Plenum Studs

Recently I had to remove the air
cleaner plenum for the
first time. Unfortunately, when I tried
to spin the plastic thumbscrews
holding the plenum, they
simply spun and did not release the plenum.

Having
never removed the plenum before I didn’t know
how it was attached to the
radiator shroud below it. I
consulted the service manual and some pictures
in various
Corvette parts catalogs and realized that the plenum studs
were inserted into a key-hole in the radiator shroud and the studs were
held in the key-hole by a spring steel tang.

I inserted
a putty knife between the
radiator shroud and the plenum and was able
to hold the tang
in place while I removed the thumb screws.

Once
I had the plenum removed I looked to see if the plenum studs
were broken
but they appeared to be in good shape. It appeared
that the design was
simply a bad one and the spring steel tang
just didn’t exert enough downward
force the keep the plenum
studs from spinning.

I started
looking for a way to fix this problem and finally decided to drill a 1/8″
hole through the tang and the radiator shroud. I could then
pop-rivet
the tang to the shroud and the stud would then be
held firmly in place.

You
can see in the picture above the scratch mark left on the
radiator shroud
when the stud was spinning free. Notice that I
turned the tang 180� from
its normal position over the large
end of the key-hole in order to rivet
it to the radiator
shroud.

The
pop-rivet fix is
simple, looks like something the factory might have done
and
doesn’t interfere in any way with the existing components.

Note:
It appears that if you drill in
the area described above you will NOT
be drilling near the
radiator. But you should exercise caution when modifying
your
car as it may be different than mine.