Refinishing & Repairing - Ford Ranger Maintaince And Repair Manual

HOW TO USE THIS BOOK
Checks should also be made along both diagonals of the head surface
Place a straightedge across the gasket surface. Using feeler gauges, determine the clearance at the center of
the straightedge and across the cylinder head at several points. Check along the centerline and diagonally on
the head surface. If the warpage exceeds 0.003 in. (0.076mm) within a 6.0 in. (15.2cm) span, or 0.006 in.
(0.152mm) over the total length of the head, the cylinder head must be resurfaced. After resurfacing the heads
of a V−type engine, the intake manifold flange surface should be checked, and if necessary, milled
proportionally to allow for the change in its mounting position.
CRACKS AND PHYSICAL DAMAGE
Generally, cracks are limited to the combustion chamber, however, it is not uncommon for the head to crack
in a spark plug hole, port, outside of the head or in the valve spring/rocker arm area. The first area to inspect is
always the hottest: the exhaust seat/port area.
A visual inspection should be performed, but just because you don't see a crack does not mean it is not there.
Some more reliable methods for inspecting for cracks include Magnaflux®, a magnetic process or Zyglo®, a
dye penetrant. Magnaflux® is used only on ferrous metal (cast iron) heads. Zyglo® uses a spray on
fluorescent mixture along with a black light to reveal the cracks. It is strongly recommended to have your
cylinder head checked professionally for cracks, especially if the engine was known to have overheated and/or
leaked or consumed coolant. Contact a local shop for availability and pricing of these services.
Physical damage is usually very evident. For example, a broken mounting ear from dropping the head or a
bent or broken stud and/or bolt. All of these defects should be fixed or, if unrepairable, the head should be
replaced.
Camshaft and Followers
Inspect the camshaft(s) and followers as described earlier in this section.
REFINISHING & REPAIRING
Many of the procedures given for refinishing and repairing the cylinder head components must be performed
by a machine shop. Certain steps, if the inspected part is not worn, can be performed yourself inexpensively.
However, you spent a lot of time and effort so far, why risk trying to save a couple bucks if you might have to
do it all over again?
468 INSPECTION