Exhaust
Manifold Bolts by Ray Dyreson
Performance exhaust headers have always been notorious for
leaking at the gasket and the Fiero V6 is no exception.
My son’s 87 GT 3.4 with Sprint headers developed the dreaded
“tick-tick” noise on acceleration. We
tried tightening the header bolts, which is not easy due to the bends in the
header pipes. This helped for a
while, but the noise came back. Checking
the bolts showed they were loose again. I
learned from some local “muscle car” people that on their V8s they use
special bolts with lock tabs to stop the bolts from loosening for good. I called the manufacturer and found they make a kit for the
2.8 V6. The bolts are stainless
steel with both an Allen drive for quick turning down to seat in tight
clearances and a hex head for final torquing.
A teardrop shaped lock tab then slides over the hex head and is
positioned to jam up against the nearby header pipe.
This tab is held to the bolt by a C clip in a groove machined into the
bolt head. The bolt cannot loosen
as the tab totally prevents it. The
hardest part of the Fiero installation is getting the C clips into place with
little room for fingers. You might
want a few spare C clips. I have
not tried these on a stock manifold, but the bolts are 5mm shorter than the
standard bolt. This is desirable
for headers and may work on stock manifolds, but would give three less threads
to hold. The bolt kit is available
from Stage 8 Fasteners Inc., 64 Lois Street, San Rafael, CA 94901. The phone number is (415) 485-5340; the web site is www.stage8.com
Part number for the 2.8-34V6 is #6910 with a cost of $45/set of 12 bolts.
Ray Dyreson, Winnebago, IL. NIFE
member#132.
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