We didn't get 10 miles down the highway with our new 496-inch big-block before the smile faded and turned to a frown. The rearview mirror told the story: We were trailing a noxious cloud of oil smoke that made Kuwait's burning oilfields look like a Boy Scout camp fire. What the hey? Had we just turned a $7,500 motor into a boxful of industrial art Christmas ornaments? This was more than machine oil burning off a new exhaust; this was a serious Exxon Valdez.
We tried snugging those pleated cotton-gauze breathers. We tightened the valve cover bolts. We tried new valve cover breather grommets. We swapped on different breathers.We even tied old rags around the base of the breathers to stem the engine's flow of blood. But no dice. A small trickle of oil was dripping from both breathers onto the valve covers, and then onto the hot exhaust. And that was after making our best effort at placing the breather holes away from the pushrod oil holes at the top of the rockers. Were it not for the fact that we had seen this same problem in hundreds of other street cars, we would've been stymied. This is an extremely common occurrence on high-powered street machines, so when we went looking for a kit, we were shocked to find there isn't a single engineered system on the market.
Our Chevelle's breather system (clockwise from left) includes a breather tank from Summit, -6AN fitting with a 3/8-inch barb, custom plates for mounting the breather tank, 3/8-inch emission hose, two QFT valve cover breather clamps, two PCV breathers from Spectre Performance, a 3/8-inch OD "Y" barbed union, and tie-wraps.
Yet it's not like designing a breather system is hard, as we soon found out. Turns out, a lot of companies make the different pieces and parts, but you're on your own locating them and putting them together in a cohesive system. To that end, we hope this story will give you a major shortcut to solving your own oil-burning woes. As a side note, passive breather systems like ours are far more common on race cars, but their popularity is being quickly surpassed by more expensive crankcase evacuation systems, which have the additional benefit of a 20 to 40hp boost (typically) at the flywheel. They use a vacuum pump to pull the miasma of oil, air, and exhaust blow-by from the crankcase, then pump it into a breather reservoir like the one in this story. At some point, we may upgrade to an evac system, but for now we'll be happy without the massive smog tail.
When we finished, the sum of $351.28 had vanished, but we're confident you could make some substitutions to lower the price. If an alert vendor out there would like to package such a system under one part number, we'd be all too happy to give that soul some free ink, but until then, you can duplicate our system. And how well does it work? Since we put it on, we haven't had a single drop of oil hit our headers.
WHERE THE MONEY WENT BREATHER SYSTEM COMPONENTS Item: Source: Part No.: Cost: 3/8-inch emission hose (4 ft.) AutoZone n/a $5.00 3/8-inch barbed "Y" fitting AutoZone n/a $3.50 breather tank {{{Summit}}} SUM-G1504 $27.95 custom aluminum mounting plates (2) Advanced Waterjet n/a $30 -6AN to 3/8-inch barb straight fitting Summit/Aeroquip AER-FCE1512 $7.88 Pressure Master valve cover seals (set) Summit/Earl's EAR-29E04BERL ${{{62}}}.99 PCV breathers (2) Jeg's/Spectre 865-4921 $89.98 Valve cover breather clamp (2) Jeg's/QFT 793-{{{100}}}-1 $123.98 Total: $351.28 STREET SWEEPER '68 CHEVELLE THE COST SO FAR Item: PHR issue: Cost: 1968 Chevelle {{{Malibu}}} April 2007 $12,000 {{{V40}}} Wheels & Nitto NT01 tires April 2007 $2,041.98 Vinyl graphics April 2007 $169 CPP front suspension May 2007 $1,229 {{{M}}}/T slicks & skinnies, Summit Star drag wheels May 2007 $927.60 Currie 9-inch rear June 2007 $2,896.20 Misc. parts for rear install June 2007 ${{{57}}}.{{{90}}} CurrecTrac rear control arms June 2007 $524.90 Morris Classic Concepts seatbelts August 2007 $325 Rear springs, air bags, QA1 shocks September 2007 $906.88 Howitzer 496 big-block Chevy October 2007 $7,523.37 Engine install, trans, shifter, exhaust, fuel system, misc. November 2007 $4,861.72 Breather system for engine December 2007 $351.28 Total: $33,814.83