Chevy R07 NASCAR Engine - The Future Is Now

Chevy's NASCAR Teams Begin A New Era Of Racing With The R07 Small-Block

Dan Ryder Dec 27, 2007 0 Comment(s)
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The year was 1955. President Eisenhower resided in the White House, Rosa Parks refused to sit at the rear of the bus, and the Brooklyn Dodgers defeated the New York Yankees in the World Series. The year 1955 also marked the introduction of the Chevrolet small-block engine. It measured 265 cubic inches and soon made the division's passenger cars the ones to beat at the track. Over time the small-block reached 400 ci, and it is still being produced in GM's Toluca, Mexico, plant for over-the-counter replacement purposes.

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Pictured here is the deck surface of the SB2 cylinder head (pictured here), and the R07 cylinder head (below).

As the 1998 NASCAR Winston Cup season began, it was decided that the Gen-1 (SB1) Chevy engine had reached its limits. With parts having a short lifespan, and no significant gains in power, Team Chevy gained approval to begin use of the newly designed SB2 (small-block 2). While the bottom half was very similar to the SB1, the cylinder head design changed drastically. The port layout, valve angle and combustion chamber design were all new. The SB2 would help level the playing field against other manufacturers. The SB1 made decent power, but needed more torque down low to get off the corners faster. The SB2 provided this additional gain in torque, and this engine was used in Nextel Cup Racing until this year.

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Notice the more consistent, uniform design of the plug angles, valve seat configuration, and port spacing of the R07 cylinder head. The R07 also contains a more prominent deck surface.

As early as 1999, GM began working on a successor to the SB2 engine. During the 2004 Cup season, NASCAR began holding discussions with key automotive manufacturers about a possible "Engine of the Future," which would coincide with its "Car of Tomorrow" program. While the Engine of the Future talks fizzled away during 2005, they did establish a base for future engine design in NASCAR. Eventually, Nextel Cup Series Director John Darby developed a list of parameters to define the envelope for all manufacturers. Jim Covey, NASCAR engine program manager for GM Racing stated, "We had already started to lay the foundation for a future Chevrolet engine, and we were able to adapt that design to the Chevrolet R07."

Once the program was given the green light, the R07 development team (consisting of Ed Keating and Ron Sperry, who were in charge of cylinder heads and intake manifolds, and Ondrej Tomek, who was responsible for the cylinder block) worked closely with key Chevrolet teams. GM Powertrain and its suppliers had the prototype R07 engine running durability tests on a dyno six months beyond their start date. The main reasons for production of this engine were to produce competitive power, reliability, and improved safety and to reduce costs for Chevy teams.

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From the exhaust flange side of the cylinder head, you can see the mirror port design of the SB2 (below), as opposed to the alternating port design on the R07. The new design facilitates better flow and added heat dissipation.

The R07 made its debut at the Samsung 500 at Texas Motor Speedway this past April. In May, Kevin Harvick made Chevrolet history by scoring the first win for the R07 engine at the Nextel All-Star Challenge at Lowe's Motor Speedway in Charlotte, North Carolina.

Technical Aspects
The R07 maintains the traditional two-valve/pushrod design as it has been since 1955. The R07 displaces a maximum of 358 ci with a maximum cylinder bore diameter of 4.185 inches. The cylinder block is iron cast with internal oil and coolant passages, eliminating the need for most exterior lines (as were run on the SB2). In order to improve coolant circulation, and lessen temperatures at critical locations, the R07 has a bore distance of 4.5 inches (as opposed to the 4.4 inches in the SB2).

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You may be asking yourself why the ports are so small. These are the as-cast heads from GM. Each team spends numerous hours researching and developing special porting techniques to maximize flow numbers (within the rules of course). Porting must be done in a spherical manner; teams may not change the positioning of the port (higher or lower).

The R07 block design uses a six-bolt head bolt pattern as opposed to the traditional five-bolt pattern. This improves head gasket sealing, along with reducing cylinder bore distortion.

The R07's camshaft resides higher in the block than the SB2's, thus allowing for a shorter/stiffer pushrod to be used. This dramatically improves valvetrain geometry at high rpm. The raised camshaft allows room for inboard piston squirters, which spray the underside of the pistons for additional cooling. The camshaft is also isolated from the crankcase in order to lessen windage from oil falling onto the crankshaft, in essence robbing power.

The R07 cylinder heads resemble the LS-series production cylinder heads, which contain alternating exhaust and intake valve configuration (as opposed to the SB2's "mirror port" design). The shallow valve angle provides a more efficient combustion chamber design, which also allows the engine builder some room when achieving the NASCAR-mandated compression ratio of 12:1. The SB2 contained a 12 degree intake valve angle, coupled with an 8 degree exhaust valve angle-the new R07 uses an 11.5 degree intake valve angle with a 7.5 degree exhaust valve angle.

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Our final view of the cylinder heads reveals the intake flange. As pictured here, there is not much of a difference in the port locations externally, although they are routed differently internally.

The new Chevy engine uses a dry intake manifold, which has an extended plenum design to help equalize the atomization of fuel between the cylinders. Coolant passes through a separate valley cover. If the positioning of the distributor in the front of the engine throws you off, don't fret-it's still a Bow Tie.

The valve covers are cast aluminum, sealed with an O-ring. These particular units contain integral valvespring oilers, which are pressure fed from passages within the cylinder head, additionally eliminating the need for external oil lines. GM Racing has also added a more efficient water pump design, along with a carbon-fiber front timing cover. These particular engines employ the use of a camshaft beltdrive system.

The R07 also contains a provision for the traditional style diaphragm fuel pump, or a remote-mounted mechanical unit, which is driven by a cable off the rear of the camshaft. The remote unit can be put towards the rear of the car near the fuel cell, enhancing safety in case of an accident.

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One can also see the provision included on the R07 head (pictured here) for the O-ring sealing design of the rocker cover. Notice the less rigid, better flowing cast design incorporated into the R07 head.

Key Players
According to Pat Suhy, GM Racing Group Manager, Oval Track, "Chevy NASCAR teams were deeply involved in the design of the Chevrolet R07. We meet monthly with representatives from our four key partners-Hendrick Motorsports, Richard Childress Racing, Joe Gibbs Racing and Dale Earnhardt Inc.-to get their input on how we can make Chevrolet racing engines more reliable and easier to build and service. Many of their ideas were incorporated in the R07's final design, such as the integration of the oil and cooling systems."

GM Racing's mission is to provide premium quality, easy-to-use components, so that Chevy teams can spend more time testing, making power advances and preparing engines.

A large amount of the steps taken by GM Racing engineers to develop the R07 engine are also used to develop GM production type engines. While the R07 may seem like it can power the Space Shuttle, let it be known that similar steps are taken to power your street-driven Bow Tie.

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Here we have the R07 intake manifold. GM Racing has extended the plenum to help equalize fuel distribution amongst the cylinders.

The Future
Now we don't know how likely the R07 engine casting technology will trickle down to production vehicle status, but we can speculate all we want. While taking a look, this engine has some similarities to the popular LS-style engine, along with the overhead valve design dating back to the first ever small-block in 1955. We're already starting to see SB2 NASCAR heads finding their way onto street and race small-blocks, so the day may come when you'll be able to get your hands on one of these.

Just in case you're wondering about all those SB2 engines, no, they are not being scrapped for boat anchors. They have been passed on for use in the Busch Series and Craftsman truck series. However, we're sure the market will eventually be flooded with NASCAR Monte Carlo SS rollers as the teams will make a full-time switch to the "Car of Tomorrow" Impala SS for the 2008 season.

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Racing Relations: Do NASCAR Teams Benefit From The Products They Endorse?
During a recent trip to Richard Childress Racing in North Carolina, we learned of some new technology, how the job gets done, and the actual benefits included in the big dollar endorsements. Many people wonder if teams actually use the products in which they endorse week in and week out. Now some answers are simple. You can be sure Clint Bowyer (car #07) does not hit a bottle of Jack Daniels before strapping in for a 500-miler. And it's doubtful that the car will fire with a tank full of JD.

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While touring through the facility, we were introduced to a 7-Post Shaker. RCR was the first Cup team to own one of these units. This machine can actually simulate an entire race in order to aid in the setup of a car before even leaving the garage. Sounds easy, huh? It's not. All data needs to be programmed into the computer for each individual track based on past experience.

In October of 2006, Shell Oil Company announced its return to NASCAR with a multi-year sponsorship of Richard Childress Racing (RCR). Shell and Pennzoil brands are prominently displayed on the #29 car driven by Kevin Harvick during the '07 NASCAR Nextel Cup series. Shell will also be the associate sponsor of the remaining RCR teams, including Jeff Burton (car #31) and Clint Bowyer (car #07).

Shell lubricant brands include Pennzoil, Quaker State and Rotella T. All of these brands have been active in NASCAR for many decades with teams such as DEI, Roush Racing and Hendrick Motorsports.

During a recent visit to RCR, we had a brief discussion with Mark D. Ferner, Principal Technologist and Team Leader of Shell Global Solutions, and Rick Mann, Chief Engine Builder at RCR.

According to Mark, "All of the research and development at Shell takes place in its Houston, Texas, facility. Special synthetic formulations are blended specifically for RCR according to feedback from the team on areas of concern. Main components within the blend include wear and friction modifiers. Formulations can be changed and ready within one week. RCR currently uses a synthetic blend containing 75-80 percent base stock."

We asked Mark about adaptive molecules and he replied, "Adaptive molecules are viscosity index improvers, which help prevent viscosity breakdown," he said. "It's the spaghetti theory: Regular oil is like strands of spaghetti, as they go through tight areas they keep shredding apart into smaller pieces (viscosity breakdown), while adaptive molecules are like Koosh balls with many tentacles. As the Koosh balls enter tight areas they will lose some tentacles, but reattach once out in the open."

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Here's the No. 29 Monte Carlo SS of Kevin Harvick. We snagged a photo just before the team loaded it into the trailer for the Brickyard race in Indy. This had a one-time Reese's paint scheme for the race.

According to Mann, "RCR is very happy with its partnership with Shell. Two main things that are checked in an engine are component wear and particles caught within the oil filter. RCR uses 0w-30-weight oil without a restrictor plate, and 0w-20-weight during restrictor plate racing. A fresh filter and oil are always used before a Sunday race. The R07 engine contains six gallons of oil within the dry-sump system (two more quarts than the SB2). During break-in procedures, RCR uses Rotella T 10w-30-weight oil for its high zinc content. RCR also employs the use of Shell assembly lubes and cleaners in the shop area."

At this time, oil employed on a race weekend is not tested in a lab, although it may be in the future. Since engine wear is not an issue, there is no need for it at this time. Main components checked are weld of piston rings, wrist pin wear and valvespring retainer wear. Combining the new R07's durability and Pennzoil's formulations, engine issues have been kept to a minimum. While RCR receives special formulations from Pennzoil for racing purposes, it is not all that different from the oil available to the general public.

Sources

General Motors
http://www.gm.com
Pennzoil
800-237-8645
http://www.pennzoil.com
Shell Oil Company
Houston, TX 77252
Richard Childress Racing
www.rcrracing.com
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