LAST time you saw my VL Commodore Street Machine Drag Challenge build, we were down at Geelong Differential Services sprucing up the carís BorgWarner rear end. Now itís time to get stuck into the engine build.
Yes, originally I wanted to do a budget stockbottom- end turbo build, but I also wanted to run 10s, and I just wasnít going to achieve that goal without boosting the standard RB30 to within an inch of its life and essentially creating a ticking timebomb.
So I put in a call to John Pilla at Powerhouse Engines, builder of some of the most bad-arse motors in the scene. Most people will know John for his crazy blown and injected burnout engines from cars like Steven Loaderís UCSMOKE and Paul Cookís BLWNVC, but he does everything from humble Holden six-pots right up to the crazy stuff.
Heís also been looking after the 1600hp twin-turbo LS in Adam Rogashís seven-second NOSHOW ClubSport, which won the Haltech Radial Blown class at Drag Challenge last year and Turbosmart Outlaw Blown the year before.
So John understands how to make these highhorsepower street motors last. Weíll be checking in with Adam in future issues, as heís handling the fabrication and tuning side of the build.
I already had my Crow Cams Street Race Turbo camshaft and valve springs from when this was going to be a stock-bottom-end build, so I just needed a set of rods and pistons. It turns out there arenít a whole lot of options when it comes to aftermarket rotating assemblies for single-cam RB30 engines, so I went with a set of Spool Imports CP Carrillo forged pistons and Spool Drag Pro I-beam rods.
The standard RB30 crankshafts are virtually bulletproof until you start making around 1000hp, so weíre sticking with the factory item and just giving it once-over. My power goal for this thing is around the 600-650hp mark, and we should be able to hit that with relatively low boost. Itíll be enough to get us low 10s, and if we turn up the wick I reckon weíll see nines Ė this combo will safely handle around 30psi of boost.
The rest of the set-up will include a Turbonetics 64/65 billet-wheel turbo; Plazmaman intercooler; Turbosmart wastegate, blow-off valve and fuel pressure regulator; custom intake
and exhaust manifolds; and a flex-fuel system.
Itíll all be controlled via a Haltech Elite 2000 computer. Youíll read all about that stuff in future tech stories, but for now letís get stuck into this engine build at Powerhouse Engines!
A MASSIVE thank you must go to John Pilla and all the guys at Powerhouse Engines for their work on my fully hectic RB30 VL Turbo build! If you need an engine built or a machine job done, give them a call on (03) 5623 3447.
My stock-standard, naturally aspirated-spec Nissan RB30 straight six is stripped down completely. The original rods and pistons are turfed; the only bits weíre keeping are the block, crankshaft and crank girdle and the cylinder head. Once disassembled, it all goes into the acid bath for a few days to wash away the grot that has built up after a hard life on the road with infrequent servicing
Once the block is clean we check it over for imperfections and give all of the bottom end faces a sand. Then we can test-fit the crank girdle using my new ARP main studs and get ready to give the block a line-hone
With the crank girdle in place and our main studs torqued up to their required settings, we measure up the main tunnel for bearing sizes
With about one thousandth of an inch to come out of the tunnel to get us spot-on for factory bearing clearances, Trevor gives the block a line-hone. This takes a tiny amount of material off each edge of the main tunnel, and our aim is to get them all exactly the same. While it would be fine for an ordinary engine to have small imperfections be fine for an ordinary engine to have small imperfections with slightly varied bearing clearances, we want to get this thing as perfect as we can. Factory-spec bearings also have a bottom and a top tolerance, which weíre right in the middle of Ė perfect!
Before we bore out the cylinders we deck the block to ensure that itís dead flat and square. After that Trevor will be boring out the block to suit my new 86.5mm forged pistons; the factory bores of an RB30 block are only 86mm
Trevor takes about 13thou out of each cylinder bore.
The hard part here is making sure you remove the same amount of material from the top through to the bottom, as the bores are never quite straight from the factory
With the bores all straight itís time to torque-plate-hone the block.
This simulates having the cylinder head bolted to the block, so that itís under tension. This time weíre using a special diamond stone that places crosshatches in the cylinder walls, so that they hold and retain oil
We give the RB30 crankshaft a crack test to make sure itís all good to use. Trevor shines an ultraviolet light onto it, which, when combined with the fluid applied to the crank, shows any cracks as a fluorescent light.
Fortunately, the stock crank is crack-free
Now that we know there arenít any cracks in the crank, we need to make sure itís straight. Trevor uses a dial indicator that shows how straight or bent the crank is as it turns. Mine passes all of the tests
Because the oil gallery plugs in these RB30 motors are aluminium, they can corrode and shrink while theyíre in the acid wash. If we donít replace them they could potentially fall out and weíd lose oil pressure
Most of the time there are small differences between parts that would on the surface appear identical. So Trevor measures the diameter of the big end (the bit with the big hole) of each Spool conrod and then uses the rodhone machine to take a small amount of material out of five of the six rods so that they all have the same sizing
Next, the rods are tested to ensure theyíre all perfectly straight and the same length
The rods arenít all necessarily the same weight either, so Trevor finds the lightest one and then takes a small amount of material off each other rod to even them up. This is first done with just the big-end weights and then the overall weight of each rod
The same process is carried out with the pistons.
Each one is weighed and then small amounts of material are removed to make them all weigh the same. To minimise the amount taken off each piston, the heaviest pistons are matched with the lightest gudgeon pins, and vice versa
Trevor goes over the crankshaft to give it a nice smooth finish ready to mount the rods to during final assembly
Before we start any machine work on the cylinder head, we need to clean it up with a sandblast k
With the cylinder head given a thorough clean-up, itís ready to have its face machined. As when we decked the block, this gives the face a smooth, perfectly flat finish so that it mates up with the block nicely
Next we give the intake ports a clean-up and smooth some of the rough edges to improve airflow. This isnít as important with a turbo engine as it is with an aspirated one, but it will help
All of the new Manley stainless-steel valves are checked for size against the cylinder head, and Trevor gives them a grind to ensure all of the angles are identical and they sit nicely in the valve seats
Now Trevor cuts the valve seats to match the angle that he put on the valves in the previous step. This ensures the valves sit close to flush and evenly in the seats
Finally, the Crow camshaft is test-fitted in the tunnel.
The Street Race cam is designed to fit without any modification to the tunnel so we donít need to machine it; Trevor just gives it a polish. With the cam in, we test-fit the rockers with the valves, and everything is then ready for final assembly.
Next time weíll be back at Powerhouse Engines for final assembly, before we get ready to put some boost into it on the engine dyno and see what she makes! s