Working smart

How a New Zealand-based engine builder is combining technologies to make small batch motorsport parts more accessible

-  CHARLES CLARKE

Readers might remember that in Racecar Engineering V28N5 we featured the Hartley V12, a naturally aspirated V12 engine, based on 5.0-litre Toyota castings, which produces about 750bhp at 9500rpm.

Since then, the Palmerston North, New Zealand-based company behind it has produced a second version of this potent powerplant, designated Prototype Number 2, which has twin turbochargers and is estimated to produce upwards of 1500bhp on full boost, and a more modest 1050bhp at 12psi of boost pressure.

While the figures for both units are impressive, equally noteworthy is the way they are produced. This is because, in order to speed up manufacture and reduce cost, Nelson Hartley, co-owner and engine designer (and, incidentally, brother of former F1 and LMP1 driver Brendon) at Hartley Engines and Motorsport, has taken to making some of its parts using 3D printing, instead of traditional machining.

For example, instead of machining the entire intake manifold from a solid billet, the flanges have been water cut from 8mm aluminium sheet stock, the throats 3D printed and the throttle bodies sourced from the standard Hartley Engines parts bin.

Zero leakage

Assembled, it is lighter, less expensive and less machine intensive than the previous billet part the company used on Prototype Number 1. And because of the quality of the 3D printed surface, internal flow characteristics are as good, if not better.

‘Because you can get some leakage between 3D printed layers, I coated the internal surface of the throats with one layer of epoxy,’ explains Nelson. ‘Then to test the strength of the 3D printed plastic, I put 100psi into the throat of the 3D printed fabrication and got zero leakage.