In order to increase the horsepower and displacement of his Corvette ZR-1, Phil Wasinger started his engine manufacturing when he found a used LT5 engine on Craigslist in 2014. Take a look at what happened to this six-year project.
Due to the unique design and limited production of the 1990-1995 ZR-1 Corvettes, the naturally aspirated LT5 engine did not enjoy the performance aftermarket like Chevrolet, Chrysler and Ford’s other mass-produced engines. However, this did not stop it. Phil Wasinger rebuilt his LT5 engine in his 1994 ZR-1 Corvette.
The main purpose of the LT5 engine was that when Lotus Engineering (owned by GM at the time) designed the LT5, GM insisted that they use the same cylinder hole spacing, cylinder block deck height, and crankshaft main bearing hole diameter as SB Chevy, although otherwise, it It is a completely different engine design, except for the crankshaft rear oil seal, there are no common parts between them. When leaving the factory, the LT5 cylinder block adopts an open deck design, and the lower cylinder block is drilled to accommodate the 4.173˝ OD step aluminum lining.
Wasinger’s engine rebuild began in 2014, when he found a used LT5 engine on Craigslist.
“I purchased my 1994 Corvette ZR-1 in 2007 and upgraded the engine with the usual bolt-on modifications suitable for these unique engines,” Wasinger said. “This includes long pipe headers, performance catback exhaust, port intake, and performance tuning chips. For the 350 cid, most stock engines run well, output about 485 horsepower, and easily turn to 7,200 rpm. However, I really want to See what the DOHC LT5 engine design can do by adding displacement, cylinder heads, and custom performance cams. This started my 6-year epic journey of the 427 cid LT5.”
In terms of engine manufacturing, Phil is no ordinary DIYer. For most of his career, he has worked for the large German diesel engine manufacturers MTU Friedrichshafen and MAN Augsburg, leading their operations in the United States. The U.S. Navy, the U.S. Coast Guard and the American Flag Commercial Shipping Company are his main customers.
However, unlike the work he has done in his career, this LT5 construction is a personal hobby project, mainly done in Phil’s family garage. The machine work and balance were done in his local engine machining workshop near his hometown in Fairfax, Virginia, in northern Virginia. First of all, Phil knew he wanted more horsepower and more displacement.
“Our goal is to provide a smooth and reliable 650 horsepower for the street and cruising,” Vasinger said. “Due to the unique design of the LT5, the stroke crankshaft must be machined from the blank. The crankshaft has a large number of internal boreholes as the only oil distribution channel for the main bearing and connecting rod bearing. Fortunately, I was from a person in Texas The gentleman obtained an unused steel billet 4.00˝ crankshaft. He originally bought it for the LT5 version, but failed to realize it.
“In order to use the 4.000˝ stroke crankshaft to reach the target of 427 cid, the cylinder bore must be increased from 3.900˝ to 4.125˝, which requires the expansion of the cylinder receiver bore. For this, I turned to Pete Polatsidis, an LT5 engine expert in Chicago , He developed a closed deck ductile iron bushing conversion and Darton Sleeves for the LT5 engine.”
The LT5 cylinder block is designed to use 99mm aluminum bushings and pistons produced by MAHLE. The inner surface of the lining is coated with Nikasil to provide a very durable wear-resistant surface. The configuration is an open deck design with the lower part of the liner slidingly fitted into the receiver hole machined to the bottom of the block.
In order to achieve the 4.125˝ hole that Phil wanted, it was necessary to use a specially modified ductile iron lining originally produced by Darton Sleeves and improved by Pete Polatsidis to use a closed deck design.
“With this closed deck liner, the cylinder inner diameter can be safely increased to 4.125˝, and the other advantage is that it is more stable in the cylinder,” he said.
After understanding the crankshaft and engine displacement, Phil turned his attention to other internal components, such as 6-inch billet connecting rods each weighing 605 grams, paired with custom Diamond forged aluminum pistons with skirt coatings and offset pins.
“The piston has a compression ratio of 12:1, and the offset pin and skirt coating are specifically designed to reduce cold-start piston noise,” Wasinger said. “I also used Total Seal piston rings-a 1.5mm malleable molybdenum top ring, a 1.5mm malleable cone twisted second ring, and a 3mm oil control ring.”
The LT5 version also received Calico coated bearings-OEM on the main power supply and 2.1˝ coated Clevite 77 bearings on the rod. The journal clearance between the rod bearing and the main bearing is installed at 0.0025˝.
When it comes to cylinder heads and valve trains, Phil pointed out that the LT5 four-valve cylinder head combustion chamber is designed to be very anti-knock, allowing higher compression ratios to be used when pumping air. In order to maximize his setup, the cylinder head was completely transplanted and flow tested. The air inlet is opened up to 37 mm, and the air inlet bowl is also enlarged.
“The original 39mm intake valve was replaced by Ferrea’s 42mm stainless steel valve with an 8mm stem,” he said. “The intake valve seat was also enlarged to take full advantage of the larger intake valve. I also used Ferrea springs and retainers.”
In order to make the valve mechanism work properly, Wasinger chose a custom billet camshaft from Jones Cam Design. In addition to his own work, Phil said that rotating component balancing and custom cylinder head valve work was done locally by Lloyd Lovelace of Custom Automotive Machine in Lorton, Virginia. The final of the automobile dynamometer tuning was conducted by Haibeck Automotive Technology in Addison, Illinois.
After the LT5 was fully assembled and adjusted, Wasinger said he got the 650 horsepower he hoped. Now, this 1994 ZR-1 Corvette is back on the street.
This week the engine was sponsored by PennGrade Motor Oil, Elring – Das Original and Scat Crankshafts. If you have an engine you want to highlight in this series, please send an email to [email protected] Engine Builder editor Greg Jones
Post time: Sep-13-2021
