2024 Overview - Hillclimb Car

Following the last mapping session in 2023, the hillclimb car remained untouched since the last mapping session at the SCM remaps rolling road in Cross Hands. The first event of the year was the Isle of Man hillclimbs, a great event organised by Longton and district car club which consist of three closed road events over three days. All seemed well in the initial drive to the first event, with no untoward signs from the car, except for a small cloud of white smoke when using launch control on the start line during the first event. Following the first practice runs, all seemed to be well, which meant it was time to turn up the boost! During a fast 5th gear section on the second timed run, however, the car's oil protection limiter was deployed and the engine started to rattle and run on 3 cylinders. Having barely made it to the top of the hill, suspicions arose that this wasn't a simple issue, despite some kind reasurances from one of the other competitors.

A spark plug was removed from cylinder number 1, which had a missing chip from the ceramic base. It was concluded that the best plan of action was to abandon the event and to return to base to investigate. A few weeks later, the engine was disassembled to see the cause of the chaos. It seemed that the liner in cylinder 1 had split, which subsequently caused piston 1 to jam in the bore. The rest of the engine had kept on moving, which ripped the skirt of piston 1 and put a large amount of swarf in the sump. This had also caused the valves from cylinder 1 to impact the piston, which bent the valves and damaged the cylinder head. Sadly the only thing which could be salvaged from the engine was both cam covers!

So the next decision arose - with the engine unusable, which route were we going to choose for the rebuild? As you might know, there are a multitude of commonly used Subaru engine combinations, from the 2.0, 2.1, 2.35, 2.5, 2.6, and a 2.8! We decided to stick to the 2.5 as we were very happy with how the 2.5 was able to spool the big Xona Rotor turbo. It was then time to source new blocks, heads, and all the engine internals for the rebuild. Happily, Steve from Roland Alsop Machining was able to advise us on which parts to choose and the required machining. His help was greatly appreciated and was a big learning opportunity to learn what was required to ensure reliability for high power Subaru engines. Fast forward 6 months and we had gathered together all the required parts, including a beautifully machined EJ25 closed deck block, ready for the rebuild. Assembling the engine was a painstaking process, as with every engine build, it was vital to ensure that the engine internals were clean, and that parts were installed correctly.

After double checking that all the ancillaries were bolted on to the engine, and that all water and oil pipes were tight, it was time to prime the oil pump and to start the engine! Much to our relief, the EJ25 was prompt to start, and sounded healthy, with the Link G4X keeping an eye on the oil pressure and coolant temperature.

It was then time to run in the engine over a thousand miles, and to get the car ready for the 2025 hilcllimbing and sprinting season!