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LC2 Buttom End Engine Build - Power Trip
With This '87 T, I Want 10s At The Strip, Mild Manners On The Street, And The Kind Of Reliability Needed For An NYC Commute. Will I Pull It Off?
Aug 1, 2006
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LC2 Buttom End Engine Build - Power Trip
After 160,000 brutal, high-boost miles, the LC2 and engine bay look a little ghetto. As you can see here, I've got several good parts on this engine--bigger PTE 44 turbo, bigger stock-location intercooler, MAF Translator Plus with LS1 sensor, Houston downpipe, vacuum brake swap, etc. This current combo was good for low 12s. Believe it or not, I've never cracked this motor open; it retains the same stock internals that it was built with, and it never so much as blew a head gasket. As I liked to run 18 psi on pump gas, and between 23 and 25 pounds on race gas, that's saying something!
Once I started to see some coolant in the oil, the staff over at Ron's Custom Auto in Kenilworth, N.J., offered to yank my hurt motor-- here's Junior pulling it out of the car.
I tore the LC2 down at Ron's Custom, and was amazed not to see any carnage. The head gaskets appeared to be intact, and there was no sign of mechanical failure anywhere. Without Magnafluxing, we're guessing that a head cracked. It was a stock block/iron heads LC2 when it came out, and that's exactly what it will be when we reinstall it. The plan is to make great streetable horsepower and torque with the factory 109 block, stock rods, stock crank, and iron heads. This will be a middle-of-the-road build--we'll be using some premium parts, but we'll try to save money in as many places as possible.
Besides forged pistons, the bottom end of this LC2 will be stock. As such, Hartline Performance arranged to have a block, crank, and set of rods machined to his specs at a local shop. The machining process took place at CRE in Orlando, Fla. CRE decked the block to make sure it was square, then bored and honed it with BHJ deck plates. On the bottom end, the oil pan rail was squared parallel to the crank. The block was also machined to accept RJC Racing's girdle-the caps were milled, then the appropriate shims were installed. The girdle was installed, then the block was align-honed. Note that Hartline Performance requests that each RJC girdle is clearanced for the oil pickup extension.
Here's Cal Hartline, proprietor of Hartline Performance, with the machined block. Hartline Performance puts most of its time into top-quality ECU tuning for a variety of vehicles, and typically doesn't do engine builds, but Cal agreed to put our V-6 together as a favor to us. Hartline is in the process of building a brand-new performance shop, so in the interim this build was done at Felber Race Engineering's clean room in Palm Bay, Fla. You can see that RJC Racing's 1/2-inch main cap studs have already been installed. "Besides the standard 3.8 machining work," Cal starts, "I also like to do some cam bearing oiling tricks during the assembly process. By re-drilling with a smaller .080 hole, it restricts how much oil hits the cam bearings, and redirects it to the bottom end."
Let's discuss part selection: Of utmost importance when building a high-zoot LC2 is head choice--and you don't need to look any further than Champion Racing Heads. Champion has 15-plus years of Buick head work, and its two head offerings, the CNC iron and the CNC GN1 aluminum heads, are the perfect cure for the restrictive stock heads. The $1,600 GN1s will undoubtedly produce more power, but for this build, we'll save a few bucks and go with the Champion irons. These power-producing units are a bargain at $1,195 a set, with no core exchange.
The Champion irons start as reconditioned factory 8445 castings, get the heat riser passage filled, then are fully CNC ported. The chambers, intake ports, and exhaust ports receive extensive CNC work, and the intake and exhaust ports are then hand-finished for max flow. The deck surface is milled for a good head gasket seal. You'll also find that the intake face, the exhaust flange, and the valve cover rail are all machined flat like a brand new head. Other notable features of the Champion heads include machined cro-moly steel retainers, bronze guide liners, Teflon valve stem seals, and heat-treated machined valve locks.
A close-up of a Champion chamber: it receives CNC work, then after the final valve job the chamber is hand-polished to blend in any sharp edges. This allows a smooth transition from the port to the combustion chamber, and eliminates the possibility of detonation, as well as limits turbulence. The 46cc chambers are filled with Ferrea 1.77-inch intake and 1.50-inch exhaust stainless steel valves. This high-flow, 29-degree tulip exhaust valve is custom-made for turbo applications with special alloy to resist high temps.
These iron heads come with 100-pound seat pressure valvesprings for flat-tappet cams, good to .500 lift; for Cal's roller-cam motors, he specs out slightly more aggressive 140-pound valvesprings (shown).
The port work on this intake runner is clearly evident. The runners are recontoured and enlarged for better airflow. As the stock 8445 heads were a big restriction to the LC2's power potential, enhanced flow here will pay huge dividends.
To maximize the performance of its heads, Champion recommends using its GN1 ported OEM intake. Champion cleans up and inspects the stock manifold, then CNCs the port openings to get the exact size/opening to match the heads
Next, Champion fully hand-polishes the port openings and plenum, and welds up the EGR tower for maximum flow.
The cam Hartline specced for this build is a COMP Cams 210/210 hydraulic roller with a 110 LSA. The lobe lift is .317-inch; Valve lift with a stock 1.55 rocker setup would be .491-inch, but since we'll be bolting up T&D's 1.65-ratio rocker arm setup for reliability, actual lift will be .523-inch. This is a nice all-around cam with great street manners.
Mmm, roller cam. When discussing rollers, there are two types to get familiar with: aus-tempered, and billet. Years back econo rollers gave all rollers a bad name, as inferior materials caused them to fail. That's why you may hear "billet or nothing" when someone's picking out a roller cam. However, the aus-tempered process creates a very strong core to start with; it's not as strong as a billet roller, but it's a couple hundred bucks cheaper and will be more than strong enough for a build like this. Our new aus-tempered roller and a matching valvetrain is going to increase the 231's usable rpm limit from the low five grand range to over 6,000.
With these high-boost Buick engines, the factory hypereutectic pistons should always be replaced with a quality, forged set. For this build, we chose custom .005 over (3.805) JE Pistons. Hartline uses this size because most of the blocks that he runs across will clean up at .005--this minimizes how much boring you need to do to have fresh holes, and allows for more boring down the road. On top of that, "Even though I can't quantify this with a gauge, I have a feeling that the smaller the bore is, and the thicker the cylinder walls are, the cooler the engine runs overall."
Here's the underside of a Buick V-6 JE. The dish diameter of these custom pistons is slightly larger than the off-the-shelf 3.820/3.830 parts. That means they are lighter than the standard JEs: 470 grams per piston, as opposed to around 540 for the shelf JEs. "That is a big weight difference," JE's Tech Salesman Alan Stevenson states, "and this lighter piston will see substantially lower inertial forces, which will result in better connecting rod, crank, wrist pin, and rod bolt life expectancy. As far as the material, JE uses a 2618 aluminum alloy that is the industry standard, and this is the best performing alloy that is still affordable. What makes this piston among the best out there is that JE is able to manufacture pistons to keep the ring grooves flat. Simply put, the flatter the ring groove, the more horsepower you can make. Also, skirt shape is critical, and we think JEs are some of the most accurate." Additionally, the JEs have an oil passage that feeds oil scraped from the rings to the wrist pins.
Our custom pistons came with full floating pins, dual spiro locks per side (more difficult to install, but proven to provide the best wristpin retention at a reasonable cost), upgraded high-strength chrome bar stock wrist pins, rings, and the pin-fit option. Cal has assembled all of the rod/piston combos and laid out the 3.8's parts in preparation for assembly.
With the RJC main cap studs and bearings installed, Hartline begins by oiling up the bearings and placing the crankshaft in.
The thrust bearing is oiled up next and installed.
A rubber hammer is used to tap it in securely.
The RJC Racing girdle is test-fit at this point; the timing cover slides in from the front, and it doesn't allow you to get a good seal between the girdle and cover if the girdle goes on first.
In a big boost 10-second build, the 109 block will be stronger--and last longer--with some structural reinforcement. One of the great new products for TRs is RJC Racing's block girdle. It is made from .75-inch thick, 1018 billet steel and CNC machined for an exacting fit. RJC has customers who run reliable low 9s with a girdled stock block, so this should be more than adequate enough for this engine.
An initial check of the crank endplay is made--Cal is looking for about .006 clearance here. The rest of the caps are installed and torqued to 100 ft-lbs.
The JE rings were file-fit before the installation started. We're using 1/16 top, 1/16 second, and 3/16 oil JE rings, which are a good compromise between sealing and friction in this high-boost application.
The block is flipped over, and Cal installs the pistons and rods using a Tavia cone-shaped ring compressor.
Underneath, he lubes up the Clevite 77 bearings, places the rod cap onto the rod and tightens the high-quality stock bolts to 40 ft-lbs.
All six pistons and rods are installed.
As we were smoking cigars, taking notes, and generally acting like we were working, "LS1" Ashley grabbed the greasy pile that was our stock engine bolts, threw in some elbow grease, and shined 'em to their former glory. Thanks, Ash!
The roller cam is slipped into the block, then some modification of the stackup assembly was needed to get the cam endplay where Cal wanted it. Typically for a race motor, he sets the endplay around .001 to .007; for street motors it's usually .010 to .015. Hartline prefers not to use the stock-type spring-loaded cam button to set the endplay, and instead uses a solid stop that can be shimmed to the correct endplay. A Rollmaster double roller timing chain and its sprockets are installed.
The .036 multi-layer Cometic head gasket is placed.
And a Champion head is placed onto the block.
Hartline recommends using ARP head studs for this build, as they have a more even clamping force over head bolts. Cal applies thread sealer to each one, then they are tightened down with an Allen wrench until they bottom out.
He likes to torque the heads like so: 45, 55, 65, then 75 ft-lbs. Lastly, the long studs get a final torque to 80 ft-lbs.
With one head on, we'll degree the cam. Cal checks at .050-inch lift numbers based off of the cam card, then he double-checks using the intake centerline. He finds that our cam is only a little over one degree advanced; this is not a problem, as when the timing chain wears this should take care of itself.
With the other gasket and head installed, our Turbo 3.8 is well on its way. Check out our next installment, when we finish up the engine build.
LC2 Buttom End Engine Build - GM High-Tech Performance Magazine
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