There is no denying that crate motors are now a big part of stock car racing. The lower initial cost of a sealed crate motor-versus a built race engine-has allowed many new racers to find their way into the sport and made racing just a bit more affordable for veterans.
So far, Chevrolet has been the 800-pound gorilla in the crate motor market. To its credit, the company was the first on the scene with a viable crate motor that could be raced economically. Chevrolet has made its crate motors readily available, and they make good power. Since crate classes began gaining acceptance a few years ago, Chevrolet's 602 and 604 oval track crate motors have been so dominant that they've practically become the only options available. That's too bad, because part of the fun of racing is enjoying the competition between the sport's two major players, Ford and Chevrolet. Without Ford in the mix, it always seemed like something was missing in the crate motor classes.
Hopefully, all of that is about to change with the introduction of Ford's newest circle-track-specific sealed crate motor. This is Ford's second attempt at a racing crate engine, and quite a few changes have been made to make this engine more attractive to racers. Also, while Ford's new motor has the same out-put figures as the Chevrolet crate engine (sanctioning bodies would never accept the engine if it were more powerful than Chevy's offering), its design is a departure from what you might see in a Chevy crate motor.
"We're in a bit of a different situation than Chevrolet when it comes to producing crate motors," explains Jesse Kershaw of Ford Racing Performance Parts. "A cam-in-block V-8 isn't an engine configuration in any of our cars or trucks anymore, so to build a race motor like this, we can't simply pull one off of the assembly line.
"This means we have to go with parts out of our Performance Parts catalog and supplement them with some select aftermarket parts. Because of this, we know we won't be able to build the least expensive crate motor available, but we do feel we are offering one of the most economical engines because of the durability that comes from the high-quality parts used. Still, there's nothing exotic here. All the components are off-the-shelf, and costs have been contained pretty well."
Ford is actually producing two new crate motors. One of them is a a 347 based on a 302 block with a shorter deck height. This is an interesting piece but not as likely to be accepted by circle track sanctioning bodies because the 302 block gives the engine a lower center of gravity than comparable Chevy 350s. The motor that caught our eye is Ford's Z351SR, which is based on a 351 Windsor block. Ford's list price for this sealed crate motor is going to be somewhere around $7,700, but the street price will likely be below $7,300. That sounds like a lot, but when we got the opportunity to dig into one, we were genuinely impressed by the quality of the components used throughout the build. For example, full-roller aluminum rockers are used where you might expect to find cheap stamped-steel units. The combustion chambers in the cylinder heads are CNC-cut for consistency from one engine to the next. And a performance damper is used that is a lot less likely to slip and cause timing problems than a stock damper. These are the kinds of touches that just might give Ford loyalists racing in the crate motor classes an opportunity to return to the Blue Oval.
Ford Racing is attempting...
Ford Racing is attempting to make its entry into sealed motor stock car racing classes.
The engine is sealed by these...
The engine is sealed by these two-piece caps over specific bolts. The bolt slides through a hole in the bottom half of the cap. Once the bolt is properly torqued into place, the top half of the cap is popped in. The top half of the cap is designed so that once in place, it cannot be removed without distorting the metal. This should make it easy for a tech man to spot an engine that has been tampered with. Caps are used on the front cover (so you can't get the camshaft out), the intake manifold (so you can't get the intake or heads off), and the oil pan (so you can't get to the crank or rods).
Thanks to the aluminum heads,...
Thanks to the aluminum heads, our motor weighed in at a svelte 475 pounds.
High-rise Ford Racing valve...
High-rise Ford Racing valve covers are necessary to clear the full-race rocker arms housed beneath. They are cast instead of stamped to stand up to abuse without bending and arrive already vented. All you need to do is add the cover of your choice.
The rocker arms are full-roller...
The rocker arms are full-roller aluminum units (manufactured by Crane but marked as Ford Racing). The ratio for both intakes and exhausts is 1.65:1. Total valve lift is 0.822 for the intakes and 0.842 for the exhausts. The intake rocker arm uses an offset pushrod cup to clean up the geometry. Two rockers on each bank of heads require grinding to clear the corners of the valve covers. We spoke with several engine builders who agreed that this is common practice with aluminum rockers in Ford motors. It isn't a concern as long as the grinding isn't excessive. Crane will be modifying the rockers specifically for this engine, making the clearancing much less noticeable.
Ford is using lightweight...
Ford is using lightweight beehive springs that Kershaw says help limit valve float up to 6,300 rpm, even with the hydraulic roller lifters.
The block is Ford's Sportsman...
The block is Ford's Sportsman casting, which is normally built with flat-tappet lifters. The roller lifters use a retrofit kit. A "dog bone" between each pair of lifters prevents spinning, and a valley tray "spider" holds the entire assembly in place. This is a common practice when upgrading street motors to roller lifters and should work well in this arena, too.
A nice touch is the ARP studs...
A nice touch is the ARP studs used to hold the heads to the block. Studs provide a more uniform clamping force across the head and aid in sealing the combustion chambers. ARP bolts are also used to secure the rod caps.
Ford uses a performance damper...
Ford uses a performance damper that should maintain tolerances under high-rpm racing applications. A flywheel isn't included, and since the engine is internally balanced, you will need a flywheel with zero balance.
"Chevrolet's crate motors are the baseline for all the sanctioning bodies and racetracks," Kershaw says, "so we knew we needed to match those power numbers if we were going to be accepted. That made our goal when designing this engine right at 410 horsepower, which is something we can achieve very easily with an engine this size. So once we hit that power goal we began experimenting with different camshafts to achieve the absolutely flattest horsepower and torque curves possible. I don't want to tip our hand too much, but we've had very good results. This motor makes close to the horsepower goal across a very wide rpm range, which makes it very driveable and will make power all over the racetrack."
To find more for ourselves, we got our hands on one of the first production models ready for service and immediately tore it down to its component pieces. There will be at least one component change-and possibly more-by the time you read this, and overall, we are pleased with the quality throughout. Kershaw says the engines are assembled at a facility in Texas that is dedicated to Ford's performance engines. They are not individually dyno'd, but each Z351SR is cranked and run on a test stand after assembly for approximately 20 minutes to make sure there are no mechanical problems, oil leaks, or other warning signs. We haven't had a chance to dyno this new motor yet, but what we've found so far is pretty interesting. Check out what we found when we took it apart.
|THE SPEC SHEET |
|Engine: ||Z351SR sealed racing crate motor |
|Displacement: ||351 ci |
|Bore: ||4.0" |
|Stroke: ||3.5" |
|Deck Height: ||9.500" |
|Horsepower: ||415 |
|Cylinder Heads: ||Z304 Aluminum |
|Valves: ||Steel 2.02" interior/1.60" exterior |
|Ports: ||204 cc interior/85 cc as-cast |
|Combustion Chambers: ||63 cc CNC |
|Rocker Studs: ||Screw-in |
|Rocker Arms: ||1.65:1 aluminum full roller |
|Pushrods: ||7.850" length, 51/416" diameter, 0.080" wall |
|Camshaft: ||Hydraulic roller |
|Duration: ||226 interior/228 exterior |
|Lobe Lift: ||0.498 interior/0.510 exterior |
|Valvesprings: ||Beehive |
|Retainers: ||Steel |
|Crank: ||Forged steel |
|Main Journals: ||3.00" |
|Connecting Rods: ||5.956" length, forged steel |
|Rod Journals: ||2.310" |
|Pistons: ||Forged flat-top w/coated skirts |
|Intake: ||Aluminum high-rise, single-plane |
|Distributor: ||None |
|Oiling: ||Wet sump |
|Oil Pan: ||Rear sump w/kickouts and windage tray |
The cylinder heads are Ford's...
The cylinder heads are Ford's highly efficient "Z" heads. They are already popular with hot rodders and should work well here. They feature angled plugs, 63cc CNC-cut combustion chambers, and relatively small ports that still flow well for good throttle response on the racetrack. Valves are steel, and the standard size for stock car racing is 2.020 inches for the intake and 1.600 for the exhaust. Since no modifications are allowed to sealed motors, the CNC-cut chambers are a nice touch. They should help ensure consistent power from one engine to the next.
Each engine is run on a test...
Each engine is run on a test stand before leaving the factory, but since no fuel pump is included with the package, we doubt one is bolted up for the test run. During our teardown, we noticed that the fuel pump drive eccentric attached to the front of the timing set appeared to be dry. This isn't really a problem. Just use plenty of assembly lube on the fuel pump's lever when you install one.
The large-capacity oil pan...
The large-capacity oil pan is fully gated and uses a windage "strip" to guide oil into the sump.
Although there is nothing...
Although there is nothing you can do about it in a sealed engine, this may be something to keep an eye on. The camshaft appears to be hardened billet steel while the camshaft thrust plate is standard Ford-issue cast. Normally, these thrust plates are matched with a cast camshaft, which doesn't cause wear issues, but a billet steel cam can eat through these plates relatively quickly. This isn't necessarily a red flag, but it will be interesting to see how well these hold up.
The cam is ground by Crane...
The cam is ground by Crane and features durations of 226/228 and lobe lifts of 0.498 and 0.510 on the intakes and exhausts.
Engine oiling is standard...
Engine oiling is standard wet sump. We checked the pickup, and it seems well-matched on our engine.
The main caps are cast and...
The main caps are cast and use two bolts. With only 410 peak horsepower, it should be more than strong enough.
The flat-top pistons are forgings...
The flat-top pistons are forgings from Mahle. They have a good, modern design with small slipper skirts and narrow wristpins to minimize weight. The skirts have also been treated to Mahle's proprietary anti-friction coating. The pins are 2.280 inches long with a diameter of 0.927 inch. They are fully floating, and wire locks hold them in position instead of spiral locks, which can cause damage to the piston if the engine experiences detonation.
The crank is sourced from...
The crank is sourced from Eagle along with the connecting rods. Although both use all the standard Ford dimensions, they are forged pieces that should hold up well to the rigors of racing.
The single-plane, high-rise...
The single-plane, high-rise manifold will obviously flow well. The large air gap between the runners and the valley cover should help insulate the incoming air/fuel charge from the engine's heat.