How To Build An LS Engine: Short Block Assembly Part 2

Bare Block Performance Package

Part 2: Wrapping Up the Rotating Assembly on Our Summit Racing 5.3 Iron Block Engine Package

By Ryan Manson   –   Photography By Brian Brennan   –   Videography by Ryan Foss

For Part 1, click here.

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Thorough block inspection is paramount to a successful performance engine build, and Kyle Martelli and the team at American Heritage Performance’s (AHP) attention to detail will no doubt show through when we put our LS engine through its paces on AHP’s dyno. But before that can happen, we need to continue with the assembly process, starting with the rotating assembly.

02 prep rotating assembly inspecting tolerances
We wrapped up the last story with a clean and inspected iron block and the Summit Racing 3.622-inch stroked crank in place. The next step is to prep our rotating assembly, once again inspecting all tolerances.

To continue with our Summit build, it should come as no surprise that we chose to use their LS Pro line of products for nearly all the moving parts in our motor. Starting with their 6.125-inch H-beam connecting rods and concluding with a set of their forged 2618 alloy pistons, the top end of our LS is a complete assembly of Summit Racing LS Pro parts. Like the crankshaft installation, Martelli inspected all the components, noted the results, and compared them to the specs provided by Summit and the bearing manufacturer. Pleased with the results, Martelli proceeded to file the ring pack to spec before assembling the piston/rod assembly. From there, using an ARP piston installation tool, Martelli dropped each slug pack into their respective cylinder, torquing every rod cap to spec via ARP 2000 rod bolts.

03 summit racing pro ls line pistons steel wristpins spirolock retainers
For our 330ci build, Martelli and the crew at American Heritage Performance (AHP) chose components from Summit Racing’s Pro LS line. This includes a set of pistons (PN SUM-2999273810-7) forged from premium 2618 alloy, durable Chromium Steel wristpins, and Spirolock retainers.

With the rotating assembly complete, Martelli then turned his attention to the installation of the camshaft. When it came to camshaft selection, we went with recommendations from both the AHP and Summit Racing teams, resulting with another selection from the Summit LS Pro line. Featuring 222 degrees of duration on the intake side and 234 degrees on the exhaust side at 0.050-inch lift, the resulting hydraulic roller tappet camshaft should provide plenty of low-end grunt, a good idle lope, and plenty of top-end power.

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Read More: Sensors You Need To Replace On Your Junkyard LS

From there, Martelli installed the timing chain components and the high-volume oil pump. Front and rear covers were then installed, followed by a stock oil pan, effectively sealing up the bottom end of our short-block build.

04 4340 forged steel pro ls h beam connecting rods
To mate the pistons to the crank, 4340 Forged Steel Pro LS H-beam connecting rods (PN SUM-LS6125927) from Summit will be used. Designed for up to 5,000 ft/min average piston speed, these durable rods feature a 6.125-inch length and will clear most camshafts up to a 4.250-inch stroke. Twelve-point ARP 2000 rod bolts come standard to ensure the rotating assembly remains fixed to the crankshaft.
05 measure piston and note diameter
Having previously balanced the rotating assembly there are still a few inspections that need to be made before Martelli begins assembly. First, each piston is carefully measured and its diameter noted.

06 measure piston and note diameter

07 bore gauge measure cylnder bore
Next, Martelli uses a dial bore gauge to measure each cylinder’s bore. Those specs are then noted and compared to the piston measurements. The pistons are then matched to the most appropriate cylinder to maintain a consistent piston-to-wall clearance around 0.0040 inches for all cylinders.
08 arp 2000 rod bolts torqued to spec
Next, Martelli measures the big end of each connecting rod with the bearings installed and the ARP 2000 rod bolts torqued to spec and compares this number with the diameter of each connecting rod journal on the crankshaft. This provides Martelli with the connecting rod bearing clearances (0.0027 inches).
09 assmebly lube applied to rod small end piston pin piston pin bore
With inspection of the rotating package complete, Martelli begins assembly. First, assembly lube is applied to the con rod’s small end, piston pin, and piston pin bore.

10 assmebly lube applied to rod small end piston pin piston pin bore 11 assmebly lube applied to rod small end piston pin piston pin bore

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12 spirolock pin retainers
Spirolock pin retainers are used to hold the assembly together. Martelli slightly separates the spiral wire before carefully rotating it into position.
13 eight assemblies placed in fixture
All eight assemblies are placed in a fixture according to their respective location in the engine for easy assembly.
14 hastings steel performance piston rings
A set of Hastings steel performance piston rings (Summit PN SM8531035) will be used to control the oil and compression, but the two top compression rings need to be filed to fit each cylinder before assembly can begin.
15 ring placed squarely in bore before ring endgap is measured
Each ring needs to be placed squarely in the bore before the ring endgap can be measured. A Summit Piston Ring Squaring Tool (PN SME-906002) is a great way to accomplish this.

16 ring placed squarely in bore before ring endgap is measured summit racing piston ring squaring tool

17 ring endgap filed using piston ring filer summit racing
Out of the box, the ring endgap is very small and needs to be filed to fit the cylinder bore using a piston ring filer like this one from Summit Racing (PN SUM-970011).

18 ring endgap filed using piston ring filer summit racing

19 getting the desired endgap
Working slowly, Martelli sneaks up on the magic number for each ring’s endgap, 0.018 inch for the top rings and 0.023 inch for the second rings, carefully deburring the ends as he goes. Each ring must be installed in the bore a handful of times and measured using a feeler gauge until the desired endgap is achieved.
20 installation of the oil control rings
With the compression rings filed to Martelli’s satisfaction, installation of the rings can begin, starting with the oil control rings. First, the spring-like expander ring is installed, followed by the upper and lower rails. Martelli installs the two oil rail rings so that their endgaps are 180 degrees opposite. It should also be noted that the oil rings did not need to be filed to fit.
21 napier style second ring installed
Next, the Napier-style second ring is installed. Martelli ensures that any directional marking is pointed toward the top of the piston before inserting one end of the ring into the ring groove and then carefully rotating it into place.
22 top compression ring installation
The top compression ring is installed in a similar manner. Martelli orients the top ring’s endgap at the top of the piston’s skirt, while the second ring is 180 degrees opposite.
23 dropping slugs into holes oil application to rings and pistons
Once all the rings have been installed, Martelli is ready to begin dropping the slugs into their respective holes. A light coat of oil is applied to the rings and the piston, while a similar coat of assembly lube is applied to the upper and lower connecting rod bearings, before the piston is dropped into the cylinder bore, aided by an ARP piston installation tool.
24 orienting crank rod journal
To provide plenty of clearance for the incoming connecting rod, the crank’s rod journal is oriented at the bottom of its stroke for the respective cylinder that is being assembled. Here, Martelli has lowered the piston assembly into place on the crankshaft before installing the rod cap and fasteners, slightly snug for now. Care is given to ensure the rod bearings are installed with the proper clearance for the crank’s fillet (the radius where the crank’s web meets the rod journal). The rods need to be installed with this fillet in mind as well as they are unidirectional.
25 incremental torque sequence arp 2000 rod bolts
Once all eight cylinders have been assembled, Martelli begins the incremental torque sequence for each pair of ARP 2000 rod bolts, starting at 25 lb-ft and working from there for a final torque spec of 82 lb-ft.
26 torque striping on rod bolts to denote they are properly torqued
Next, Martelli checks the connecting rod side clearance using a feeler gauge. A reading of 0.022 inches between each rod means we’re in the clear. Note the torque striping on the rod bolts to denote that they’ve been properly torqued.
27 new gasket summit pn nal 12639249
We’ll be reusing the stock rear cover, with a new gasket from Summit (PN NAL-12639249). There are two tools that are used to install the front and rear covers to ensure they’re centered with the crank and aligned with the bottom oil rail of the engine block to prevent leaks. Here, the cover is installed with the ARP fasteners finger tight and the crankshaft centering tool in place.
28 tool attached to bottom of engine block
The second tool attaches to the bottom of the engine block and the rear cover and brings them in line with each other. The rear cover fasteners are now torqued to 18 lb-ft.
29 camshaft summit pro ls hydraullic roller tappet campshaft
With the rear cover in place, Martelli turns his attention to the front of the engine and, more precisely, to the camshaft. We’re using a Summit Pro LS hydraulic roller tappet camshaft (PN SUM-8715R1) with 222/234 duration at 0.050-inch lift and a 115-degree lobe separation. Martelli applies camshaft assembly lube to each lobe and bearing surface before carefully installing the camshaft in the block.
30 camshaft retaining plate sum 150106
The camshaft retaining plate (PN SUM-150106) controls the forward movement of the cam and is installed next. A dab of thread locker was applied to each bolt before they were torqued to 11 lb-ft.
31 woodruff keys prevent oil pump and timing gears from rotating on crankshaft snout
Two Woodruff keys are used to prevent the oil pump and timing gears from rotating on the crankshaft’s snout.
32 cloyes crankshaft sprocket clo s827
The Cloyes crankshaft sprocket (PN CLO-S827) serves two functions on the LS-series engines; in addition to acting as a traditional timing gear it also serves to drive the oil pump.
33 gm campshaft sprocket ado 12576407 aligned to single roller timing chain nal 12646386
A GM camshaft sprocket (Summit PN ADO-12576407) is aligned to the crankshaft sprocket and attached via a Chevrolet Performance single-roller timing chain (PN NAL-12646386). Once again, ARP fasteners are used for performance and reliability, torqued to 26 lb-ft.
34 melling performance high volume oil pump mel 10296
Next, it’s time to install the Melling Performance High Volume oil pump (PN MEL-10296). Martelli preps the pump by applying a liberal amount of engine oil inside the pump to prevent cavitation on initial start-up …
35 aligning pump with crankshaft by tightening the fasteners
… before sliding the pump over the crankshaft sprocket. Martelli aligns the pump with the crankshaft by tightening the fasteners slightly snug and rotating the crankshaft 360 degrees, before torquing them to spec.
36 front of block complete
The front of our block is now complete and it’s time to install the front cover.
37 gasket sum g2628 arp hardware gm timing cover
Using a new gasket (Summit PN SUM-G2628), ARP hardware, and similar installation tools as used to install and align the rear cover, Martelli installs the stock GM timing cover.
38 summit racing pro ls oil pan sum 121200
We’re using the stock oil pan, baffle, and pickup for the moment, but clearance issues with the intended vehicle may call for a lower profile pan, such as Summit’s Pro LS oil pan (PN SUM-121200).
39 straightedge alignment of bellhousing and transmissions
Using a straightedge, Martelli ensures that the back of the pan and block are aligned since some bellhousings/transmissions bolt to both surfaces.
40 iron block ls engine fully assembled long block
Our 330ci iron block LS engine is now a fully assembled long-block!

For Part 3, click here.

American Heritage Performance
(310) 326-2399

Automotive Racing Products (ARP)
(800) 826-3045

Summit Racing
(800) 230-3030

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