Though this year's Engine Challenge was far from routine for engine builder Scott Schurbon
To see video of Schurbon's dyno run click here.
As last year's runner-up finisher, Schurbon Engine and Machine made impressive power with their Magnum-headed stroker small-block, finishing second only to the somewhat exotic entry of Indy Cylinder Head. So as this year's Amsoil/Mopar Muscle Engine Challenge began, everyone was eager to see how the 440 built by Schurbon Engine and Machine would perform in the 2008 contest. Unfortunately, a series of unplanned events would keep us from seeing the true potential of this motor. Even so, the Schurbon engine made an impressive 654.8 hp and 568 lb/ft of torque on Rockett Brand 93 octane pump fuel, for a combined score of 1223.8 and a sixth place finish. Had the engine not been damaged on its first pull, we're sure these numbers would have been higher, making Schurbon a contender for a better finish, but this year the deck just seemed to be stacked against engine builder Scott Schurbon.
The problems encountered by Schurbon Engine and Machine this year began well before their engine was bolted to Comp's dyno in September. In fact, shortly after Scott assigned the Challenge 440 to his top engine builder Devin Sievels, Devin was tragically killed in a motorcycle accident on April 5, 2008. The loss of Devin affected everyone at Schurbon Engine and Machine as they lost not only a valuable employee, but a close friend. As an experienced race-engine builder, Devin had big plans for this 440 and energetically began the project. Unfortunately, Devin didn't survive to see the fruits of his labor as the 440 was in the preliminary stages at the time of his death. Struggling to regain Devin's excitement, Scott and the rest of the crew at Schurbon pitched in to finish the engine in his honor, but struggled emotionally due to the loss of their coworker and friend. Pressing on, they did complete the engine just in time for a dyno test session, but then had to repair the engine on the dyno, barely making the drop-off deadline of last year's Mopar Nationals.
Once at Comp for our dyno session, Scott was optimistic about his entry, but we could tell the emotional impact of losing an employee and friend was bothering him. Wishing Devin could have completed this engine, and wanting the entry to perform well, Scott had a lot on his mind and inadvertently set the engine's timing to 64 degrees total advance for its first pull. During the pull the engine sounded ok, but something was off as it didn't make the power it should have. Checking the timing again for the second pull, Scott quickly realized his mistake and corrected it, but the damage was already done. Rather than blaming the equipment or circumstances, Scott took full responsibility for the error and felt terrible because of all the work his employees put into the motor. Luckily, the engine survived to make all the required pulls, though the post-dyno teardown revealed two blown head gaskets and several pinched compression rings due to heavy detonation induced by the improper ignition timing. Even so, the 440 made an impressive 654.8 hp and 569 lb/ft of torque. We can only speculate as to how much power this engine would have made if it were healthy, but we're sure it would have certainly finished better than sixth place.
After being bolted to Comp's dyno, the Schurbon entry fired up and sounded crisp. This eng
After a misread of the adjustable timing light, Scott mistakenly set the ignition timing a
Subsequently, Scott used the timing light to look at the oil through his way-cool, clear L
Having lost his top engine builder and friend Devin Sievels to an unfortunate motorcycle a
Though Scott was a good sport about his mistake, we know that he's actually very serious about his work. Scott is an accomplished and professional engine builder having placed second only to Indy Cylinder Head in last year's competition, and the employees of Schurbon Engine and Machine are equally as dedicated to their profession. This year the 440 they entered in our contest would have certainly been a top contender had it not been damaged during its first pull. While Scott claims there's no excuse for his mistake, to us it serves as a good example of how stress and unfamiliar equipment can cause even a true professional to make an error. As we evaluate the Schurbon Engine and Machine entry in this month's issue, remember that the power numbers don't indicate the true potential of this engine, nor are they indicative of Scott's abilities.
...the crew from Schurbon Engine and Machine finished the engine in Devin's honor.
Starting with a seasoned factory 440 block, Schurbon Engine and Machine performed all the necessary machine work in-house, squaring and decking the block and boring it .060 inch oversize. For a strong rotating assembly, Schurbon utilized an RPM forged steel crankshaft and RPM I-beam forged steel connecting rods along with Probe forged pistons. Total Seal Piston Rings were used to seal the cylinders, and Fel-Pro gaskets and seals kept the oil and coolant where it was supposed to be. Clevite bearings were utilized throughout the engine, and a Melling oil pump was combined with a Moroso pan and fabricated windage tray to keep everything lubricated with Amsoil synthetic oil. A Chenoweth main stud girdle was also employed, giving the mains extra support, and ARP studs and fasteners were used throughout the engine. When picking a camshaft, engine builder Scott Schurbon enlisted the help of the Comp Cams engineering department to help recommend a solid-roller camshaft for this application. The cam they chose had nearly .800 inch intake and exhaust lift with 271/279 degrees of duration at .050 inch lift respectively, and was spun by an Engine Pro timing chain and gears.
Sensing engine builder Scott Schurbon's frustration, the crew from Chenoweth Speed and Mac
Topping this stout 440, Schurbon Engine and Machine utilized the same Indy SR aluminum cylinder heads that our rules required each builder to use. Starting with the bare CNC castings, the heads were ported and flowed in-house for optimum performance. Knowing the loss suffered by Schurbon, engine builder David Bruns of Mid-America Racing Engines graciously offered his time to help with the cylinder head porting. Ferrea 2.19-inch intake and 1.88-inch stainless steel exhaust valves were installed after the port work was finished and Comp Cams springs, retainer, and locks were utilized. PRW roller rocker arms were used for their strength, durability, and relative low cost. For induction, an Edelbrock Super Victor single-plane aluminum intake manifold was installed, and a modified Holley Dominator handled mixing the fuel and air. To ignite the mixture, an MSD Pro-Billet distributor and Super Conductor plug wires were used for their proven performance.
Editor's Note: In the May issue, we incorrectly stated that the cylinder head porting performed on the Chenoweth Speed and Machine entry was accomplished by Indy Cylinder Head. The CNC porting was actually performed by Jeff Kobylski of Modern Cylinder Head. Additionally, the camshaft in the Chenoweth's engine was changed just before the engine was delivered to a custom grind recommended by Comp Cams engineer Chris Padgett. The actual specs of the camshaft are .269 degrees on the intake, and .280 degrees of duration on the exhaust at .050 inch lift, with .800 inch lift on the intake and .772 inch lift exhaust.
|Indy Cylinder Head||Schurbon Engine and Machine|
|Indianapolis, IN 46239||Maquoketa, IA, 52060|
|JMS Racing Engines||JD Engine and Machine|
|El Monte, CA, 91732||Columbia, MO, 65203|
|Chenoweth Speed and Machine||Cederstrand Racing Engines|
|Morton, IL, 61550||Brea, CA, 92821|
|Indianapolis, IN 46222|
Our rules limited the oil pan that could be used but didn't say anything about putting a s
Everyone was eager to see how much power last year's runner-up would make. Though his engi
A custom windage tray was fabricated in-house, and the oil pickup had to be extended to re
A main stud girdle from Chenoweth Speed and Machine helps to strengthen the bottom end of
Topping their .060 over 440, Schurbon utilized the same Indy Cylinder Head SR castings tha
Engine builder Scott Schurbon chose RPM I-beam connecting rods for their great strength to
Starting with Indy's non-ported CNC castings, the heads were ported in-house at Schurbon E
With a cylinder head removed for the post-dyno inspection, the damage inflicted by detonat
Both head gaskets were blown in several places, and you can see in the picture on the left
From below, you can see the cam tunnel that Schurbon used to further reduce windage. This
In this shot you can see that the head gasket was actually pushed upward, elongating the h
Edelbrock's new Super Victor intake manifold was tested along with several other intake ma
Scott Schurbon used two different carb spacers, but found that two, two-inch spacers, for
PRW roller tip rocker arms were used in the Schurbon 440. For the price, engine builder Sc
Limited to 1,350 cfm by our rules, Schurbon chose a Holley 1150 Dominator carb, modifying
Battling adversity, Schurbon Engine and Machine made a good showing at this year's Engine