Outside the Box: Nissan V6 Race Engine


If there is a consistent complaint we hear time and again about racing, it’s almost always about the cost of racing and how nothing ever changes. OK, maybe that’s two complaints, but you’ve probably heard them both too.

Part of the problem comes from the fact that tracks and sanctioning bodies rarely stray from the status quo. We are, after all, still largely racing carbureted first generation Chevy small blocks and Ford Windsors. It has been years since you could reliably find race-quality parts in the junkyard, and as the aftermarket as further refined the quality of their products, the costs only go up.

That’s no fault of the manufacturers; they are just what we as racers demand. We’re always asking for higher quality, lower weight parts for our race cars. And if we’re willing to pay for it, who can blame them?

There will always be a place for big V8’s and the top-grade racing components in the higher levels of racing. But entry level classes–at least a select few–need to return to mostly stock engines that can still be scrounged up from junkyards for a fair price.

One option we found recently is the Pro Six class that has been racing at Langley Speedway in eastern Virginia and some other tracks. And you’d better believe the Pro Six class is thinking outside the box with their engine rules. Instead of the usual cam-in-block engine, the rules specify one of Nissan’s overhead cam V6 engines–a VG30E to be precise.

The VG30e series of engines showed up in everything from Nissan Pathfinders and Quest minivans, to Maximas and 300ZXs. In stock form it produced 153 horsepower and 182 lb/ft of torque. It has a single overhead cam and two valves a cylinder matched with fuel injection.

It certainly doesn’t sound like a race engine, but surprisingly, it does work quite well as an affordable entry-level race engine. When our friends at KT Engine Development set about rebuilding one for a racer running the Pro Six class at Langley, we wanted to see for ourselves.

The car owner, Chris Florian, says he enjoys racing in a class powered by the unusual engine. The limited power makes the cars more controllable for young drivers as they gain experience, and it also helps keep costs down because there isn’t a dedicated stock car racing aftermarket developed for the VG30. “The bottom end of the engine is basically the same as Nissan used for the twin cam turbo engine,” Florian explains, “so they are pretty much bulletproof. Before we sent the engine in to KT’s for a rebuild, we went for years racing the engine. And they make for great racing–we won, I think, five races, but we also had four different winners. So far it has been great.”

We’re not saying that every track needs photocopy the rule book and start up its own Pro Six class–just that this is a very interesting solution to help entry-level racers go racing without spending a fortune. When you get down to it, there are a ton of good options like this, it just requires a little thinking outside the box.



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It certainly doesn’t look like your typical race engine, but this V6 Nissan–yes, we said “Nissan”–engine is just the type of outside-the-box thinking we need for low-cost, entry-level racing.



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The basis of the engines used in the Pro Six class Nissan’s VG30E block, which appeared in everything from pickup trucks, to minivans and even the 300ZX throughout most of the 1990’s. As you can see, the design features an iron block with one-piece main cap assembly, and racers we’ve talked to say the bottom end is virtually bulletproof.



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The stock cylinder bore is pretty small at just 3.43 inches. Rules typically allow a maximum overbore of 0.020 or 0.030 inches. For this rebuild, KT Engines honed the cylinders a minimal amount so that the racer should still be able to use this block for future rebuilds.



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A effective cost-saving measure is requiring that only the stock crank be used. The V6 crank with its individual rod journals may look a bit odd compared to a traditional V8 crankshaft, but it is more than strong enough to handle the limited power these engines produce.



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Thankfully, KT Engines’ engine assembler Mike Blackwell says the stock crank checked out to spec, so it can be used for another go-round of racing. The rod journals spec in at 1.967 inches while the mains measure up at 2.479 inches.



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Just like the crank, the rods have to remain stock. But the good news is it’s a pretty good unit, and they seem to hold up well. An upgraded through-bolt in the cap is about all you can do, but it’s also all you need.



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Here, the number-one rod and piston have been installed on the crank. As you can see, there’s only one rod per throw.



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Flat-top replacement style pistons keep the compression up and costs down.



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The oil pan is the original unit that has been modified with a kickout to hold more oil and improve windage.



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The VG30 series of engines use aluminum overhead cam cylinder heads. An upgraded three-angle valve job is allowed, and definitely recommended to help improve flow into and out of the combustion chambers. But you’ve got to stick with stock-size valves and any port work is strictly verboten.



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In Langley’s case, the rulebook requires stock camshafts. But because the VG30E appeared in several different cars there are a few different options available. Cams are limited to a maximum lift of 0.393 inches and an intake/exhaust duration of 264/262 degrees.



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The VG30E uses a unique oiling arrangement where galleries feed oil into the cams through the journals. Then oil then exits through ports on the heel of each cam lobe to provide a cushion of oil between each cam lobe and its corresponding flat-tappet lifter.



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The lifter guides are machined into aluminum plates that bolt to each head above the camshaft. Here, the flat-tappet lifters are being dropped into place, then the plate is flipped over and bolted down.



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Here’s a look at a complete head with the shaft-mount cast rockers in place.



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KT Engines chose a composite gasket from Fel Pro to seal the heads to the block because you can get the gaskets thinner than a typical Multi-Layer Steel gasket, which helps keep the compression up.



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Despite switching from fuel injection to a carburetor, the OEM electrical system can be retained. KT Engines simply checked over everything to make sure it was working optimally before reinstallation.



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Conversion to the required Holley 500 cfm two barrel is easy. A two-barrel adaptor bolts right up to the intake manifold.



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The distributor is spun off a gear at the front of the right-side camshaft. Timing is set exactly like you would on your old-school V8.



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On the dyno the little V6 performed surprisingly well. Horsepower tops out at just under 200, but it has a broad torque curve and we’re told the results make for a peppy race car on the track.



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