront minimizes potential issues down the road and ensures the longevity of your 3g Prelude H22 swap project.
