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| Big Honking JWT C9 cams, just what we needed to extend our powerband out to 8000 rpm. These had a serious lope at idle even with the overlap killing variable valve timing of the Rev Up motor. |
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| The cylinder head had to be modified to clear the big lobes of the C9 cams. |
Since we wanted a wider and higher powerband, JWT supplied us with a set of their biggest C9 camshafts and high performance valve springs. The C9 cams have an intake and exhaust duration of 283.5 degrees, 11.5 degrees more than the C8R cams we were running previously. The lift was a whopping 0.516 up from the older cams 0.473. These are big cams that should give us the thousand rpm more we need in our powerband. The cams are so big that the lifter bucket holes and the sides of the head near the cam lobes must be ground to clear the lobs as they turn! So as we rounded up parts, Nick gave the block’s bores a light honing, enlarged the water passages, touched up the valve job, clearanced the head for the cam lobes and cleaned everything.
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| Nick ground the head casting on the sides of the lifter bucket boss and on the side of the casting as well to clear the cam lobe. |
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| You can see how close the lobes are here. The C9’s are the biggest VQ cams on the market. |
On any turbocharged motor, pistons are probably the most important component. Since we didn’t have any time at all, we had to go with a company that had a proven design sitting on a shelf. We would have preferred to spec something trick for one of our builds but there was simply no time. After seeing what was immediately available, we settled on JE pistons. We are very familiar with JE’s engineering prowess. JE is also an ISO 9000 certified company which means they consistently deliver OEM world class levels of engineering and quality. An ISO 9000 certification is exceedingly difficult to earn, especially for a performance parts company and JE is one of a handful of performance companies we know that, like KW suspension, has joined this elite club.
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| The ports, valves, combustion chamber and valve job are completely stock. Making power is not a problem with the VQ and we didn’t need to do expensive head work to get more than enough power for what we wanted to do. |
JE’s standard bore VQ35 turbo piston is designed for a bore of 95.5 with the proper 0.005” piston to wall clearance built in. JE is capable of holding very tight production tolerances so it is fine to install them with just clean up honing for ring seating. The pistons are machined from a forged 2618 low silicon alloy blank. 2618’s low silicon content makes the alloy much tougher and ductile than high silicon forged and cast pistons. This toughness is very desirable for a turbo piston and competition use. The only drawback to 2618 over cast and high silicon forgings is that it expands more with heat and thus must use a wider piston to wall clearance. High silicon forged pistons can run clearances of 0.003” of an inch and stock cast pistons can run as tight as 0.0006”. Really about the only disadvantage running a larger clearance means is that the engine will rattle more when cold, possible use a little more oil and have slightly less ring and bore life. None of this really matters in a really high performance motor where the strength is the most important aspect.
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| We upgraded our cam followers to the HR engine’s DLC coated lightweight forged steel cam followers. The valve clearance is controlled by this little pedestal on the underside of the follower. You can buy different heights of these followers from Nissan to adjust valve clearance. Nick faced off these to set our valve clearance. |
