If there’s one thing we’ve discovered over years of covering the automotive enthusiast hobby, it’s that the folks in the Land Down Under often build non-traditional engines to power their hotrods, and aren’t afraid to choose motivation that isn’t a traditional V8 as most enthusiasts here in the States do.

The engine in this article (the first of two detailing the build) was put together by John Pilla and the guys at Powerhouse Engines in collaboration with Scott Taylor and Nathan Jacobs at Street Machine Magazine. The engine is a 265 cubic inch six-cylinder Hemi that began life between the framerails of Taylor’s Chrysler Centura – a car produced by Chrysler Australia between 1975 and 1978 – that had been removed from the car, taken through a number of moves from house to house, and eventually cast aside.

“I was digging around for a decent 265 Hemi Six to slot into my VG Valiant wagon, and under the parts shelf there was a motor that used to make around 200 horses at the back wheels in my Centura many moons ago,” Taylor says.

Upon initial inspection, the water pump wouldn’t turn, and further digging by Taylor found that the water pump had been smashed hard enough to drive the pump shaft right back into the core of the number one cylinder.

Can It Be Fixed?

This is where Pilla and Powerhouse Engines come into the equation. He suggested tossing the block into the hot tank, and putting a sleeve in to fix it right up for use.

After the block was cleaned up, they sprayed fluorescent magnetic fluid onto the area where the crack existed and used an electromagnet to excite the fluid in the process called magnafluxing. An ultraviolet light was used to help the crack show up, and subsequently a hole was drilled at both ends of the crack to stop it from propagating further into the casting.

Subsequently, the block was placed into the boring machine to clean up the damage from the water pump shaft. As the cylinder was deformed inwards, the boring machine removed the material where it extended into the bore, and a new cast iron sleeve was installed to fix the cylinder.

“The cast iron sleeve was 4.098-inch externally, so Johnny bored the block 4.095-inch to provide a 3-thou interference fit. The step at the bottom of the bore stops the sleeve from slipping out the bottom,” says Taylor.

Next, a 60-ton hydraulic press was used to insert the sleeve into the block, and the sleeve was machined to use a 3.946-inch bore dimension, with .004 meat left to finish the hone in this particular instance.

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Left - The cylinder after the initial boring process to remove the damaged material. Left Middle - Pressing the new sleeve into place. Right Middle - After the sleeve installation, the sleeve extends above the block. Right - Boring the block to near-final dimensions. Following this, a hone is used in three steps to achieve the final bore dimensions and optimal crosshatch pattern in the cylinder walls.

Various Machining Steps

Powerhouse uses a Sunnen SV10, which is programmable to provide exactly the cross-hatch design the builder wants. The hone process is critical, especially in the area of cross-hatch on the cylinder walls.

A Mitutoyo SJ-210 surface tester is used to measure the final dimensions – RPk (Reduced Peak Height) and RVk (Reduced Valley Depth) to ensure the machine’s effectiveness.

“We are also keen on the RK (Peak to Valley) number which is the centre of the cross hatch where the ring spends 90 percent of its life,” Pilla explains. “We test every block, as different materials require different honing techniques.”

The honing process is a coarse diamond hone, followed by a fine diamond hone, then the bore is finalized with plateau brushes.

“If the valleys in the material are too deep they’ll hold too much oil which leads to high consumption, but if they’re too shallow it leads to accelerated ring wear,” says Pilla.

Final machine steps during this portion of the build had the sleeve installed and the block bored, decked and honed to its final dimension to await the rest of the machining processes to get the engine ready for service.

In the second step of the build (seen in the above video), the gang revisited the block to finish off the machining steps and prepare the block for assembly, which we’ll cover in an upcoming article with more videos.

The block was set up to be line honed, which required the main caps to be ground flat and true. For this particular engine, four thousandths of an inch cleaned up the caps. Powerhouse also performs a unique machining process to the main caps, where they knurl the sides of the main caps to prevent cap walk.

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Left - Powerhouse knurls the edge of the main caps to prevent movement under power. It's an added step of insurance. Middle - Measuring the line bore with a dial bore gauge. Right - Powerhouse using the Sunnen CH-100 line hone to true the mains. This ensures that the crankshaft will spin effortlessly.

Budget-Minded Build

In the interest of controlling costs, the factory connecting rods were re-used in this build. The old connecting rod bolts were pressed out to set the rods up for the installation of a new set of ARP‘s Wave-Loc rod bolts.

The mating faces of the connecting rods were cleaned up on the rod grinder to allow Powerhouse to resize the connecting rods and provide fresh bearing surfaces, and the rod bolts were pressed in with a 40-ton press prior to the resize process. The bolts are also torqued to the correct specification before the big ends are resized.

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Various steps of the balancing process; measuring the big end of the connecting rids, spinning the crankshaft to find its balance point, and the final reading - everything in spec!

Each of the rods were weighed to find the lightest one, and each of the other rods were subsequently matched to that unit by removing weight from the big end of each rod.

The long straight-six crankshaft was installed onto the CWT Industries balancer where the process of balancing took place. The block was then align-honed to ensure that the crankshaft rides straight and true in the main bores.

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Left - Installing the new rod bolts. Right - Resizing the big ends of the connecting rods.

Check out the photos for more information on these steps of the buildup, and stay tuned next week as we bring you the followup article on the engine’s completion and dyno session!

Thanks very much to the guys at Street Machine Magazine and Powerhouse Engines for sharing the photos and details of this build with us!