© 2017 Power Automedia. all rights reserved.

Project Number Cruncher is our first attempt to build a car destined for intense scaffolding activities. Firebird will be powered by a 427 cubic inch LS, which SAM Tech students use top-of-the-line parts to assemble. Today, we will look at the parts we use for short engine blocks and why we chose them.

Bracket Race is about consistency and repeatability, so it's important to exclude as many variables from the equation as possible. We want to make an engine that does not require a lot of maintenance but can still generate enough power. We did not make a typical small Chevrolet, but cooperated with Dart to create a healthy, naturally aspirated LS engine that does not use any exotic parts.

The students of SAM Tech are taught how to properly prepare the blocks before starting to build the engine.

The next part of the equation is to find an engine manufacturer for this job. SAM Tech has extensive LS engine experience and is training future engine manufacturers. Jimmy Stray of SAM Tech explained how the school worked with students to build this building.

"Whenever we consider building a new project, the first thing to consider is the application of the engine and the required horsepower level. This will give us a good understanding of the level of components required to meet and exceed performance expectations. The school's goal is to Next-generation engine manufacturers teach the skills needed to manufacture high-quality performance engines that not only exceed the owners' expectations, but also stand the test of time in terms of service life. This is the main goal of Number Cruncher, starting from short block assembly. solid foundation."

Project Number Cruncher's LS engine is based on Dart's cast iron LSNEXT block. In the previous article, we introduced the advantages of this block and why we chose to use it. The aftermarket block provides SAM Tech with the perfect canvas to start building the engine.

SAM Tech first installs the ARP main stud in place and completes the corresponding machine work. The purpose of this is to ensure that everything is round and straight. The ARP studs will ensure that the cap is firmly fixed. This process will also ensure that the linear motion of the piston and crankshaft rotational motion is optimized.

The ARP stud helps to hold the Dart crank in place so that it can rotate freely on the MAHLE main bearings.

Andrew Hachmeister of SAM Tech explains the other items handled during block processing.

"After adding the studs to the cylinder body and grinding it flat, we machined the cylinder bore to the final size. Through Dart's precision machining, our actual machining time has been reduced by this process. A very important part of the honing process is the cylinder. Degree and creating the proper surface finish-sealing is the name of the game. Finally, we surfaced the block to achieve the proper deck clearance, and together with the cylinder head gasket we chose, provided us with the quenching we wanted."

After the block is completed, SAM Tech continues to prepare the crankshaft and bearings. For the backbone of this sturdy LS engine, we decided to use a Dart billet CCW crankshaft. CCW stands for center weight, which is the exact reason we chose this crank. The CCW crank is ideal for high RPM applications because it can stiffen the crankshaft and reduce the degree of crankshaft bending. This means that the crank will not start "skipping" under high RPM or horsepower loads. This will prevent it from walking inside the main cap and causing problems.

The crank stroke we used is 4.000 inches, 58-tooth reluctance wheels, a total of eight weights have been added, and they are made of 4340 blanks. Dart also added heavy-duty rod cheeks and small holes through the rod pins, the crank is roughly balanced to 1780 grams, and does not require any Mallory (Mallory 300 is an alloy commonly used for crankshaft balancing).

After the Dart crank was balanced, it was placed in a new home in the iron Dart block of Number Cruncher.

"We decided to use a central counterweight crank in this version, partly because of the amount of RPM we will turn. The correct crank is very important, especially when your speed exceeds 7,000 RPM. Choosing a central counterweight will increase the life of the engine. More reliable. The crankshaft gave us a rough balance, so we incorporated it into the appropriate specifications we need based on the weight of the components. We polished the journal again and cleaned the crank before installation. After checking all the bearing clearances, Tighten the ARP stud one last time," Hachmeister said.

Bearings play an important role in how the engine is assembled and operated, so you need to make sure that the bearings you choose are suitable for your application tasks. We have selected a full set of MAHLE bearings in this version; these have no problems in handling the horsepower or cylinder pressure we are going to put in.

Dan Begle of MAHLE provided some insights on why good bearings are essential in such high-performance construction.

"Compared with standard replacement bearings, high-performance bearings can withstand higher load ratings and crank deflection, while covering less fatigue. High-performance bearings are also designed to provide greater squeezing force. This is important because the crank will Deflection due to torsional load... it will want to move the main bearing."

Begle delved into the reasons for bearing crushing and the importance of oil film.

"Increasing the squeeze will maximize the clamping load of the main hole to prevent this movement. It is very important to have bearings designed to improve the oil film and maintain the oil film like a high-performance bearing. As the load increases, the oil film may be affected. This can cause the bearing to seize. It is important to have bearings with higher seizure resistance and load-carrying capacity."

Rods, pistons, rings and fasteners

The K1 6.125 connecting rod selected by SAM Tech is very suitable for this engine configuration.

The connecting rods selected by SAM Tech for Project Number Cruncher are not unusual parts, they are actually off-the-shelf K1 6.125 inch connecting rods. SAM Tech has assembled a large number of record-setting all-electric and supercharged LS engines, so there is no doubt that this choice will work. These rods checked each box of our target with the engine.

"K1 provides a very good connecting rod-they will be fully within our power range, and can withstand the RPM we are going to turn the engine. Because of its strength and weight, it is not only a good rod for the application, but also the tolerance It also meets the standards we want to see," Hachmeister said.

 The bolt must keep the cap on the rod. The clamping load generated by the properly installed rod bolt must exceed the dynamic load seen by the cap at maximum RPM. – Chris Raschke, ARP

High-winding naturally aspirated engines that produce a lot of steam will withstand different loads and forces. This is why it is so important to choose the right rod for the application and make sure you use the right fasteners. Matt Polena from K1 added some additional information explaining why SAM Tech uses this special pole and is faster.

To ensure that the K1 rods are held in place, a full set of ARP fasteners are used on each rod.

"Naturally aspirated engines will see a large amount of loading and unloading of the connecting rod, resulting in a large pulling force on the connecting rod. The K1 rod is forged from 4340 steel and is shot peened to improve fatigue life. Thick blades to help minimize outward bending under peak combustion pressure. Since the connecting rod bolts are the most stressed fasteners in the engine, the inclusion of ARP 2000 series bolts in the K1 rod is for high-horsepower NA like this It's a big benefit in terms of construction," Polena explained.

Project Number Cruncher’s ARP hardware is provided by Summit Racing Equipment; even during the global pandemic summit, we have everything we need to fasten this short block with the correct fasteners. Summit not only sells parts, the company can also answer any questions you have about the parts you need. Joe Fishel of Summit Racing Equipment added some additional information on why it is so important to use the correct fasteners when installing connecting rods.

"High-quality fasteners are a necessary condition for the manufacture of any high-horsepower engine. The stress on the connecting rod does not come from the cylinder pressure, but from the extreme reciprocating load at high speeds. Thanks to the ARP rod bolts, the main cap is firmly clamped And it starts to take an oval shape. This prevents the rod bearing from malfunctioning and prevents you from throwing the rod from the side of the block," Fisher said.

SAM not only bolted the K1 rod to the Dart crankshaft before moving it during the assembly process. Before installing the rod, students must do some preparation work, which is a key step to ensure that there is no problem after the engine is completed.

During the final assembly of the rotating components, SAM Tech students ensure that each tolerance and measurement value is triple checked.

"Before we install the rod bearings, first we must make sure that the housing dimensions are the correct size. After we confirmed that they are the correct specifications, we installed the bearings and checked the vertical oil gap to ensure that there would be no problems. Once all the gaps are matched , We clean the crank journal and the bearing for the last time, then use VP assembly lubricant between the bearing and the crank, and finally, we unscrew the ARP bolts,” Hachmeister explained.

 Generally, for N/A engines, we want the piston to run with as little clearance as possible and shake as little as possible. Vic Ehringer, Wiseco

This version of the Wiseco piston is the only custom part that needs to be used. Customizing custom pistons for such engines is a good idea because they can be tailored to the application based on the dome design, compression, and skirt that SAM wants to see. These areas are important because they allow SAM to further optimize the engine to produce maximum horsepower.

"Getting a custom set of pistons is especially important for a naturally aspirated construction. There is no external source that allows you to generate more power. Since the engine is a naturally aspirated engine, the parts need to be light and efficient to work together. Wiseco's Experience makes it possible to decide what is safe by reducing the weight of the piston, so strength is not sacrificed," Hachmeister said.

The custom-designed piston created by Wiseco will help optimize the combustion process in the engine cylinder.

Vic Ellinger from Wiseco provided some background on designing pistons, as he created for the engine of Project Number Cruncher.

“For a naturally aspirated engine, compared to an engine with a power adder, the gap between the piston and the wall is usually smaller because it generates less heat and horsepower,” explains Ellinger. "The barrel and cam incorporated into the piston shape can sometimes be more aggressive and have less expansion. This helps stabilize the piston better, which in turn increases ring seals and reduces wear."

The last piece of the piston puzzle of the Project Number Cruncher engine is the piston ring. SAM Tech chose to use the combination of 1mm, 1mm, 2mm and top ring with air port from Total Seal. After checking the stroke length of the engine and the target RPM level to determine the piston speed, the ring package was selected.

The Total Seal ring package selected by SAM Tech is designed for use with high-horsepower N/A engines.

Lake Speed ​​by Total Seal explains why this ring kit is suitable for this specific engine kit.

"If there is no power adder, the naturally aspirated engine must operate efficiently to maximize the power output per cubic inch. The 1 mm, 1 mm, 2 mm ring kit is a sporty but conservative ring kit, suitable for It is lighter than the N/A engine. It is light enough to achieve high RPM, which allows the N/A engine to stretch its legs. This is very important because more than 40% of engine friction comes from the friction between the piston ring and the cylinder bore, and the engine friction follows The increase in RPM increases. Therefore, the use of a thinner, lower tension ring can release horsepower, allowing the engine to generate more power at a higher RPM. All of this improves engine efficiency."

The high-horsepower LS engine has a very high oil injection requirement, so you need to make sure that your pumps and discs can pass a large amount of oil. SAM Tech decided to use the Melling 10294 high-performance oil pump for this construction because of its properties suitable for this application. The Dart block that we use as the basis for this engine presents a specific set of requirements that need to be addressed to prevent oil injection problems.

Mike Osterhaus from Melling explains why this pump was created.

"Engine manufacturers using Dart LS Next with standard bearing clearance can see high oil pressure when using the Melling 10295 oil pump. When the Dart block was released, the engine manufacturer modified the oil pump in some way to reduce The amount of oil coming out," Osterhaus said. "In order to properly solve this problem, Melling released the 10294, a low-capacity standard pressure oil pump. The 10294 provides 15% less oil flow than the 10295, and can only be used with the after-sales block with priority main oil injection. 10294 comes with optional The 10 and 25 psi pressure springs are packaged with the pump to increase the pressure setting of the pump. The 25 psi spring is designed to match the pressure setting of the GM COPO Camaro LSX engine."

All the oil flowing through the engine needs a place when not in use. This is the source of the oil pan. High-horsepower N/A cars must have an oil pan specially designed for use with the engine. It takes a lot of work to ensure that the engine oil reaches the right place at the right time.

"Having a suitable oil pan will have some major effects on the oil. The correct design can not only drain the oil from the rotating parts by kicking out, but also produce better oil quality and reduce aeration. The baffle is very important, It needs to be matched to the application of the engine. They keep the oil in an enclosed area to provide a continuous oil supply as you drive, brake and turn along the track," Hachmeister said.

Moroso makes some of the best oil pans on the market, and luckily they have an oil pan that can be used with our Dart block. Thor Schroeder from Moroso explained the company's perspective when designing the kind of smooth oil pan we are using.

"A good oil pan for N/A engines will release horsepower while reducing the oil temperature by effectively removing the oil from the crank, and keeping it away from the crank after removing the oil. This is why many high-performance engine manufacturers require a After-sales oil pan with extra oil capacity, internal anti-shake baffle, trap door baffle to control oil sloshing in the oil pan, and a power kick/bag. The power output/bag is a skirtless engine oil pan An area on the side that allows the oil vapor in the crank to escape; this will release horsepower and help lower the oil temperature."

This is the final product, a killer 427 cubic inch short block, which should generate some powerful power when completed.

Now that SAM Tech has the bottom end of Project Number Cruncher LS, it's time to get to the top. In our next article, we will describe the process of completing the engine before fixing it between the Firebird's fenders. Be sure to check the Project Number Cruncher build page here to understand the entire build process of this bracket racing machine.

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