fulvani lisanne obelya

[Kiliano Ratha]

In Part 1 of our 540 cubic inch big block Chevy build, we covered prep of the Dart Big M block, balancing and installation of the Scat/ICON reciprocating assembly, and installing the COMP Cams solid roller camshaft and timing gear. All good stuff.

In Part 2, we continue the build with the oiling system; installing the Dart Pro 1 cylinder heads and Harland Sharp roller rocker arms; and a Dart rocker stud girdle. We also checked piston to valve clearance and measured for proper pushrod length.

We chose a Melling high volume/high pressure oil pump for this build. The pump body is CNC machined from 6061-T6 billet aluminum and has an integral pickup screen to keep the pickup from loosening. Features include smoother oil flow and less internal drag as compared to conventional pumps; billet spur gears; a chromoly driveshaft with extended support; an adjustable pickup screen; and multiple pressure settings. Another very nice feature are machined stand-offs at the bottom of the pump body surrounding the screen area. They prevent smothering the screen in case the pan sump ever touches the pump.

The Melling oil pump requires an oil pan with an eight inch deep sump. The pump includes a mounting stud and nut, but I opted to use an ARP pump stud as it features a female hex that is handy for installation or removal.

Suitable for street, drag or road race use, the Moroso steel oil pan has the required eight inch deep kickout sump and a sump capacity of 6.5 quarts. The pan can handle Stroker cranks up to a 4.250 inch stroke. Features include a trap door baffle system, windage tray and crank scraper; and a 1/4 inch NPT dipstick bung located on the right side of the pan.

During test fitting, I checked for oil pump to pan sump floor clearance, Block pan rail to pump bottom measured 7.750 inches. Adding in a 0.100 inch crushed oil pan gasket, total pump to sump clearance was 0.350 inch.

The only glitch I ran into involved a clearance issue between the oil pump and a baffle in the lower rear wall area of the pan sump. The pump contacted the baffle, preventing the pan from moving rearward for proper bolt hole alignment. I trimmed the steel baffle to eliminate the contact. In fairness, Moroso designed the pan for a stock-style pump, which would have cleared just fine.

I secured the pan to the block using ARP stainless steel studs. I installed the studs into the block rails hand-tight with Loctite 242 medium strength thread locker. The nuts were torqued to 12 ft.-lbs.

Our solid roller lifters are Morel Black Mambas. They have a 0.842 inch OD billet steel body and are 0.300 inch taller than the stock Gen. VI big block lifters. This is required to accommodate the taller lifter bores in the Dart block. Summit Racing carries Howards Cams RaceMax solid roller lifters that are a great alternative to the Morels.

The heads were sealed to the block with Cometic MLS head gaskets and ARP head studs. The gaskets have an embossed design that promotes an even clamp load across the sealing surface to reduce bore distortion. The outer layers are coated with Viton fluoroelastomer rubber that is exceptionally heat-resistant.

The ARP head studs are designed specifically for the Pro 1 cylinder heads. This set features 12-point nuts that were torqued to 70 ft.-lbs. in three stages (30 ft.-lbs., 50 ft.-lbs., and 70 ft.-lbs.).

Piston to valve clearances were checked with a dial indicator and double checked with clay. With our COMP Cams solid roller cam set straight up and a cylinder head installed with no gasket, piston to valve clearance was approximately 0.100 inch at the intake valve and 0.030 inch at the exhaust valve. Adding the 0.040 inch thick Cometic gasket increased intake clearance to 0.140 inch and exhaust to 0.070 inch.

Factory big block Chevy intake pushrod length is 8.275 inches and exhaust length is 9.250 inches. Dart notes that the intake pushrod should be around 0.200 inch longer and exhaust another 0.250 inch longer, but that you must measure to make sure due to variables like deck height, head gasket thickness, and cam specs.

We started on the exhaust side with a pushrod length checker set at 9.450 inches. That made a witness mark pretty close to center on the valve tip, but just a tad toward the outside (exhaust side). Adjusting the checker to 9.400 inches provided a very satisfactory center witness mark sweep of about 0.050 inch wide on the exhaust valve tip.

The pushrods I chose were Elgin Pro Stocks. Made from 4130 chromoly steel, the one-piece pushrods are 3/8 inch in diameter with a 0.137 inch thick wall. They also have 5/16 inch, 120 degree ball ends to accommodate high lift cams. Summit Racing carries COMP Cams Hi-Tech 210 pushrods that have very similar specifications except for slightly thinner 0.035 inch thick walls.

Using a brass drift and a hammer to gently strike the fulcrum point of the guide plates, you can move and fine-tune the rocker arm rollers to properly center on the valve tips. Remove the rockers, torque the rocker studs to the final value of 55 ft.-lbs., and reinstall the rockers to verify alignment. If the rockers have moved, repeat the process.

This paper reports a novel room-temperature hermetic liquid sealing process where the access ports of liquid-filled cavities are sealed with wire-bonded stud bumps. This process enables liquids to be integrated at the fabrication stage. Evaluation cavities were manufactured and used to investigate the mechanical and hermetic properties of the seals. Measurements on the successfully sealed structures show a helium leak rate of better than 10 (10) mbarL s (1), in addition to a zero liquid loss over two months during storage near boiling temperature. The bond strength of the plugs was similar to standard wire bonds on flat surfaces.

The first part of the thesis deals with the integration of bulk wire materials. A novel approach for the integration of at least partly ferromagnetic bulk wire materials has been implemented for the fabrication of high aspect ratio through silicon vias. Standard wire bonding technology, a very mature back-end technology, has been adapted for yet another through silicon via fabrication method and applications including liquid and vacuum packaging as well as microactuators based on shape memory alloy wires. As this thesis reveals, wire bonding, as a versatile and highly efficient technology, can be utilized for applications far beyond traditional interconnections in electronics packaging.

The second part presents two approaches for the 3D heterogeneous integration based on layer transfer. Highly efficient monocrystalline silicon/ germanium is integrated on wafer-level for the fabrication of uncooled thermal image sensors and monolayer-graphene is integrated on chip-level for the use in diaphragm-based pressure sensors.

The last part introduces a novel additive fabrication method for layer-bylayer printing of 3D silicon micro- and nano-structures. This method combines existing technologies, including focused ion beam implantation and chemical vapor deposition of silicon, in order to establish a high-resolution fabrication process that is related to popular 3D printing techniques.

This thesis treats the development of packaging and integration methods for the cost-efficient encapsulation and packaging of microelectromechanical (MEMS) devices. The packaging of MEMS devices is often more costly than the device itself, partly because the packaging can be crucial for the performance of the device. For devices which contain liquids or needs to be enclosed in a vacuum, the packaging can account for up to 80% of the total cost of the device.

The first part of this thesis presents the integration scheme for an optical dye thin film NO2-gas sensor, designed using cost-efficient implementations of wafer-scale methods. This work includes design and fabrication of photonic subcomponents in addition to the main effort of integration and packaging of the dye-film. A specific proof of concept target was for NO2 monitoring in a car tunnel.

The second part of this thesis deals with the wafer-scale packaging methods developed for the sensing device. The developed packaging method, based on low-temperature plastic deformation of gold sealing structures, is further demonstrated as a generic method for other hermetic liquid and vacuum packaging applications. In the developed packaging methods, the mechanically squeezed gold sealing material is both electroplated microstruc- tures and wire bonded stud bumps. The electroplated rings act like a more hermetic version of rubber sealing rings while compressed in conjunction with a cavity forming wafer bonding process. The stud bump sealing processes is on the other hand applied on completed cavities with narrow access ports, to seal either a vacuum or liquid inside the cavities at room temperature. Additionally, the resulting hermeticity of primarily the vacuum sealing methods is thoroughly investigated.

Two of the sealing methods presented require permanent mechanical fixation in order to complete the packaging process. Two solutions to this problem are presented in this thesis. First, a more traditional wafer bonding method using tin-soldering is demonstrated. Second, a novel full-wafer epoxy underfill-process using a microfluidic distribution network is demonstrated using a room temperature process.

After a couple unfavorable attempts to get the Civic down the track for a full-power pass, we got the Civic back in our shop to conduct an inspection. Based on the datalogs from the MoTeC engine management system, the head gasket seal had been compromised. Thus, we pulled the engine for a complete teardown and analysis before any catastrophic damage occurred.

While the pistons showed no signs of encountering detonation, the extreme cylinder pressures that result when 620 lb-ft of torque is generated by a 2.0-liter engine at 45psi of boost pressure appear to be more than the off-the-shelf 8740-alloy ARP head studs (208-4303 for GSR or 208-4601 for B16) could handle. When torqued to 80 lb-ft (about 10 lb-ft above the recommended spec), the 8740-alloy studs provide enough clamping force to keep the head in place at 500 lb-ft of torque. However, these studs fell just a bit short of providing enough clamping force to eliminate head lifting when torque eclipses the 600 lb-ft mark. Fortunately, ARP offers a higher strength Custom Age 625+ alloy for those building engines that develop extremely high cylinder pressures. Considering that we are producing nearly six times the factory torque output of the engine, you can be sure that our cylinder pressures are definitely in the extreme range.

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