When BRE tried the Z again at Willow, they first began to experience the deadly vibration that would delay the 240Z’s debut until well into the season. Above 7000 rpm for the first extended run, the vibration came on so suddenly and was so severe that every bolt holding the crank to the flywheel sheared as if it had been cut with a laser. It was like an explosion occurred in the bell housing. Fortunately, a scatter shield protected Morton’s feet from serious injury.

Upon inspecting the damage, Oehrli explained that all inline sixes suffered from this phenomenon, but since most production engines never experienced high rpm, the problem was almost unknown. To keep the lightened flywheel attached to the crankshaft, six dowel pins were machined and press-fitted into the crank’s mounting flange to resist the shearing forces. A report was sent to the factory describing the third harmonic problem, along with possible solutions. There was no response.

On the next test, the flywheel stayed on the crank, but now the vibration sheared the bolts that held the clutch housing to the flywheel. When that was solved with stronger bolts, the blades holding the pressure plate inside the clutch housing sheared. Special locating pads were designed and installed to keep the pressure plate in line.

Oehrli also tried adapting a Chevrolet harmonic balancer to the front of the crank, but the vibration was still so intense that friction melted the damper’s rubber bond, pitching the balancer’s outer ring.

There was no way they could race the 240Z and hope to last even a few laps. The now-obvious problem had a solution, but it would mean a completely new design for the crankshaft, including proper counterweights to offset the crank’s internal wind-up at high rpm.

The team needed some 8000 rpm to extract the engine’s full potential, but without the proper internal components there was no way to sustain the engine’s required speed. The BRE crew sent more reports to Japan, but again there was complete silence. They had no way of knowing if some solution was being devised or if anyone at Nissan even cared. Mr. K was patient and understanding, but they felt frustrated and unproductive.

Later they began to grasp the reason behind the manufacturer’s silence: It was simply a Japanese custom to not recognize direct criticism, which is how they perceived BRE’s reports. Unbeknownst to them, the problems were being worked on, but Nissan could not admit it as that would have indicated someone had made a mistake–an unacceptable cultural error. The team was learning.

Morton Saves the Day

Incredibly, Morton was holding his own in the roadster against the faster Triumphs and Porsches, but there were four of those and only one Datsun. To make the podium and secure vital points, he had to beat at least two at each race–no easy deal.

The story about the last-minute arrival of new cranks from Japan is so bizarre that it can’t be related here, but suffice it to say that when they finally did arrive and were installed, the engines ran smoothly on the dyno to 8000 rpm.

BRE was ready, at last, to go racing–well, almost. They did a few more track tests in private to make sure.



The new division cranks did what they were supposed to, but on track we found a new issue: Thanks to the higher engine speeds, oil was somehow not getting to the oil pump’s pickup. Morton was noting a serious drop in pressure at speed.

Since he was also one of the team’s best fabricators and was responsible for building our high-capacity oil pans, Morton took a closer look at the situation. Based on how he envisioned the oil flow before and after the crankshaft upgrade, he redesigned the pan’s internals, its windage tray and the pickup. Everything finally worked: no high-rpm smoke, and the engine’s sound was so sweet we could hear his every shift point around Riverside.

From that point forward, Morton was on top for almost every race. The 240Z had suddenly gone from non-starter to the fastest C Production car on the grid. First-place points for the final few races came rolling in like dollar signs on a Vegas slot machine, guaranteeing a starting position at Road Atlanta for the Runoffs.