Project Nissan Silvia: Part VII

Mounting the adaptor is incredibly difficult. The oil filter mount on the block is stuffed below the intake manifold, behind the alternator, and above the engine mount. Just changing the filter is difficult, but mounting this adaptor, with its giant oil lines and bulky fittings, is nearly impossible. The fittings can't be installed with the adaptor in place, so the oil lines have to be pre-routed and pulled up to the top of the engine compartment so they can be threaded into the adaptor. The one 45-degree fitting also has to be clocked very precisely through tedious trial-and-error.

Mounting the adaptor is incredibly difficult. The oil filter mount on the block is stuffed

We expected to see frighteningly high oil temperatures. The SR20DET has a tiny, four-quart oil capacity, and the heat and high stress loads from 300 hp should really cook that tiny reservoir of oil. It takes sustained high-speed driving to really get oil hot, though, and all our previous track excursions were before we had an oil temp gauge. We were probably running dangerously high oil temps, but luckily, what you don't know can't hurt you.

In normal street driving, oil temps usually hover around 50-60 C (122-140 F). Chasing a Ford GT down Ortega Highway, we managed to get the oil temp up to 75 C (167 F), but that was still only a few short bursts between traffic jams. It's important to remember that while more power makes more heat, it also gets you up to speed sooner, so the engine spends less time working hard. In street driving, our Silvia doesn't seem to need an oil cooler.

Normal driving isn't what this car is about, though. Project Silvia sees regular track duty, and on the rare occasions when we can go 20 minutes without setting something on fire, we'd like to keep the oil supply steady and cool. It may not be sexy or chrome, but happy oil is absolutely critical for keeping the insides of a ridiculously high-output engine where they belong.

We tackled this in two ways. First, a bigger oil pan will allow that heat load to be spread out through more oil so it won't get as hot. There are two commonly available high-capacity pans for the rear-drive SR20. GReddy's finned, cast-aluminum pan is the most common, but we chose the slightly smaller steel Tomei pan, imported by Group5 Motorsports in San Diego, for a simple reason.

We were already whining about the difficulty when we fired up the car and all the fittings leaked. Turns out it's difficult to tighten them enough when the adaptor isn't bolted down. Our solution was to carefully mark the orientation of the angled fitting, then stuff a NAPA 17mm socket and 1/2-inch extension into the center bore of the adaptor to hold it while we tightened the fittings like we meant it.

We were already whining about the difficulty when we fired up the car and all the fittings

The day before we removed the stock pan to weld in the temp sensor bung, we hit one of those asphalt waves that get slowly kicked up when thousands of overweight trucks stop in the same place. The ridge of asphalt was high enough to hit the front anti-roll bar, lifting the car off the ground, bending the bar's pivot bushings and slamming the bar into the oil pan. The stock steel pan escaped only slightly dented, but we fear an aluminum pan would crack under a similar impact. If you're going to be sloppy, haphazard drivers like us, steel may be the way to go.

The Tomei pan has a thick flange, which requires longer bolts. These are included, as are studs and nuts for the mounting holes that sit above the extensions on the sides of the pan. The space between the flange and the pan's side extensions is too narrow to insert a bolt, and even a bit tight for handling the tiny 6mm nuts Tomei supplies, but the pan goes on with only minor finger yoga. The Tomei pan also comes with an extra fitting that seems perfect for an oil temperature sensor. Naturally, it was the wrong size for ours. We welded on another 10mmx1.0mm nut.

The second, more obvious side of our cooling plan is an oil cooler. Since the oil runs perfectly cool in normal city driving, we didn't want the cooler over-chilling the oil. The thermostatically controlled sandwich block we used fits between the engine and the oil filter and routes most of the oil through the filter and directly back to the main oil galley, like normal. A small portion is bled off through the oil cooler before going to the engine, though. As the oil gets hotter, a thermostat in the adaptor opens up, sending more and more of the oil through the cooler.

We got a Mocal thermostatic sandwich adaptor, a 146x235mm Setrab oil cooler, six feet of Goodridge -10 lines and a fistful of fittings from Brits in Sonoma, Calif. Brits also sent along some Goodridge fire sleeve to put around any parts of the oil lines that might contact the car or engine. While the sleeve is intended to protect lines from heat, it can also serve to keep the hard, abrasive braided steel lines from sawing through whatever they rub against.

We mounted the cooler in front of the left front tire where the stock Silvia intercooler went. The Silvia bumper is already designed to direct air here, and the fender liner is louvered to let air out from behind the cooler. If you don't have a louvered fender liner, you should cut a hole for exit air and rivet in some mesh to protect the cooler from the rocks the front tire will fling at it.

It would be temptingly simple to just hang the cooler by its upper mounting flanges, but the constant tension and vibration could easily pull the cooler apart over time. An oil leak in front of your front tire is a bad idea, so we made a flange out of some hardware store junk to support the bottom of the cooler.

With the extra oil capacity and the cooler, oil temperatures are surprisingly low, even during relentless pounding in 100-degree weather. In 20 minutes of shameless flogging, the oil temperature never went above 80 C (176 F), and the coolant temp never went over 87 C (190 F). We have achieved robustness.

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