This is the new Moroso Super...
This is the new Moroso Super Accumulator PN23902 that holds 3 quarts.
Jeremiah Ipatis, Frackville, PA: I recently bought a '72 Vega with a very stout 350ci small-block Chevy. I want to install an oil accumulator and oil cooler for preventive maintenance, as the car will be a strip-only and the motor routinely spins above 8,000 rpm. I'm going to run an oil filter relocation kit and am leaning toward a dual filter kit. There's no way around this because of tight oil filter-to-header clearance. My motor is running a high-volume oil pump. If I decide to run a single filter, which adapter plate should I stack first-the accumulator or the cooler? If I run a dual-filter setup, should I install the accumulator or cooler on the filter closest to the block, or does it not matter? Also, would it be more prudent to run the dual filter as opposed to a single-filter system?
Jeff Smith: Sounds like a pretty radical engine if you're spinning it to 8,000 rpm, Jeremiah. Frankly, with that kind of rpm I'd be much more concerned with my valvetrain stability and the weight of all the valves, springs, retainers, keepers, rockers, pushrods, and mechanical roller lifters than I would be about oil temperature and an accumulator. This assumes, of course, that you're using a high-quality forged-steel crank, the best connecting rods you can buy, and lightweight forged 2618 alloy pistons. But since that's not what you asked about, we'll address your actual question.
For a drag-racing application, an oil cooler will be merely added ballast. Drag-racing engines run for such a short period of time that oil temperature rarely exceeds 180 degrees F, regardless of your water temperature. Oil coolers are much more important on a road-racing engine where continuous operation can spike oil-sump temperatures well beyond 300 degrees F. Excessive temperatures like this contribute to additive package breakdown, which can quickly cause excessive wear and bearing failure among other catastrophes. In dyno testing, it's common to see a significant power increase with hot, 220-degree oil temperature over cold oil at, say, 150 degrees. This is one reason drag racers can get away with extremely low oil viscosities like 0W-5 oils, since the oil temperatures rarely get hot enough to have a negative effect on engine durability. All this means is an oil cooler is not necessary on your drag-race engine.
You also mentioned a high-volume oil pump, which gives us a great opportunity to dispel a common belief that the small-block Chevy prefers high oil pressure and volume. All pumps require power to create pressure and volume. Oil pressure is the measure of resistance to flow, which means the more pressure, the more power it takes to spin the oil pump. If the engine has been assembled properly with relatively tight clearances, this means the mains and rods will be shedding a given amount of oil based on those clearances. The more oil released, the more oil windage that must be treated to prevent high-rpm power loss. Most small-block Chevys don't need a high-volume oil pump and probably not more than 50 to 55 psi of oil pressure even for an 8,000-rpm engine. The old standard of 10 psi per 1,000 rpm is antiquated now, with higher-quality components and better lubricants. In addition, that high-volume/high-pressure oil pump puts a greater load on the distributor gear, creating more heat and contributing to increased gear wear. This causes increased backlash between the cam and distributor gear that will cause ignition-timing variation, called spark scatter, at high engine speeds. Did you know that distributor-gear backlash is something you should check on an 8,000-rpm engine? Until recently, neither did we.
For the benefit of those readers who may not know, an accumulator is a separate pressurized canister that stores 2-3 quarts of oil connected with a high-pressure line directly to the engine. In the event of a wheelstand or a hard launch, g-forces may push oil away from the oil-pump pickup. This causes the oil pressure to quickly drop to zero. As the oil pressure in the engine begins to fall, the pressurized oil in the accumulator is pushed into the engine to supply the engine with oil until it can be restored by the pump. Both Canton and Moroso offer these accumulators, which Canton calls an Accusump. There are different sizes depending on the amount of oil you wish to carry, from 1 to 3 quarts. These accumulators can also be used to prelube a cold engine before startup, which will reduce bearing wear, which is a great feature for race engines. These accumulators can be plumbed into the engine at any point but should not be plumbed to run through the oil filter first.
As for an external filter, there are several companies offering kits. A single large-diameter filter is fine for what you're doing. These should be plumbed with -10 or -12 hoses to minimize pressure drops between the filter and the engine. The less expensive filter adapters that bolt to the engine are cast aluminum, but we prefer the more durable billet bypass plates. The Moroso billet bypass plate (PN 23782) is available for $54.95 from Summit Racing. Canton makes a similar piece. For example, on our CC Mustang getting the small-block Ford engine this month, we will be installing a bypass to mount an external filter and oil cooler on the car. The filter will be plumbed upstream of the cooler to keep the junk out. We're doing this because eventually this car will see serious track duty on a road course, and we don't want to cook the motor.
Canton Racing Products; North Branford, CT; 203/481-9460; cantonracingproducts.com
Moroso Performance Products; Guilford, CT; 800/544-8894; moroso.com