The DOHC's front steel lifting strap is often used as a dogbone mount.
In my case, it broke the three-hole half-circular Power Steering pump
mounting area. In order to make a stronger dogbone, but keep
the ideal location
I had to figure out how to get a few bolts into the head, like the
standard
Lumina DOHC dogbone mount does. This picture shows the new dogbone
mount
in place with the standard engine lifting strap bolt already in.
But... you
get the two other bolt holes shown--which go into the head--adding
considerable
strength.
So: where do these bolt holes into the head come from? they come
from the timing belt
tensioner bracket, which is using those two holes. I got the dogbone
to share these holes
with the bracket by millingoff a 3/16" flat surface on the back of
the bracket, so the 3/16" thick
dogbone can fit behind this aluminum bracket, and both can use the
same bolts. The surface must
be exact, and should only be done using a mill.
Not pictured is a small amount of grinding I had to do the the back
of the timing chain cover to clear
thisomewhat thick dogbone bracket. The steel lifting strap would just
snake down into that crevice,
but I had to grind out a bit on back of the cover to make a thicker
piece of steel sneak down in there.
So: here is the mount installed. the dogbone using the three lower bolts
in the head
plus the upper one on the cam carrier for stiffness. I avoided using
ANY holes
on the power steering pump mount since it's flimsy. If the dogbone
breaks, the worst that
can happen is it breaks the hole tapped into the cam carrier, which
is not that big a deal,
when thinking of possible disasters. I suppose that one could worry
about it breaking down low
and affecting valve timing, but other dogbone mounts integrate to motors
in such a way that they
can cause similar disasters.
I also wanted to use the standard Iron Lumina dogbone mount next to
cylinder 6.
This intuitively wants to be very close to the Fiero firewall. Seems
great until you
notice the firewall is about 16 guage steel thick, and that's IT!!.
I made this engine
mount similar to what you can buy in any store, but with a properly
sized donut in it.
Just sooooo happens, a cut apart Ultimate Dogbone from the Fiero Store
is the
perfect fit. I cut the round portion off and welded it to a 1" tall
mounting surface.
And lastly. That thin steel wall? Strengthened it with 1/8" thick plate
spot-welded to help
prevent brittle breakage of the sheet metal. A bonus pic of my DOHC
ECM sitting
(well.... hanging out) in the standard Fiero ECM place. It sits on
a piece of foam and
though it's not bolted in per se, it's snug and safe when the center
console peice is
put over it.