When did Chevy start center bolt valve covers?
Chevrolet, a division of General Motors, began using center bolt valve covers on some of its engines in the late 1950s. This design change was introduced to improve the sealing and durability of the valve cover assembly.
The Transition to Center Bolt Valve Covers
Prior to the late 1950s, Chevrolet engines typically used valve covers that were secured with bolts around the perimeter of the cover. This design was prone to leaks and required more maintenance over time as the gasket material degraded. 1 To address these issues, Chevrolet engineers developed a new valve cover design that used a single bolt in the center of the cover to provide a more consistent and reliable seal. 2
The center bolt valve cover design was first introduced on Chevrolet's small-block V8 engines in the late 1950s, starting with the 283 cubic inch (4.6 liter) engine. 3 This design quickly became the standard for Chevrolet's V8 engines and was later adopted for other engine families as well, including the big-block V8s.
Benefits of the Center Bolt Valve Cover
- Improved sealing: The single center bolt design provided a more even distribution of clamping force, resulting in a tighter seal and reduced oil leaks.
- Easier maintenance: The center bolt design made it easier to remove and replace the valve cover, simplifying routine maintenance tasks like checking and replacing the valve cover gasket.
- Enhanced durability: The center bolt design was more resistant to warping and distortion over time, helping to maintain the integrity of the seal.
The center bolt valve cover design became a hallmark of Chevrolet engines and remained in use for decades, contributing to the reliability and ease of maintenance that Chevrolet customers have come to expect.
What is torque in bolt tightening?
It is a measure of how much force acting on an object which causes that object to rotate. What is Torque Tightening? The application of preload to a fastener by the turning of the fastener's nut. Friction points should always be lubricated when using the torque tightening method.
Does the 5.3 have aluminum heads?
Among the advantages of these engines are factory aluminum heads, lightweight composite intakes and in some cases aluminum blocks. Many, such as the 5.3L (RPO LM7) have a cast-iron block with aluminum heads and composite intake.
Do valve cover bolts need to be torqued?
Depends on the valve cover. If it's an old type pressed steel one that sits on a 1/4″ thick cork gasket then no. If it's a cast aluminium one that mates to a cast aluminium cylinder head with either a thin gasket or no gasket and just a thin smear of sealant, then yes.
When did Chevy start using aluminum heads?
Kicking off the '90s with a bang was the aluminum head LT5 that was exclusively found in the original '90-'95 ZR-1 Corvette. It was produced in partnership with Lotus and Mercury Marine, and was purely designed with performance in mind.
When did Chevy start making the bolt?
2017
Sales of the 2017 Bolt began in California in December 2016; it was released nationwide and international markets release in 2017. A rebadged European variant was marketed as the Opel Ampera-e in mainland Europe. In 2017, the Bolt was the second-best-selling plug-in car in the United States.
When did Chevrolet start using center bolt valve covers?
In 1987, another round of changes were made, this time to the top of the engine. Engine now has Center Bolt valve covers (Figure D), and the intake manifold bolt angle has changed on the four center intake bolts, thus making all previous intakes not applicable to the 1987-1997 Engines.
Are all center bolt heads Vortec?
Yes, GM made non-vortec center bolt valve cover heads, if that's what you mean. IIRC, Vortecs have a "sawtooth" stamping on the front of at least one head. Best to check the casting numbers and ask someone on here what you have.
What is the torque on center Bolt valve covers?
Torque the valve cover bolts to 5-6 ft/lbs, making sure gaskets do not slip out of position. Proper torqueing will help to ensure that your covers do not leak oil.
What year did Chevy start using metric bolts?
When General Motors decided to go metric in 1973, letters announcing the move were sent to its 47,000 suppliers. Six months later the manufacturer held a meeting for 600 of its suppliers of nuts and bolts to explain the thread system it had adopted. The mostly metric Chevette was the result.
When did Chevy start using roller lifters?
GM first began installing roller cams in some Chevrolet small-block, V8-equipped cars in 1987. But OE roller-cam installations in trucks didn't occur until 1995.
