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We Add Spark to Our Old Land Cruiser

Posted in How To: Electrical on March 6, 2018
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It’s not uncommon to find a small-block Chevy engine under the hood of an FJ40 Land Cruiser. They make more power than the factory six-cylinder and are lighter to boot. We had several compelling reasons for keeping the factory F engine in our FJ40 though. After performing several engines swaps we learned that they are never cheap, even if you already have the engine. Bellhousings, exhaust, wiring, radiators, motor mounts, new drivelines . . . the costs add up in a hurry. And this creampuff is too original for a V-8 swap or 1-ton axles. While it would be more capable on the trail with these modifications, the vehicle would likely go down in value!

In contrast, better performance from the stock F engine would be beneficial for a number of reasons. Just because we are keeping the factory engine doesn’t mean that we aren’t looking for more power, mileage, and reliability. To accomplish all of those goals in under an hour, we recently added a Performance Distributors Davis Unified Ignition (DUI) distributor and Livewires plug wires to our Land Cruiser. Unified mean that the high-voltage coil is located inside the distributor cap, and only one wire is needed to complete the installation. The coil produces 50,000 volts with a low enough amperage draw that we don’t need to be concerned about taxing our antiquated wiring system.

Our old distributor and coil were adequate, but there was definitely room for improvement. The good news is that it’s stabbed in an engine that was rebuilt shortly before we purchased the Land Cruiser (we got receipts). Another reason to keep the six-cylinder.

While it is similar to a GM HEI distributor, we experienced several benefits that are unique to Performance Distributors. The company tunes the advance curve for each application using a Sun distributor machine to ensure a precise timing curve tailored for your vehicle. The distributor is also virtually waterproof, making it perfect for off-road conditions from water crossings to mud bogs.

We complemented the distributor with a fresh set of NGK V-power spark plugs and Performance Distributors’ Livewires. The Livewires use 8mm wire covered by a heat-treated fiberglass sleeve that is rated up to 1,400 degrees F, which is a temperature we hope our old Cruiser never meets. Adding Performance Distributors’ DUI distributor and Livewires resulted in quicker starting, a smoother idle, improved throttle response, and even a bump in mileage. All in less time than it would take you to find headers that fit your engine swap.

We started by noting the firing order and setting the timing to top dead center before removing the old distributor. This was confirmed by the rotor position and the timing mark on the flywheel.
This is an instance where size does indeed matter. Engine bays with dual batteries or air compressors might have space issues; however, we had no issues fitting the Performance Distributors DUI distributor under the hood of our Land Cruiser.
The DUI distributor is similar to the HEI General Motors distributor with a 50,000-volt integrated coil and low-amperage draw built right into the distributor so minimal wiring is required. We retained the wire from the original coil and added the included spade connector from Performance Distributors to power the distributor. A tach pickup is also included for those running tachometers.
Both the original distributor and the new DUI distributor use vacuum advance, which comes from the intake manifold. Performance Distributors provides a custom advance curve that dramatically increased drivability, and the DUI distributor is covered by a one-year warranty from date of purchase.
We added fresh NGK spark plugs at the same time as the distributor and Livewires. Performance Distributors states that the ignition is powerful enough to open the gap up to 0.055 inch, so we did exactly that.
It’s clear that our old distributor was not providing the cylinders enough spark to completely combust the fuel. Increased voltage and more precise spark delivery from Performance Distributors should resolve that issue.
Livewires were added to deliver the increased voltage to the spark plugs. The spiral-wound core features radio suppression so there’s no concern of computer interference or radio noise on modern vehicles.
The 8mm wires come in the proper length for our engine and are even numbered for foolproof installation. They are available in black, blue, purple, red, silver, or yellow.
The complete installation took us under an hour, although we did spend extra time cleaning up the Livewires routing after this photo was taken. We added Performance Distributors wire looms to accomplish this task.
The final step was to time our F engine after installing the new distributor. The timing mark on this engine is not on the crank pulley but rather the flywheel. We dialed in 7 degrees of initial timing, and the engine purred and ran smoother than it ever has in the past.


Performance Distributors
Memphis, TN 38132

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