EGR Hold-Down Studs-Length?
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Team Owner
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EGR Hold-Down Studs-Length?
If anyone has a stock L-82 intake manifold sitting in the garage, I would appreciate knowing the dimensions of the EGR studs, particularly the length. I believe the diameter is 1/4". Thanks.
Melting Slicks
Joined: Aug 2001
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From: Wichita KS
Re: EGR Hold-Down Studs-Length? (paul79)
Paul79,
I have a 1980 L-48, intake manifold 14014432. This aluminum manifold was used on the all the 1980 Corvettes (L-82, L48, and California 305). The EGR bolt hole depth, into the manifold, is about 0.7 inches. The threads are 5/16 inch, 18tpi.
I have a 1980 L-48, intake manifold 14014432. This aluminum manifold was used on the all the 1980 Corvettes (L-82, L48, and California 305). The EGR bolt hole depth, into the manifold, is about 0.7 inches. The threads are 5/16 inch, 18tpi.
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Team Owner
Joined: Aug 1999
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From: Ontario
Re: EGR Hold-Down Studs-Length? (mapman)
Thanks for the info! The EGR uses a gasket, a spacer, another gasket and then the EGR unit. I need to know the length of the stud in total. I am rejuvenating this #14007378 1979 L-82 intake and I am stuck. GM can't help. And of course the EGR is on the car in storage so I cannot take a physical measurement.
[Modified by paul79, 7:30 PM 11/28/2002]
[Modified by paul79, 7:30 PM 11/28/2002]
Melting Slicks
Joined: Aug 2001
Posts: 3,046
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From: Wichita KS
Re: EGR Hold-Down Studs-Length? (paul79)
paul79,
I looked some more. The EGR Unit including spacer - but EXCLUDING gaskets - is 0.6 inches thick. (That is, the portion of the EGR that the bolts attaching it to the intake manifold go through.)
The bolt length (shaft EXCLUDING the thickness of the bolt head) is almost 1.25 inches long. (5/16th, 18tpi).
With a guesstimate of the gasket thickness, it would seem those bolts would extend about 1/2 an inch into the manifold. You may want to adjust this length depending on washers/lock washers (if any), and the actual thickness of the gaskets you use. Again, this is on my stock 1980 manifold.
I looked some more. The EGR Unit including spacer - but EXCLUDING gaskets - is 0.6 inches thick. (That is, the portion of the EGR that the bolts attaching it to the intake manifold go through.)
The bolt length (shaft EXCLUDING the thickness of the bolt head) is almost 1.25 inches long. (5/16th, 18tpi).
With a guesstimate of the gasket thickness, it would seem those bolts would extend about 1/2 an inch into the manifold. You may want to adjust this length depending on washers/lock washers (if any), and the actual thickness of the gaskets you use. Again, this is on my stock 1980 manifold.
Thread Starter
Team Owner
Joined: Aug 1999
Posts: 30,995
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From: Ontario
Re: EGR Hold-Down Studs-Length? (mapman)
That is very interesting information...in more ways than one ;) . You seem to have bolts holding the EGR on; I have double-ended, threaded studs. The hold-down is by nuts. But the dimensions are very useful as the bolt head width is probably the same width as the nut. Thanks!
Melting Slicks
Joined: Aug 2001
Posts: 3,046
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From: Wichita KS
Re: EGR Hold-Down Studs-Length? (paul79)
paul79,
The bolts are what was on the car, but bubba was often working overtime so I have no idea what was original. In any case, especially for aluminum, I like the idea of a nut on a stud vs a bolt.
Looks like you did a great job cleaning up the EGR passage in that manifold. Mine was completely carboned up - looked like coal! I opted for a new GM Performance Parts intake, I'll save the original for another project.
The bolts are what was on the car, but bubba was often working overtime so I have no idea what was original. In any case, especially for aluminum, I like the idea of a nut on a stud vs a bolt.
Looks like you did a great job cleaning up the EGR passage in that manifold. Mine was completely carboned up - looked like coal! I opted for a new GM Performance Parts intake, I'll save the original for another project.
