In a recent issue of a Corvette magazine's Q&A section, a fellow that had just purchased a 1999 Corvette wrote in saying that a friend had told him that Corvettes used a combination of metric and standard fasteners. He wanted to know if this was true and whether he needed a metric tool set for his recent purchase.
The response said that since the introduction of the C4 in 1984 Corvettes had used metric fasteners exclusively. That's not exactly accurate. C4 Corvettes do not use metric fasteners exclusively. While it is true that most of the C4 Corvette, and all of the components newly designed and engineered for the C4 were metric, carry-over components continued to use SAE fastener sizes. This included the small block engine and most of the DN 4+3 transmission.
As the C4 period progressed certain elements of the small block engine were converted to metric. For the most part, this included peripheral items like center bolt valve cover hold-down, etc. However, the core engine utilized SAE fastener sizes right through the end of C4 production in 1996.
So, to work on a C4 in its entirety, one needs BOTH metric and SAE size tools. Of course, for C5 and C6, everything is metric and no SAE size tools are required.
Trivia question: is there any GM car in production today which uses both metric and SAE size fasteners? Well, for the 2008 model year the only ones I know of are the Pontiac Grand Prix and certain Buick models equipped with the 3.8L V-6 engine. That engine, with roots in the 60's, still uses SAE size fasteners for the core engine, but it will be going out-of-production VERY soon. And, then there'll be NONE.
There is one other engine which uses SAE fasteners that I almost forgot about. It's the 4.3L V-6, but it's used only for trucks at the current time. It's the derivative of the small block Chevrolet V-8 and shares its SAE fasteners even to this day. I believe it's scheduled to go out-of-production quite soon, too. This engine was mainly kept around because a V-8 wouldn't fit in an S-10 size pick-up truck. I don't know why anyone would want one of these engines, though. It's an engine with V-6 power but V-8 fuel economy. So, except for S-10, wouldn't you rather have a V-8?
The response said that since the introduction of the C4 in 1984 Corvettes had used metric fasteners exclusively. That's not exactly accurate. C4 Corvettes do not use metric fasteners exclusively. While it is true that most of the C4 Corvette, and all of the components newly designed and engineered for the C4 were metric, carry-over components continued to use SAE fastener sizes. This included the small block engine and most of the DN 4+3 transmission.
As the C4 period progressed certain elements of the small block engine were converted to metric. For the most part, this included peripheral items like center bolt valve cover hold-down, etc. However, the core engine utilized SAE fastener sizes right through the end of C4 production in 1996.
So, to work on a C4 in its entirety, one needs BOTH metric and SAE size tools. Of course, for C5 and C6, everything is metric and no SAE size tools are required.
Trivia question: is there any GM car in production today which uses both metric and SAE size fasteners? Well, for the 2008 model year the only ones I know of are the Pontiac Grand Prix and certain Buick models equipped with the 3.8L V-6 engine. That engine, with roots in the 60's, still uses SAE size fasteners for the core engine, but it will be going out-of-production VERY soon. And, then there'll be NONE.
There is one other engine which uses SAE fasteners that I almost forgot about. It's the 4.3L V-6, but it's used only for trucks at the current time. It's the derivative of the small block Chevrolet V-8 and shares its SAE fasteners even to this day. I believe it's scheduled to go out-of-production quite soon, too. This engine was mainly kept around because a V-8 wouldn't fit in an S-10 size pick-up truck. I don't know why anyone would want one of these engines, though. It's an engine with V-6 power but V-8 fuel economy. So, except for S-10, wouldn't you rather have a V-8?
Comment