One of our members sent these over last week and I wanted to get them up on the blog. They built the 42172 McLaren P1 from first bag to final panel, all 17 photos, and you can tell straight away they know the real car. The yellow is spot on for the P1 signature colour and they even propped the set’s printed McLaren P1 spec plaque in front of the finished build for the last shots. That is a proper build diary and it deserved a proper post.
LEGO Technic McLaren P1
The 42172 is LEGO Technic’s take on the McLaren P1, the hybrid hypercar McLaren built in a limited run of 375. The set captures the key visual details (those butterfly doors, the active rear wing, the sculpted yellow bodywork) and packs in working functions that give you a feel for what the real car’s engineers had to solve.
Under the body you get a V8 engine with moving pistons, a 7-speed gearbox you shift with the paddles either side of the steering wheel, a rear wing you raise with a gear under the tail, and those signature dihedral doors that open upward. The front bonnet opens too, on a stay, over a small front boot. It is a satisfying kit to display with everything open.
What to expect when you build it
The early part of the build is all drivetrain. The gearbox comes first, a dense gear cluster with two orange shifter drums that has to be right before any bodywork goes near it, and the V8 block then sits on top of it. The 7-speed box is worked from the paddles either side of the steering wheel, which go in later. Getting those connections to click cleanly takes patience, but it is worth it.
The rear wing mechanism is the highlight. A black 12-tooth gear under the rear diffuser turns a worm gear and an actuator, so when you turn it the whole wing rises in one smooth motion. It works every time. The butterfly doors are fiddly on the hinges but once they are on properly a spring in each one holds it open or shut.
This is a build that rewards going slowly through the drivetrain section rather than rushing to get the body panels on. Once the chassis is sorted, the rest goes on quickly and the finished car looks the part from every angle.
More from the same build
The member sent us 17 photos in all. These five show the finished car and the chassis from other angles, before and after the bodywork went on.
The adjustable rear wing on the 42172 is one of the better-executed mechanisms in a set of this size. A 12-tooth gear under the rear diffuser turns a worm gear, and the actuator on the end lifts the wing with a clean, consistent action. It is the kind of detail that makes you want to keep turning that gear after the build is done.
Big thanks to this member for taking the time to photograph every stage and send them over. If you have built one of the kits from the library and want your photos on the blog, send them to hello@brickclub.uk. It does not matter how many you took or whether the lighting is perfect. Seventeen photos, a kitchen table, and a yellow McLaren. That is all it takes.
A build diary is more useful than a single finished photo because it shows where the time goes. You can see when the frame starts making sense, where the mechanisms sit, and which stage turns a pile of beams into an actual machine.
If you are building McLaren P1 and you remember to take photos as you go, send them over. The half-built stages are often the bit other members want to see before choosing their next kit.
Ready to build something?
Subscribe to Brick Club and get LEGO Technic kits like this one sent to your door. Build it, enjoy it, send it back. No clutter, no commitment beyond your subscription tier.