Converting Lifters from flat to roller The return of performance

Document Sample
Converting Lifters from flat to roller The return of performance Powered By Docstoc
					                      Converting Lifters from flat to roller

                                                    Pistons are Bill Miller Engineering forged,
                                                    9.5:1 flat-tops with floating pins.
The return of performance to production             Reciprocating parts were balanced by
Chevrolet in the late-80s and early-90s             Evans Speed Equipment in South El
was driven by two key events: continued             Monte, California.
development of computer controls and
roller hydraulic lifter camshafts.
                                                    The cylinder heads are cast iron, L82
                                                    Corvette units modified by Mark
Roller lifters or “Rollerized valve tappets”        DeGroff’s Cylinder Head Service. The
first saw widespread use in World War II            original camshaft was a flat-tappet
military aircraft engines. In the late-             hydraulic working rapid bleed-down lifters
1950s, hot rodders discovered the idea              and production Chevrolet valve gear.
and, within ten years, roller lifter                Exhaust is a set of Hooker Super
camshafts or just “rollers” were an                 Competition adjustable race headers
accepted ticket to maximum horsepower               fitted with Flowmaster collectors and
from engines with pushrod-operated                  blowing through three-inch pipes and
valves.                                             Flowmaster mufflers. The induction is a
                                                    rare, Rochester, mechanical port fuel
In the early-’80s, enamored with the roller         injection system from a 1964 Corvette.
lifter’s reduced friction and ability to work
with higher valve lifts for a given duration,       Tear Down
General Motors developed them for
production applications. Eleven years
ago, Chevrolet introduced hydraulic roller          We did this job like most readers would
lifters in the small-block V8s used in              do it: in a small garage with the engine in
Corvettes and Camaros.                              the car. The first step was to tear the
                                                    motor down enough that we could get the
                                                    camshaft out. In many “flat-to-roll”
Aftermarket camshaft manufacturers                  conversions, this means pulling the
soon hopped on the bandwagon with                   heads because the valve spring seats will
roller hydraulic lifters for engines not            probably have to be enlarged.
originally equipped with them. Since then,
a popular upgrade is switching from a
flat-tappet hydraulic cam to a roller               Space is limited, here, so we’re skipping
hydraulic. We decided that an interesting           disassembly basics. If you need help with
exercise would be to do this swap, but              that, consult a service manual. Year One,
make the cam change the only                        Inc. sells Chevrolet Chassis Service
modification affecting performance.                 Manuals for ’65-’72 Chevelles and other,
                                                    older platforms. Helm, Inc. has factory
                                                    manuals for newer models. In some
Our test case was a ’65 Chevy Malibu                cases, less expensive, non-factory
powered by a 400 cubic-inch, small-block            manuals for ’68-up cars are available
V8. It has a two-bolt-main block bored              from Haynes Publications. If you want a
.020-in. over and a production crankshaft           book that covers just engine assembly
that was Magnafluxed and deburred.                  and disassembly, Motorbooks
Stock rods were Mag’ed, deburred, had               International has several choices. Lastly,
their beams polished and were fitted with           consider David Vizard’s book How to
B&B Performance rod bolts (p/n 38630).              Build Chevrolet Small-Block Camshafts

                       Converting Lifters from flat to roller

and Valve Trains, published by                       very bottom of the release, then simply
Motorbooks. It’s the best work on the                pull the lever back and the cam will come
subject in the last 15 years and a must-             out.
read resource for anyone wanting to
understand the high-performance, SB                  The step was to clean parts and repaint.
Chevy valve train.                                   We used Eastwood Chassis Black (p/n
                                                     1244Z) for accessory brackets and
How about some Chevelle-specific tricks              Eastwood Chevrolet Orange (1232Z) for
not in books? First, you can’t remove the            the harmonic damper, valve covers,
oil pan with the engine in the car because           water pump and timing chain cover.
the front crossmember is in the way.
However, except for that rare engine                 Cam Installation
equipped with a two-piece timing chain
cover, you must drop the pan to remove               Crane Cams is an innovator in roller lifter
the cover and gain access to the cam.                camshaft technology. It was first in the
The solution?                                        aftermarket with roller hydraulic cams.
                                                     Though Crane did not originate the idea,
Once the engine is stripped down, raise it           in conjunction with its subsidiary and
as high as it will go then support it with           OE GM supplier, Camshaft Machine; it
wood blocks (4”x2.5”x1.5”) placed                    developed high-volume production of
between the motor mounts and the motor               steel billet, roller cams with interference-
mount brackets on the frame. Be careful              fit, cast iron distributor gears. This
to keep you fingers out of the space                 advancement allowed roller hydraulic
between the mounts and frame while                   cams to meet OE durability goals paving
placing the blocks. If the jack fails, your          the way for their use in millions of
fingers will be crushed.                             production Chevrolet engines.

Depending on what transmission the car               The roller hydraulic lifter camshaft we
has, sometimes you can get the oil pan               selected was a Crane HR276 (p/n
off this way. At minimum, you can drop it            119621) that has the cast iron gear. It’s a
enough to get the timing cover off, clean            dual-pattern cam and, if used with 1.5:1-
the pan rails and replace the gaskets.               ratio rocker arms, has intake and exhaust
                                                     lifts of .488-in. and .509-in., respectively.
Getting the cam the first few inches out of          Its durations are 276°/284° (advertised)
the block is difficult because of inability to       and 214°/222° (at .050 lift). It has no
exert enough leverage to guide its lobes             overlap at .050-in. lobe lift and is ground
over the cam bearings. To make that                  with its intake centerline at 107° and a
process easier, a pair of 5/16, coarse-              112° lobe centerline angle which means it
thread bolts, 4-6 in. long, can be screwed           has 5° advance built into the profile.
into the front end of the cam to serve has
“handles”.                                           We wiped Red Line Synthetic Oil’s
                                                     Engine Assembly lube on the cam’s
You may get the cam almost all the way               bearing journals and distributor gear, then
out, then find it interferes with the hood           inserted it part way in the block, installed
release mechanism. Position the engine               our “handles” and, carefully, finished the
such that the point of interference is the           job.

                     Converting Lifters from flat to roller

We added a Crane, a double-row, true-             used a magnetic base one can find at any
rolling timing chain assembly (p/n 11993).        tool supply.
Its crankshaft sprocket has three
keyways allowing installation “straight up”       During the degreeing process, we
(which we used, since the cam is ground           checked lobes for #1 and #6 cylinders
with 5° advance already) or with either:          and found cam timing accurate within
four degrees advance or four degrees              6/10ths of one percent, well under
retard. We installed the camshaft                 accepted standards. Clearly, Crane
sprocket and lined its index mark with            makes a quality product.
crankshaft sprocket mark. We left the
cam sprocket bolts only “snug.” The final         We removed the camshaft bolts to install
tightening would be done later.                   a Crane cam button spacer (p/n 99164)
                                                  and locking plate assembly (p/n 99168).
The next step was to “degree” the cam.            Both items must be used with a roller to
This validates both the cam                       control endplay. The camshaft bolts were
manufacturer’s work and your installation.        treated with Valco Cincinnati Thread
Briefly, you establish top dead center            Locking Compound then torqued to 20
using the “positive stop” method then             ft/lbs.
compare the cam’s actual timing with the
manufacturer’s timing data. A “degree             We installed a Fel-Pro timing cover
wheel” is used to measure crankshaft              gasket and test fitted the cover for a
rotation and a dial indicator is used to          check of camshaft endplay. Unlike a flat
measure lifter or valve movement. We              tappet cam, a roller “floats” in the block
recommend degreeing a new cam in any              so endplay is an issue. It’s controlled by
street high-performance or racing                 the cam plug at the back of the block and
application. A full discussion of the             by the cam button spacer and the timing
process can be found in How to Build              cover at the front.
Chevrolet Small-Block Camshafts and
Valve Trains.
                                                  A reasonably accurate endplay
                                                  measurement is possible using a dial
Crane sells a handy package of                    indicator that has a mounting ear on its
measuring equipment, the “Tune-a-Cam              back. Aim the indicator stem through the
Kit.” (p/n 99030), that has everything you        engine block’s right-front oil return hole
need to degree a camshaft with the                such that it touches the back of the
heads on the engine. However, we                  camshaft sprocket. Position the indicator
degreed with the heads off, so we                 body such that the mounting ear drops
needed B&B Performance’s TDC                      into the #2 exhaust lifter bore. Gently pry
Indicator Stop (p/n 40200). We also used          the camshaft back and forth and watch
B&B’s 14-inch Degree Wheel and                    the indicator dial. The measurement will
Chevrolet mounting kit (p/ns 45050,               be a teensy bit off due to the indicator
45010). TDC checking requires changes             axis diverging slightly from the
in degree wheel indexing and we prefer            camshaft’s, but your reading will be of
the B&B set-up because it makes                   acceptable accuracy for endplay
indexing changes easier. Lastly, to mount         purposes.
the dial indicator to the head decks, we

                      Converting Lifters from flat to roller

In some cases with sheet metal timing              (p/n 26300) to 60ft/lbs. and added an
covers, there will be no endplay, so it will       MSD timing tape (p/n 8985), then turned
have to be modified for clearance using            our attention to the cylinder heads and
two sockets and a large bench-vise or a            valve gear.
hydraulic press. Put machinists blue on
the cam button, then push the cover in             Spring Action
place to mark the area to be formed. Use
a 1-1/4-in. socket on the outside and a            We returned the heads to Mark DeGroff’s
9/16-in. socket on the inside. Position the        Cylinder Head Service for a freshen-up
cover between the two sockets and                  and to have the valve springs changed.
sandwich all that in the vise. Compress            We originally chose L82 Corvette heads
the vise and the 9/16ths socket forms a            for the large combustion chambers
depression on the inside of the cover.             needed to get 9.5:1 compression in a 400
Increase the size of the depression a little       with flat-tops. Additionally, of the
at a time until end-play falls within the          production, big-chamber, iron heads; they
desired range. We modified our cover               have the best intake ports. The first time
such that endplay was the .005-.008-in.            around, DeGroff ported and polished the
suggested by Crane Cams.                           castings, added larger, 2.02 in. intake
                                                   valves and did a multi-angle valve job.
Lastly, we cleaned the oil pan gasket              For the freshen-up, Mark disassembled
surfaces and end seal grooves. To keep             the heads, inspected all parts and grit-
debris from falling into the pan, we               blasted the chambers. He then “touched-
followed the gasket scraper with a shop            up” the valve faces and seats and verified
vacuum. We put a set of Fel-Pro                    that valve stem-to-guide clearance was
Performance oil pan gaskets (p/n 1821)             within tolerance.
in place, reinstalled the pan and lowered
the engine back into its mounts. We                Compared to flat tappet cams, roller
reinstalled the fuel pump using a Crane,           profiles have higher acceleration rates
bronze-tipped, fuel pump pushrod (p/n              and higher lifts so more aggressive valve
11985) required for use with roller cams.          springs must be installed. Invariably this
                                                   means a dual spring of larger diameter.
If you’ve seen people install harmonic             Our stock spring seats had to be
dampers with a 10-lb. sludge; don’t go             enlarged to accept them, so Mark
there. You’ll damage the crankshaft thrust         DeGroff machined the heads accordingly.
bearing and probably the damper itself.
Use a B&B Performance Damper                       Valve stem lubrication is a tricky issue
Installation Tool (p/n 40660). It has a            with a street high-performance engine.
threaded pilot, a big nut and a ball-              Liberal valve stem oiling is ok for a race
bearing to smoothly press the damper               motor, but on a streeter, it can cause
onto the crank snout.                              excessive oil consumption and even
                                                   visible smoke. Too little oil will fry the
Using B&B’s degree wheel and TDC                   stems and guides. Originally, Mark
stop, we set the engine at TDC #1, then            DeGroff set stem-to-guide clearance at
compared the timing pointer to the timing          .0015-in. for intakes and .0025-in. for
mark on the damper. The match-up was               exhausts. For sealing, he used OE valve
perfect. We torqued a B&B damper bolt              stem o-rings and a set of late-model, OE

                       Converting Lifters from flat to roller

rubber seals installed on the ends of the          rpm range of our 400. That all were
valve guides. After 30,000 miles, stems            consistent in both seat and open
and guides showed minimal wear and                 pressures is demonstrative of Crane’s
there was no evidence of excessive oil             good quality control. That and choices in
use so, clearly, valve stem lubrication            springs, retainers and locks allowed
was ideal. Since the Crane retainers               DeGroff to assemble the heads without
allow production o-ring seals to be used;          valve spring shims.
Mark duplicated our original seal set-up.
We feel that DeGroff small-block heads,            Back in our garage, we shot a fresh coat
set up like ours, will have 50,000 mile            of Eastwood Chevrolet Orange paint on
durability…outstanding life in a street            the heads then reinstalled them, using
high-performance application.                      Fel-Pro Performance head gaskets (p/n
                                                   1014) which combine Fel-Pro’s, excellent
The Chevrolet valve springs we used with           stainless steel core/laminate design with
the flat tappet cam had greater installed          a steel ring around the cylinder for
height than the Cranes. Also, the OE               improved sealing in high-compression
exhaust valve rotators, typical of small-          engines. Though its intended use is
block heads of the mid-to-late-70s, had            marine and racing applications, this
been removed, resulting in additional,             gasket has the steam holes necessary for
surplus installed height for the exhaust           the 400 small-block in a street
valves.                                            application.

To address the intake valve installed              We used B&B Performance head bolts
height issue, we installed the Crane               (p/n 3810). SB Chevy head bolts screw
spring and retainer (p/ns 99838, 99936)            through the decks and into the water
recommended for use with the HR276 but             jackets and, thus, their threads should be
used a set of special, Crane split-locks           coated with a sealer. We use Loctite PST
(p/n 99096) that reduced installed height          which offers good sealing and adequate
by .050-in. For the exhaust valves, we             seize protection. The B&B bolts use head
used a taller Crane spring (p/n 99893) but         bolt washers and they should be lub'ed
with the standard retainers and locks              before installation. We used Red Line
(p/ns 99936, 99097) that go with the cam.          Assembly Lube for that. We tightened the
                                                   head bolts in the pattern listed in the
If you are converting an iron head                 service manual to 70 ft/lbs. for the long
originally equipped with rotators to Crane         bolts and 65 ft/lbs. for the short ones.
dual springs and no rotators, consult
Crane’s technical support department               We dunked each pair of Crane lifters in
before you order valve springs, retainers          Red Line Synthetic 10W-30 then dropped
and locks.                                         them in place. Crane pushrods (p/n
                                                   11628) specific to this application went in
Mark DeGroff checked all springs. The              next.
measured: 100 lbs., closed and 300 lbs.
at .500-in lift for the intakes and 120 lbs.       We added Fel-Pro intake manifold
closed and 300 lbs at .500-in. lift for the        gaskets (p/n 1205) intended for stock or
exhausts, figures appropriate for the              slightly modified intake ports. They have
camshaft profile we are using and the              Fel-Pro’s clever, Printoseal feature that

                     Converting Lifters from flat to roller

allows them to be reused during induction        resistance to your twirl, that is the zero
system changes. We laid a 1/4-in. bead           lash point. Each nut was given a turn
of Valco RTV silicone sealer on the end-         more, then the locking screw was
seal surfaces, waited 20-min. for it to          tightened.
“skin,” then set the manifold in place. We
opened a set of B&B intake manifold              The valve covers were reinstalled using
bolts (p/n 26050), dabbed Red Line               Fel-Pro gaskets (p/n 1604) and B&B hold
Assembly Lube on the washers and PST             downs (p/n 68500). Information on the
on the threads then torqued them to 30           remaining reassembly can be found in a
ft/lbs.                                          service manual.

Arm’s Length                                     Since we had the exhaust off the car, we
                                                 improved the system’s reliability and
While researching this article, we found         appearance. First, we had our Hooker
comparative data on rocker arm ratios in         Super Competition headers (p/n 2375)
How to Build Chevrolet Small-Block               coated with Hooker’s optional Metallic-
Camshafts and Valve Trains indicating            Ceramic treatment. This coating tolerates
that, in many street high-performance            thermal stress, resists rust, is somewhat
applications, additional power with              impact resistant and has an attractive,
minimal loss of low-end torque comes             polished silver finish. Hooker Industries
with 1.6:1 rocker arms on the intakes            offers this coating on new headers or as
only.                                            a stand-alone service. The headers on
                                                 this car had been treated twice before by
We installed Crane. 1.6:1, extruded              other suppliers with metallic-ceramic
aluminum rockers (p/n 10759) on the              coatings that failed in short order.
intakes which gave us .520-in. valve lift.       Hooker’s process is the only one that has
We used Crane one-fives (p/n 10750) on           lasted.
the exhausts. Both these rockers were
designed for ’86 and up heads but can be         For a durable seal, we use Fel-Pro
used on older heads. Their advantage is          header gaskets (p/n 1407), specific to
they fit underneath the old-style,               flange-plate-type Hooker headers. Lastly,
production, sheet metal or cast aluminum         we use the Stage 8, locking header bolt
valve covers that must be used on                system which never loosen up.
engines equipped with Rochester fuel
injection.                                       Upon reinstallation of the distributor, we
                                                 set the initial timing at 15 degrees. This
The initial valve adjustment was 1-turn of       ensures and easy first start-up, even if
preload. This was accomplished by                the engine is cold. We installed a MSD
adjusting each intake when its companion         distributor cap (p/n 8437), one of MSD’s
exhaust started to open and adjusting            new, racing rotors (p/n 8467) and a set of
each exhaust when its intake started to          MSD Super Conductor spark plug wires
close. Each rocker nut was hand                  (p/n 31659). Then, we screwed in a fresh
tightened until zero lash was reached. A         set of AC RapidFire #1 spark plugs, filled
good way to feel for this is to pull up on       the crankcase with Red Line 10W-30
the pushrod end of the rocker arm while          Synthetic oil, installed a K&N Oil Filter
twirling the pushrod. When you feel a tiny       (p/n 07-0025), and filled the cooling

                      Converting Lifters from flat to roller

system with 75% distilled water, 20%                testing or a precise exhaust gas analyzer
antifreeze and a bottle of Red Line Water           for this purpose.
Wetter. The last ingredient contains a
“wetting agent” that enhances transfer of           With the engine’s fuel curve in the
heat from the engine block and head                 ballpark, we put some more miles on the
castings to the coolant. Because of this,           car getting subjective impressions. The
once the thermostat fully opens, coolant            first thing we noticed was a smoother
temperature stabilizes at a lower level.            idle, slightly lower idle speed and about
                                                    2-inches more vacuum. Drive ability at
The engine fired immediately and we                 low speeds and part throttle also
adjusted the fast idle to 2000 rpm. Then,           improved. At highway speeds, we saw
we backed off the timing to about 20.°              more vacuum and about 1.5 more miles-
Once the engine reached normal coolant              per-gallon. All of these are signs of an
temperature, we ran it up to 3500 rpm               engine that is running more efficiently.
and set the total ignition advance to 34°.
We continued to run the engine at a fast            After about a thousand miles, we got the
idle until the oil temperature reached              car back in the shop checked for leaks
175°. Then we shut it down and checked              again, pulled the valve covers and
for leaks.                                          readjusted the lifters, then, replaced the
                                                    oil filter with a fresh K&N and added
Now it was time for some development                enough Red Line 10W-30 top bring the
driving. The significant change in airflow          level back up to “full”.
characteristics brought by the new
camshaft forced recalibration of the                Obviously, the last step was to validate
engine’s fuel delivery schedule. We                 our modifications and the results of our
equipped the Malibu with an Air/Fuel                testing are covered in detail elsewhere
Ratio indicator (p/n 85-2437) from K&N              (see attachment). Suffice to say that,
Engineering. This devices uses data from            clearly, when done to a street high-
an oxygen sensor installed in the exhaust           performance Chevrolet V8 having
to derive air/fuel ratio and displays it on a       appropriate induction and exhaust system
small, LED panel we mounted in the car’s            modifications, replacing a flat tappet,
dashboard. We used it to set the fuel               hydraulic cam with a a roller hydraulic of
injection’s part-throttle-cruise calibration        similar or slightly less duration pays off in
and the point at which its power                    better performance.
enrichment occurs. With a carburetor
engine, these operations correspond to
changing the main jets and/or power

We also used the K&N A/F Indicator to
make a preliminary wide-open-throttle
fuel mixture adjustment, however, we do
not recommend O2S-driven devices as
the final measure of WOT fuel calibration.
It is better to use vehicle performance


Shared By: