Winter Prep
Hi, its James here with the latest update from the Mighty Minis race series. Hopefully you enjoyed the introduction and now I would like to share with you what the drivers are getting up to during the winter preparation season.
Most drivers are currently upgrading their cars to the new 2025 regulations. Dad and I would need to remove our engines from both cars to get them upgraded. I first set about removing the engine from Dad’s car. This required half a day’s work to undo and disassemble the engine bay, luckily the engine came out easily! This exposed the engine bay and some damage from the last race meeting. Dad loves a bit of body repair, so he set straight to work with his hammer and dolly. We would be sending the engines to Neil Slark, at Slark Race Engineering, for him to undertake the machining work. He required them to be completely stripped down, this is to save him time and me money! I have to say this is quite an enjoyable job, being careful to keep all items removed together and all the nuts and bolts labelled.
Once dad’s engine was out I started on my engine by draining the fluids and then gradually removing all the ancillary items from the engine. Once complete it was time to lift the engine out. Luckily, I have the use of a ramp, thanks for letting me borrow this Uncle Chris. It makes this job a lot easier, no need to worry about axle stands and crawling under the car. I positioned the engine crane in place and began the lift, dad assisted, and the engine was removed quite quickly.
Looking at the engine and gearbox I could see the distributor seal had been leaking, not ideal but it probably looked worse than it was. I then proceeded to remove the clutch/flywheel cover to reveal a worn-out clutch release bearing and some oil on the flywheel. This could have contributed to my suspected clutch slip, however there was also an issue with the slave cylinder. The slave cylinder return spring, and lever had come out of position and the spring had been rubbing on the cylinder itself for what looked like quite a long time. Although the clutch was working it clearly hadn’t been working as efficiently as it should have been. With all the ancillary items removed I could get it all packed up for sending to Neil. Thanks goes to dad for building a crate to put all the items in. All wrapped in bubble wrap and secured they were ready for collection.
The new parts we will be using for the upgrades will obviously be from Minispares. The new pistons are the Minispares EVO variant and these are sold in conjunction with the NPR rings (C-STN105-20). These have been run in some of the Mini 7 S-class engines for quite a while and are an ideal, low-cost piston, for the race cars. To accompany these pistons the camshafts have been changed to the AC Dodd Track Sport/Rally Camshaft (ACD-TSR). Once again these have been tried and tested in the Super Mighty Minis for many years and will give the Mighty’s an extra 10 bhp increase, exciting stuff for the race cars! Further engine changes include the inlet valves which will have triple cut valve seats using the 35.7mm long stem race valve (C-AEG544). This will also add to the increased bhp of the Mighty Minis. These are the main and most significant changes to the engine specification.
With the gearboxes you have two options. If you opt to stay with the 1275cc capacity engine you can run either straight cut or stand helical gears with the 3.9:1 differential. However, if you opt for the 1293cc engine spec you must change to a 3.6:1 differential. We are upgrading to 1293cc and have opted for the Clubman Straight Cut gear set evolution A plus type (C-STN39). Once again these have been tried and tested in the Super Mighty Minis and have not resulted in any issues. As I’m sure some of you will know the 3.6 differential is derived from the MG metro, these can be purchased from Guess works.
Once the machined engine parts return from Neil I will be building the engines and gearboxes with the help of my uncle, Chris Ashton of Ashton Autos. This will be the first time we have built our own engines, so I am looking forward to the challenge and also the satisfaction knowing our race cars are fully home built!
Hopefully this gives you a more detailed insight into the changes for the 2025 Mighty Minis season. It is set to be a fantastic season of racing, close and affordable at some iconic British Tracks. I will update next month with some more insights into car preparation.
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