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| CYLINDER HEAD REPAIR AND REMANUFACTURING |
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| STEP 1) CYLINDER HEAD DISASSEMBLY |
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All cylinder heads are visually inspected for casting
defects prior to their disassembly. The parts are then
removed and individually inspected for damage and cause
of failure. The oil and water passage plugs are removed
to insure optimum results during the thermal cleaning
process.
Only premium castings are used for our marine cylinder
heads, all castings are replaced for all the salt-water
applications. Our high performance cylinder heads are
built with premium cores. In many applications new castings
are used, as we never employ repaired castings. To retain
your classic cars's original cylinder head casting,
Promar employs the best skilled casting repair technicians
in the industry.
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Dirty Cylinder Head |
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| STEP 2) CYLINDER HEAD THERMAL CLEANING |
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The thermal cleaning system gives our customers the
closest thing to a new casting, taking engine parts to
a whole new level of clean. The heaters emit uniformly
controlled heat, which is evenly distributed throughout
the chamber. This method totally eliminates the concentration
of intense heat or flame entering the chamber, which could
overheat, warp or melt parts. The load is heated to 650-800
F (340-427C) in an oxygen deficient atmosphere, where
the combustible hydrocarbons decompose and parts leave
the oven completely dry. This baking process used on cast
iron cylinder heads only employs the Ace RKE 230 oven.
Ash residue is easily removed by stainless steel shot
blasting which is the next step in the cylinder head repair process.
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Oven-Cleaned Cylinder Head |
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| STEP 3) CYLINDER HEAD SHOT BLASTING |
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Our shot-blasting machine employs a cleaning method
using stainless steel shot. This finishing process is
used by Promar to remove surface contamination such
as rust and irregularities from cylinder heads during remanufacturing. The
result of this method is a cleaner smoother surface
finish to make easy the detection of surface and subsurface
casting defects during quality inspection.
To insure stress free casting, the peening process
is used to impart compression strength to metal parts.
This is accomplished by metal shot pellets acting like
miniature ball peen hammers as they strike the entire
surface of the cylinder head. All iron castings are
put through this process before a preliminary inspection
for defects is done. This process using the AR-HB41
is employed for cast iron cylinder heads only and facilitates
a more accurate magnetic particle inspection.
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Shot-Blasted Cylinder Head |
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| STEP 4) CYLINDER HEAD MAGNAFLUXING |
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Magnetic Particle Inspection Process |
Magnetic particle inspection is the most definitive method of detecting cracks
and imperfections in any ferrous engine parts. This procedure assures the
highest quality cast iron cylinder heads. The next process of cylinder head repair is pressure
testing, but first, let us explain how aluminum cylinder heads are cleaned,
pressure tested and checked for casting defects.
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| STEP 5) CYLINDER HEAD HIGH PRESSURE WASH |
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AXE SW-20 OS Spray Cleaning Machine |
The first stop for a qualified aluminum cylinder head during remanufacturing is our AXE SW20
OS spray cleaning system. With twice the spraying power and a dramatically
increased number of multi integrated spray nozzles, this state of the art
system assures Promar that all oil, dirt and foreign material is removed
from even the smallest of oiling holes. Cleanliness of the aluminum cylinder
head is essential to insure an accurate inspection. This process is used
on all aluminum cylinder heads as a first step prior to the second step
of ultrasonic cleaning.
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| STEP 6) CYLINDER HEAD SONIC CLEANING |
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GMC-1818B Ultra Sonic Cleaner |
Promar's second process in the cleaning of aluminum cylinder heads
during repair is the ultrasonic cleaning method, long known as the "benchmark"
in cleaning. Hundreds of specifications reference an ultrasonically
cleaned part as the ultimate target for cleanliness. Ultrasonic
cavitation is able to clean right down to the surface of a part and
beyond. It is also able to reach internal areas, which are not accessible
by using other cleaning means including spray and mechanical agitation.
The forceful nature of ultrasonic energy provides the physical "push"
required to break the mechanical and ionic bonds that hold very small
particles to surfaces. Once cleaned the cylinder head is sent for pressure
testing.
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| STEP 7) CYLINDER HEAD PRESSURE TESTING |
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Delta 6000 Pressure Tester |
Promar uses the Delta Pressure tester to double check for pin holes
after magnafluxing and dye testing are completed. Cracks and defects
not detected during the first cylinder head remanufacturing process are found at this time. This
second process insures the integrity of all castings used in Promar
products.
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Pressure Testing Process |
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| STEP 8) CYLINDER HEAD PREPARATION |
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Broken Bolt Removal Process |
During the head preparation and after pressure testing, minor cylinder head repairs
are carried out. Broken bolts are removed and repair and tapping
of threads completed. Gasket surface repairs are accomplished in order
to minimize stock removal. All guides are inspected for replacement or
fitted with new oversized valves. The heads are now ready for line honing.
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| STEP 9) CYLINDER HEAD LINE HONE |
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Line honing is the best method for precision alignment of overhead
camshaft cylinder head bores. Promar uses the Sunnen CH-100
machine for all of its benefits and features, as we can minimize stock
removal, usually less than .003" (.076 mm) off the caps compared to as
much as .010" (.254 mm) with boring. Use of this machine maximizes
precision and corrects distortion caused by warpage and cap stretch.
This line hone procedure during cylinder head remanufacturing exceeds original factory accuracy for
alignment, roundness and size.
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Sunnen CH-100 Line Hone Machine |
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| STEP10) CYLINDER HEAD MACHINING |
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In cylinder head machinging, classic car heads previously designed to use leaded gas
must be updated with seats and valves compatible for use
with unleaded gas. Marine and high performance heads are
fitted with new guides before valve seat resurfacing.
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| STEP 11) CYLINDER HEAD SEAT REFACING |
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Promar's head machining center has a rigid head
and base enabling delivery of high precision multiple
angle seat to guide concentricity within .001 or less
per 1" of valve diameter. The variable speed cutter
head on the DMC series 2000 assures chatter free seat
finish. All seats are checked with a vacuum tester while
still on the machine. A second check is done after final
assembly to insure optimum valve and seat seal. The next
process during cylinder head repair is milling of the heads.
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HCM-2000 |
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Valve Seat Resurfacing |
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| STEP 12) CYLINDER HEAD MILLING |
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Milling machines that are used by Promar are set up
specifically for heads. The Winona Van Norman M3000 machines
are used for their variable feed rate, which is essential
to acquire proper Ra finish for each head. Ra finish determination
is based on the type of head, be it aluminum or cast iron
and by the type of gasket used for each specific application.
These machines utilize CBN (cubic boron nitride) cutters,
which are second in hardness only to a diamond, to maximize quality work during cylinder head remanufacturing. During
the cutting process heat from friction is absorbed and
carried off by the discarded metal chips thus resulting
in improved accuracy and excellent surface finish. Promar
insures proper measurement of Ra by utilizing the Mitutoyo
SJ-301 twice, once after resurfacing and again before
final assembly.
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M-3000 |
Surface Ra Testing |
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| STEP 13) CYLINDER HEAD FINAL WASH |
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All heads are then washed with a mild detergent and
rinsed before the final assembly.
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Cylinder Head Washing Process |
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| STEP 14) CYLINDER HEAD ASSEMBLY |
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At the time of assembly, Promar installs new oil and
water plugs in all its cylinder heads, using brass plugs
in our marine applications. The springs are checked
for proper pressure as well as the installed heights
checked and new Viton seals installed. All our overhead
cam heads include new cams, rockers, lifters and cam
seals.
The final assembly process is accomplished using the
CHW-50 Cylinder Head Workstation. This machine takes
the work out of head assembly and disassembly. It makes
precision automotive head rebuilding easier than ever.
The entire valve train, including cams, rocker arms,
cam buckets, springs, valves, etc. can be easily removed,
reinstalled and adjusted while the head is mounted in
the workstation. Once final assembly is completed the
heads are vacuum tested and then wrapped.
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CHW-50 Cylinder Head Workstation |
Head Spring |
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