The Nissan LZ18 engine used a custom built dual overhead cam arrangement with four valves per cylinder, and was first seen in 1975 in the Southern Cross International Rally in Australia under the hod of a pair of factory “Works” Datsun Violet 710s. With a limited number of cylinder heads created to conform to the FIA’s homologation rules, the engines are few and far between today.
Recently, Neil Taylor got his hands on a two-door Datsun 710 with plans to build it into a replica rally car–but was stuck on where to locate an engine.
The object of his search, believe it or not, was sitting on someone’s living room floor underneath a circular glass top acting as a coffee table. This particular LZ20B was assembled from parts that were discarded and considered worn-out, then put into service ‘under the glass’, with the task of holding up the glass and a few magazines considered its future.
Until Taylor’s efforts 25 years later to procure the engine were successful, and it was subsequently dropped at the front door of Les Collins Racing, where its reconstruction into a high-winding beast began.
The steel crankshaft and connecting rods that were in the “Coffee Table” engine were far from ideal, as they had been part of a catastrophic engine failure and removed from service for that reason.
“Rods were found in sports sedan racer Barry Bray’s collection and very luckily, another mockup engine was discovered in Japan that had a good crank and also an excellent bare cylinder head and we were able to part them from its owner,” says Collins.
Back in its heyday, the LZ20B was capable of 240 hp–which is where Collins set the bar for the restored engine. The 89mm bore was worn out, so LCR performed a sonic check to determine the block’s worthiness for overbore, and made the decision to poke it out another .5mm to clean it up. Pistons were selected to set the compression ratio at 10.5:1.
One of the unique things about the LZ20 was the camshaft drive–seven gears and three sprockets combined with a double row chain drive to run the camshafts.
“We had about 5 sets of gears and housings available – all in rather poor condition, and ended feeling rather lucky again that we managed to make a good set after lots of crack testing, welding, machining and fitting new gear shafts, etc.,” says Collins.
The end result of the restoration process? 241 hp at 7,500 rpm, and a big smile on the owner’s face.