4. Lift the manifold away from the cylinder head.
The air-cooled exhaust manifold (Fig. I) is mounted on
the cylinder head.
5. Remove the manifold gaskets.
A new exhaust manifold hold-down crab is now being
used. The new hold-down crab is made of a hardened
steel and is heavier than the former hold-down crab.
This will minimize wear and gouging of the manifold,
Remove the loose scale and carbon that may have
crab and cylinder head mating surfaces, which results in
accumulated on the internal walls of the exhaust
a loss in the torque on the hold-down crab nut. The
former and the new hold-down crabs are
interchangeable on an engine, however only the new
Examine the exhaust manifold studs for damage. If
crab will be serviced.
necessary, replace the studs. New studs are driven in to
25-40 Ib-ft (34-54 Nm) torque.
Also a new special washer is now used at the center
portions of the exhaust manifolds. This new washer will
Install Exhaust Manifold
more accurately control the seating area for the 7/16 "
nut or bolt. Only the new special washer will be
Install the exhaust manifold on the cylinder head as
1. Place new gaskets over the studs and up against the
Remove Exhaust Manifold
Remove the manifold as follows:
2. Position the exhaust manifold over the studs and
1. Disconnect the exhaust extension and muffler from
against the gaskets.
the exhaust manifold.
3. Install the bevel washers on the studs.
2. Remove the nuts and bevel washers that attach the
exhaust manifold to the cylinder head. It is suggested
that, as a safety measure, the nut be loosened but left
Install the bevel washers with the
on the center stud until all of the other nuts and washers
crowned sides toward the nuts.
have been removed.
3. Support the manifold and remove the nut and washer
from the center stud.
Fig. 1 - Typical Air-Cooled Exhaust Manifold Mounting.