Waterproofing a Land Rover V8 (that is keeping the thing running when crossing water that is over the bonnet) has always been a problem.

A few years ago I invested in a set of Magnecore HT leads that revolutionised my own deep wading capability with the Range Rover but the distributor has always been a weak point. After wading, condensation and steam build up inside the distributor cap causing a misfire and eventually stopping the engine. I've tried pressurising the distributor, sealing it etc.... but all to no avail.

The solution was obviously easy - get rid of the distributor. I could do this by fitting a diseasal and putting up with that tractor noise from under the bonnet and a chronic lack of throttle response OR build a distributorless ignition system.

At first I had intended to build and design my own system until someone sent me a link to the Megasquirt site... at which point I got all excited about the prospect of having a single cheap ECU that would control both ignition and injection. This little box of tricks would replace the current hotwire injection system and allow me to stick the vehicle on a rolling road and adjust fuelling and ignition maps in real time...

The ignition system itself is based on a Ford EDIS (Electronic Distributorless Ignition System) which uses a sensor to detect the crankshaft position and drives the four ignition coils directly. This is a self contained system that provides a pulse signal to the Megasquirt ECU and will fire at 10 degrees BTDC unless Megasquirt tells it otherwise.

This system is now fully operational on my 100 inch and has already provided improved power and response over the original setup. I will be organising a session on a 4wd rolling road sometime soon to tune in two maps - one for economy and one for competition use. A switch on the dashboard will change between the two. So far all the tuning I've done has been done on the road by logging the engine data on a short but varied run then making adjustments to the fuelling map before repeating the run.

Recent testing has shown that the ignition is quite happy running submerged although a problem with the cold idle did cause the engine to stall - the water was so cold (we had to break the ice in parts) that with the engine immersed in near freezing water the engine temperature dropped rapidly triggering the cold start enrichment function in the ECU. I was too late to catch it by increasing the revs and the engine stalled. As the exhaust manifold was still under water at one side I couldn't risk restarting it so had to be pulled out of the water where it fired up first time. A second test, where I kept the revs up a bit, saw the water up over the bonnet with the vehicle stationary (no bow wave to artificially lower the water level) for a period of time and the engine never missed a beat.

I will get the cold idle fuel mixture sorted before I try this again ! Still at least it was Paul's seat that got wet rather than mine...