Also, please be aware that the procedures, techniques, and other material on this page, as well as answers to your engine questions, may not work for your particular application, and in some instances, may be hazardous. It is up to you to use your own judgment as to whether information you find here will work for you. With that said, lets get to this months article.
(That's right Chevy)
We're sorry for the delay, and the present lack of images, but at last the Big Block Chevy project is off to a good start. As we said in the earlier engine build up, research and double checking, is the name of the game.
For this project, Bart needed an engine with enough
power to be a thrill ride, and still be reliable. His choice is a 454 Chevy,
bored .030 over, hence the 460 ci. designation. The original block, that
came with his Curtis runner bottom, was sent out for cleaning, boring,
and decking. The deck height had to be cut .019 to get it back into true
with the crankshaft, and this is something that requires some attention
latter on. The crankshaft is a forged steel unit,
that has been cross drilled, and also nitrided to give extra strength.
The rods are Chevy LS 6 units, that have had the beams polished, and shot
peened to give added strength. The pistons, are TRW forged aluminum pistons
that give a 10 to 1 ratio at stock bore. The heads are cast 454 heads,
that have been ported, polished, and flowed, with stainless steel valves
measuring 2.19 intake, and 1.88 exhaust. Getting the air in and out of
the cylinders is accomplished by an Edelbrock Performer RPM camshaft with
a lift of 560 on the intake, 573 on the exhaust. Duration is 240 and 246,
at .050 lift, respectively, giving a 6500 RPM power peak. Flowing the intake
mixture to the cylinders is accomplished with an Edelbrock Performer RPM
intake manifold, and Holley 750 carburetor. Bassett short collector headers
remove the exhaust gasses.
OK, lets take a closer look at the project. First,
Bart did all the block prep, such as grinding,
and
drilling, before the block was sent out for machining. Bart used a die
grinder and sanding rolls to polish the valley area, in order to promote
better oil drain back to the pan, and also polished the bowl area where
the oil pump mounts to the block. He also enlarged the oil drain back openings
in the front of the block to help 
keep
more oil in the pan. Then the block was sent out to the local machine shop
that we feel does an excellent job. Greg Spreen, the owner of Spreen Engine
& Machine, cleaned the block by cooking it at high temperature, and
then blasting it. After checking all the tolerances, it was determined
that .019 had to be milled from the deck to get the deck square with the
crank again. The main bearing journals were not straight, and align honing
was required. The cylinders were bored .030 over, using torque plates
in the process. Torque plates are one of those things, that while not absolutely
necessary, give a more concentric bore. With all the machine work on the
block completed, the next step was to balance the rotating mass. Very little
metal had to be removed to get the crankshaft balanced to the new rods
and pistons, as well as the fly wheel. Remember, the fly wheel, and the
harmonic balancer on some engines needs to be balanced with the rest of
the rotating mass.
With the machine work done, it is time to start
assembling the bottom end. The block was cleaned with solvent one last
time, by forcing it through the oil passages. This was accomplished using
a suction gun, and high pressure air. The oil passages were then brushed
and pressure cleaned one more time. Next, the block exterior was primed
and painted, being careful not to get paint inside the block where it can
come in contact with the oil. As we said on an earlier engine build, painting
the inside of an engine can increase oil drainage back to the pan, but
paint flakes can also block an oil pick up screen, or damage a pump. Again,
the use of a die grinder and sanding rolls does a much better job, although
it does take more time. Next, the crankshaft was cleaned in a manner similar
to cleaning the block, high pressure air/solvent, and brushing. Bart is
using ARP main studs to hold the main caps in place, instead of regular 
bolts.
The studs will give more reliability to the bottom end over the long run.
Note that two of the studs have an added threaded area. These are a special
order part from ARP, and must be used to support the oil pick up on engines
with the pump at the rear, and sump at the front of the engine ( the back
of the boat when the engine is in). When using an after market fastener,
make sure you follow all of the manufacturer's procedures, and recommendations.
Bart's choice for bearings, both main and rod, is Clevite 77s. During installation
of the crank, a liberal amount of 30 WT. motor oil is applied to all bearings,
while the studs have ARP's special lube applied to them. Once the crank
is in, and the fasteners torqued down, the pistons and rods are installed.
The pistons have been fitted with Speed Pro rings,
with the top ring gap set at .018. Be sure
to check the rings for proper end gap before installing, or you could have
a high dollar boat anchor on your hands. If the rings are gapped to close,
the ends will butt together when running, destroying the cylinder bores.
Also, to keep from scratching the crankshaft, two small pieces of soft
tubing, cut in two inch lengths, are slipped over the rod bolts, before
the piston is inserted into the bore. The pistons and rods were put in
one side at a time, and the crankshaft pre oiled before the second side
was completed. By pumping oil into the crankshaft with an oil can, the
inside of the crank is protected, and helps keep a film of oil on the main
and rod bearings during assembly. As we said earlier, the milling of the
deck will present some extra work.
Once the pistons are installed, it is necessary to check the height of
the edge of the piston in relation to the deck. Once the piston is raised
to TDC, a dial indicator is used to determine the height of the piston
edge above the deck. Its necessary to rock the piston in the bore, to get
the edge as high as possible This measurement will be used when setting
up the head gasket thickness. If the height above the deck is to high,
a thicker head gasket will have to be used to keep the pistons from hitting
the quench area of the head. With the crank shaft, pistons, and rods installed,
its time to move on to the cam installation.
The cam is the one engine component that is going to determine how your engine performs, and needs careful attention. The cam degreeing process is simple, and should always be performed when putting an engine together. In Bart's engine, the literature with the cam specifies a cam lobe center line of 110 degrees. This means the intake lifter on the number 1 cylinder should be at maximum lift when the crankshaft is 110 degrees past TDC. To make sure the cam is within tolerances, a degree wheel is attached to the crank shaft, and a pointer, made of wire, is fixed to the block. Next, an aluminum bar is bolted across the top of the number 1 cylinder. The crank is rotated until the piston stops, and a reading of the degree wheel is taken. The crank is then rotated in the opposite direction until the piston stops, and a second reading is taken. The difference between the readings is where the crank needs to be positioned, to be at Top Dead Center. The crank is rotated to this point on the degree wheel. Then, the degree wheel fastener is loosened, and the wheel turned until 0 degrees is lined up with the pointer, and the fastener tightened back up. With a lifter placed in the number 1 intake lifter bore, a dial indicator is used to measure the height of the lifter as the engine is rotated. Once the lifter has reached its highest point, the crank is turned slowly until the lifter lowers .050. A reading of the degree wheel is taken, and the crank is then turned in the opposite direction until the lifter peaks and begins to drop to .050. A second reading is taken, and the difference between the two reading is where the center line of the lobe is. Cam timing is very important, since sometimes a bad cam slips through quality control every so often. I have had a cam to be 9 degrees off from where the center line should have been, and had I not caught it, the performance of the engine would have been poor at best.
The next thing to be installed is the oil pump.
Bart is using a Melling High Volume pump, that 
should
supply plenty of oil to where is needs to be. When using a high performance
oil pump, it would be a good idea to use a bigger drive also. The small
diameter of OEM drives may not stand up to the stress of higher volumes
and pressures. Bart is using a 10 quart oil pan, that has baffles and trap
doors installed to help prevent oil starvation. When it comes to oil, don't
forget to use the best filter possible. Most parts houses carry a premium
brand filter, that has a spring holding the filter element in place inside
the filter housing. A remote two filter system would be even better, if
you don't mind the added expense.
Next time, we'll cover the installation of the
heads, and the rest of the valve train.