GM Cadillac Engines

1995–1997 Project Engineer/ Quality Control Mgr ISO 9000, QS 9000/ R&D Development 

Originally hired as a Project Engineer for a pending GM contract by Engine Masters, a local automotive engine rebuilder for both case iron and aluminum engines sold to automotive garages around the Midwest. Mr. Stitt's initial duties centered around setting up a base line of the current manufacturing process and developing new machining cell process for conversion full CNC machining production and assembly plant using 6 sigma standards, per GM management at the time. 

After several GM walk through of the manufacturing plant, GM indicated to Mr. Ward, the current owner, that Engine Masters would have to pass a validation process in order to win the 10 year production contract.  Mr. Ward said "lets send them our normal production engine blocks and see how they do!" The 1st two engines lasted about 15 minutes on the dyno as I recall, not even close to 300 hours at full rated horse power and full rated RPM. So that was when Management became serious about Quality and Manufacturing Process.

The next 2.5 years that it took to build each test engine, ship to Roush Racing for Dyno testing, wait for the test results, inspect the return engine, develop new mfg techniques, build new test engines. The time line looked like this for the  48 engines tested. 

The first 2 ran about 15 min each. They failed so early because after the inspection to determine failure, the crankcase looked very very clean, like it never had any oil in it. This led me to believe that Roush had put the wrong intake injection system on. They had accidentally put the 4.5 injector system on the 4.1 engine which flood the pistons with too much fuel and wash the oil from the piston side walls.

The next big hurtle involved failure of the aluminum threads from cross threading or metal fatigue. This showed up in several places, esp. torque of the main crankshaft bolts and cylinder heads. The repair up to this point in time involved a heli-coil repair, but this contaminated the engine. I researched the issue and developed a time-sert, that was custom manufactured by a local screw machine vendor. Eventually, EM and GM both agreed that the product could not be done without this new manufacturing process for high torque locations.

The next big hurtle involved rebuilding 1000's of cylinder head to a new specification. Many of core engines had valve guides that were scored.  You can't just put a new valve in an old bore and expect it to work. It would quickly fail because the surface finish determines the oiling characteristics of the sliding parts. The Sunnen Equipment company made a special repair station that used air bearings to float the work table and when the valve guide was positioned manually into the correct location. The operator simply locked the head into place. Worked Great....but not designed for 1000's of valve guide repairs. 

Next I was given the original GM prints and using a CMM, I collected and processed a fairly large sample used heads to determine the exact valve bore location and sending the information to an excel spread sheet to determine the manufacturing characteristics. I determined thru sampling that the production heads must have been manufactured from at least 5 different vendors and most of the head would have failed the original bore specification after being used and run in a motor. The data sample confirmed range of manufacturing was between .015 to .022 out of tolerance based on the random sample taken.  The second major issue was that carbide tooling was necessary to handle the material hardness and because of the length of bore, the manufacturing carbide tooling was also brittle and could not be bent .015 without tool breakage.  In a special meeting held with the CNC tooling vendor, I discussed the possibility of using a new feature called probing. The original idea of the new feature was to measure critical product dimensions after manufacturing. This would keep product from being rejected because the head couldn't leave without being machined in tolerance correctly. Thinking outside the box... I convinced the equipment programmer to modify the program by adding a probing operation for each valve guide and calculate the theoretical center. This would completely eliminate tool carbide tool breakage. This remained a trade secret process that really worked and allow all the recycle head cores to be remanufactured at a rate similar to new production cast cores. 

Solving Engineering Problems has always been very exciting to me. So in this project, we used a combination of TQM and Six Sigma practices to ultimately win the GM contract. So a successful project is a combination of a team working towards a common goal. Using Six Sigma  or any TQM implementation a success has revealed 10 Critical Success Factors. They are, in order of importance:

1. Top management leadership & commitment
2. A well implemented customer management system
3. A continuous education & training system
4. A well-organized information & analysis system
5. A well-implemented process management system
6. A well-developed strategic planning system
7. A well-developed supplier management system
8. Equipping everyone in the organization, from top management to employees, with a working knowledge of the quality tools
9. A well-developed human resource management system
10. A well-developed competitive benchmarking system

Most of the quality initiatives can not answer this question, but Six Sigma can. Six Sigma is a process of asking questions that lead to tangible and quantifiable answers that ultimately produce profitable results. There are four groups of quality costs:

• External failure cost: warranty claims, service cost

• Internal failure cost: the costs of labor, material associated with scrapped parts and rework

• Cost of appraisal and inspection: these are materials for samples, test equipment, inspection labor cost, quality audits, etc..

• Cost related to improving poor quality: quality planning, process planning, process control, and training.

So the custom process that I developed specifically for the project was a combination of all the good ideas from a variety of sources. Production Cells using CNC, coordinate custom tooling with outside CNC equipment vendors, internal material handling and control processes of teardown, primary cleaning process of different materials, secondary cleaning, tracking of cross contamination of material, re-machining or reconditioning used parts to a new standard, develop new testing processes for sorting of rework, Setup and calibration of digital gages for SPC tracking of each manufacturing process, write CMM custom software for measuring critical components and build 48 custom prototype engines for thermal cycling, endurance accelerated life testing to failure mode thru Roush Racing. during the Validation Process running on dyno at full rated hp and full rated rpm for 300 hrs without a leak or needing any stripped thread repair. Each size engine needed to have an head replacement to simulate half life. Excel Worksheet I developed  for Tracking Validation Engines Measurements by Engine Size.

Mr. Stitt inherited being put in charge of the Quality Control Manager because managing his own company Quality and Manufacturing process for the previous two year shipments of OEM assemblies, the warranties averaged 0.001071 or 0.10 % on 150,000 units shipped. Prior to Mr. Stitt arrival, he was told that Engine Masters warranty returns were 100% and at that time it was about average for the remanufacturing industry at that time. 

Mr. Stitt has been working in the field of quality and manufacturing for nearly 24 years and have seen all the names come and go.  Total Quality Management cannot be represented by one or just a few concepts or methods.  TQM has always been the application and synthesis of many methods.  To understand TQM, one needs to understand the works of:  Joseph M. Juran, W. Edwards Deming, Armand V. Feigenbaum, Philip B. Crosby, Kauru Ishikawa, Genichi Taguchi, Walter A. Shewhart, Acheson Duncan, to name several.  There are many more. Several individuals have suggested that Six Sigma is TQM on steroids.  As in my definition, TQM is the development, deployment and maintenance of systems/processes related to quality producing business process excellence.

Several of the processes that I help develop, led to patents filed for by Michael S. Ward, owner of Engine Masters. 

Warranty Tabs

4.1

For 1987 a more powerful version of the 4.1 L engine was introduced in the Cadillac Allante, using a different camshaft profile and roller lifters to reduce friction, in addition to multiport fuel injection. This engine was rated at 170 hp (127 kW) at 4300 rpm and 235 lb·ft (319 N·m) of torque at 3200 rpm. The 4.1 was superseded by larger-displacement engines, and ceased production after the 1988 model year.

  4.5

An improved and enlarged version of the HT4100, the 4.5 L engine was never classified as HT4500.

Engineering allowed the company to begin increasing displacement and output again. A bored-out (to 92 mm (3.6 in)) 4.5 L (273 cu in) 4.5 version was introduced in 1988 with 155 hp (116 kW) and throttle body injection. Various versions of this engine were built from this introduction to the end of production in 1992 including a high-output LW2 version with multiport fuel injection which produced 200 hp (149 kW) and 270 lb·ft (366 N·m) for the Allante. Outside of the Allante, Cadillac introduced a port fuel injected 4.5 L V8 engine in 1990 with 180 hp (134 kW) and 245 lb·ft (332 N·m) across their car line up.

  4.9

A larger version of the 4.5, the L26 4.9, debuted in 1991 at 4.9 L with a square 92 mm (3.6 in) bore and stroke. Despite the fact that it had similar output to Allante's 4.5 L port fuel injected V8, the 4.9 L engine represented a significant upgrade for the remainder of the Cadillac lineup. Horsepower output was up 20 hp (15 kW) from the previous 1990 4.5 L engine and torque was up by 30 lb·ft (41 N·m), to 200 hp (149 kW) and 275 lb·ft (373 N·m). Both the 4.9 and 4.5 port fuel injected engines required premium fuel due to a 9.5:1 compression ratio. The 4.9 produces its maximum horsepower at 4100 rpm.

The 4.9 L was used throughout the Cadillac line. It was replaced by the newer 4.6 L Cadillac Northstar engine.