Here’s the final update on the Mini 1275GT CR14DE engine conversion:
Over the winter it’s had a new Minispares alloy radiator, the engine’s been moved forward 5mm as it was too close to the subframe tower on the driver’s side and a softer lower engine mount made to clear some of the harsh vibration coming into the cabin. The gearchange has been moved back about 25mm – it’s now right up to the cross-member. This makes it a little more comfortable to use and the bend in the gear change cables is a little less severe, so the gears now snick up & down as you would expect from a Nissan. There’s a modified instrument panel with a new 3-D printed tachometer and a couple of OLED displays to provide a graphical display of engine temp, fuel level and air-fuel-ratio plus some other details from the ECU. The exhaust pipe has been heat insulated where it passes close to the gear change cables.
The throttle opening has been reduced to around 75% of maximum and the pedal throw made a bit longer. This gives a more progressive throttle and is a bit less brutal in 1st & 2nd gear. With extra sound deadening and carpets in place the car is a bit more civilised overall. There’s 10mm wheel spacers on the front wheels to help avoid the clash between the front tyre and the repositioned tie bars. I’ve still lost some lock but now it’s not much of an issue – just need to avoid forcing the wheel near extreme lock.
The wiring has been tidied up in the engine bay (believe it or not!) and a 3D printed oil separator has been added between the crankcase vent and the throttle body.
Here’s the revised instruments:
I invested in a 3D printer mainly to make some replacement parts around the house but also to make some of the more intricate custom car parts that are too difficult to make conventionally. Here’s the Mini’s tachometer, modelled in the excellent DesignSpark Mechanical (free download from Radio Spares!). It is driven by a small RC servo (SG90) that needed to be geared up by 1.5:1 to provide ~220 degrees throw. There’s an Arduino 2560 mounted behind the instrument panel that drives the OLED displays and also provides a PWM signal to drive the tacho servo.
This was “sliced” with Cura and a kit of parts printed on a Creality Ender 3. The bezel was given a coat of satin black prior to assembly:
The oil separator was designed in 5 parts with the top, inlet & oulet tubes and the base permanently bonded together. A separate oil can screws into the base. This is intended to trap any heavy oil droplets coming out of the engine and seems to be doing its job, so far:
UPDATE August 2019
The 3D printed oil separator worked fine in town driving, collecting about a half-teaspoon of oil in around 600 miles. However, after an 80 mile motorway journey this happened:
Clearly, the sustained fast driving had produced hotter engine gasses that softened the plastic and the high vacuum caused it to collapse. Note for the future – keep PLA plastic away from hot engines! So had to invest in a metal one: