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.
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Part 1
Sooner or later, your boat is going to need an engine overhaul. It may be from a mechanical failure, or it has just seen too many days on the lake. In my case, its from a mechanical failure, one that led to the bottom end of the engine being totally destroyed. No matter what the case may be, there are a few basics that need to be followed for any overhaul.
First, you'll have to get the engine out, and completely torn down. All the parts that come out need to be inspected, regardless of whether you want to re use them or not. By examining all the parts, you can get an idea of where any unseen damage may lie, saving time in the long run.
Once the engine has been inspected, its time to decide on whether you want to overhaul the engine back to its current performance figures, or make it have a little more muscle. If your going to go with a stock overhaul, you should have an idea of what your parts order is going to be. If your going for more power, its time to hit the books.
Whatever you do, research is critical when putting together a new engine configuration. You need to make sure that all the new parts are going to work with each other, and not against each other. Sure, a Holley Dominator atop a tunnel ram looks great, but it may decrease your horsepower, instead of increasing it. Over carburation is probably one of the biggest mistakes made when it comes to engine performance bolt ons. The next biggest mistake is too large a camshaft.
Sit down and determine what your using the boat for. Are you going to be pulling skiers, cruising, or putting the pedal to the floor all day. Most likely, your going to be cruising at least 75 percent of the time, and running all out 25 percent of the time. No matter what the case, decide on what RPM range you want the power to occur at, and how often your going to use it. From there, you can select the parts your going to need to fulfill those requirements.
For my case, I wanted around 450 horsepower, and I wanted reliability. Those are pretty easy figures to achieve without a whole lot of money. The first thing I did was to look for a new crankshaft. I decided to go with a LeMans style factory crankshaft made by Ford for the 427 Side Oiler. This is one crankshaft that's plenty strong for my needs, and is good for 7000 RPM. I then ordered a set of used 428 Cobra Jet rods to go with the crankshaft. Since I wanted a redline of 6500 RPM, I looked at several cams that produced power in that range. Remember that you can change the cam timing to get the exact power peak you want. I went with a Lunati cam and lifter package, that gave a peak in normal timing of 6200. With it retarded 4 degrees, it should peak at 6600. The cam is a split lift, 568 intake, 600 exhaust. I am also using Lunati valve springs, and decided on the single spring units. A double or triple spring is nice, but unless your going with a monstrous cam, and very high RPM, you don't need them. I decided on a Cloyes adjustable timing chain set for driving the cam. I then ordered a set of TRW forged pistons in a 10:1 stock compression ratio, at .060 overbore. A set of Speed Pro roller rockers was ordered to top of the valve train, and a complete gasket set for the engine also.
Next came the engine block preparation. I looked around for a good machine shop to do the necessary machine work to the block and heads. This is one area where you need to ask questions. Don't be shy about asking how much its going to cost, and what he's going to do for all that money. For my choice, I chose a new shop in the area, Spreen Engine and Machine. After talking to the owner, Greg Spreen, I felt he could do the job well, and we discussed what I wanted done to my engine.
Before you take in your engine for machine work,
do any grinding, or machining that you can do first. Once your engine comes
back, its going to be clean, and you don't want to fill it with metal filings.
For my engine, there were several things I wanted to get done before I
sent the block out. First, I wanted to get the oil galleys to the main
bearings straight. On most engines, the openings for the oil galleys can
be considerably out of alignment, and not give the 
maximum
amount of oil flow to the bearing and crankshaft. I used a die grinder
to get the opening to match the holes in the main bearings. The next area
I concentrated on was the oil pump mating area, and galley to the filter
adapter. The Ford FE series of engine, with the exception of the 427 Side
Oiler, had a dismally small 3/8" opening from the pump to the oil
filter adapter. I drilled out the galley to 1/2", and chamfered the 
opening
to promote smooth oil flow. I then concentrated on the openings 
at
the filter adapter. I ground the openings so that oil would flow through
the filter adapter with less turbulence. I then worked on the used rods
I had bought. Using a die grinder with a sanding roll, I took the forging
slag off the sides of the rods, and then polished them. This will help
eliminate any stress risers that may have formed during the forging process.
The block, crankshaft, rods, and the rest of the rotating mass was now
ready to go the the machine shop.
I had the block bored .060 over, and all the critical specifications checked. The main bearing webs and deck showed to be in good alignment, and no other machining to the block was required. The rods were shot peened to give added strength, and then re-sized. One thing to remember, if your going to use an after market fastener, like ARP, take them in with the block. The fasteners need to be installed for some types of machine processes. Also, make sure to tell the machine shop that the engine is going to be used for marine use, since the bores may need to be slightly larger, depending on what type of piston your using. Greg then balanced the rotating mass, which included the flywheel and harmonic balancer. All the components for completing the short block were now ready, but I had to wait for the heads, since the valves hadn't come in yet.
Once I had all the parts back at the shop, it was time to start cleaning. Even though the block had been cleaned at the machine shop, I did it again. Once I had the block cleaned, I masked off all areas that I didn't want paint to get into, and them primed and painted the block. Although painting the inside of the block used to be an accepted practice to help promote rapid oil drain back, I don't recommend it. Paint on the inside of the block can come loose, and clog the oil screen, or get sucked into the pump and lock it up. Once the paint was dry, it was time to install the crankshaft.
Before installing the crankshaft, it was cleaned
a second, and then a third time. Very often, the grit used to polish the
mains bearing surfaces, and the rod bearing surfaces, will get inside the
oil galleys inside the crankshaft. If you don't get it out, its going to
wear the bearing a great deal when you start the engine for the first time.
I then installed the crankshaft, using ARP 
main
studs. The stud kit will give far superior strength to the mains than a
standard bolt. During the installation, a small amount of ARP assembly
lube was applied to the main bearing surfaces. Assembly lube is one of
those things that can't be left out during an overhaul, as it keeps the
friction down to a minimum during the first few seconds of an engines first
start. It also keeps all the surfaces from having corrosion form on them
during the assembly process. After the crankshaft was installed, it was
pre-oiled. It helps to have an extra person around for this operation.
Have one person use their fingers to block off the oil journals 
at
their openings for the rod bearings. Then using an oil squirt can, fill
up the crankshaft with oil, through any open rod bearing oil journal. This
will protect the inside of the crankshaft from corrosion, as well as keep
the bearing surfaces oiled during the assembly process.
Next, I prepped the pistons and rods for installation. I started this by filing the rings to the proper gap. Again, here is where a marine engine differs from its automotive brother. Marine engines don't run very hot, and the rings need a little more gap in the top ring. If its not done, there is a chance the ring ends will butt together, and cause the rings to scuff the cylinders. When filing rings, try to use a tool specifically for this operation. If a filing jig can't be found, then hand filing will have to be done. To do it correctly, place the file in a vice, in a horizontal position. Then using slow strokes, file the ring from the outside towards the inside, with the ring held horizontal also. Try to keep the edge of the ring your filing as square to the file face as possible. When you have the gap correct, lightly dress the filed area with an ignition point file to remove any burrs from the edge of the filed area.
With the rings filed, and installed on the pistons,
the pistons and rods were installed into the block. To keep from scratching
the crankshaft, two short pieces of vacuum hose were cut and 
slipped
over the threaded end of the rod bolts. The rod caps were installed and
torqued to the proper specification. With that done, the oil pump was then
installed, and torqued also. When installing the oil pump, don't use a
great deal of silicone sealant, or preferably, use none at all. If you
do use it, use only enough to give a paper thin coating, since you don't
want a big piece being squeezed out where it can come loose and lock the
oil pump.
With most of the bottom end completed, the camshaft
was installed next. As with all other components, make sure to use a liberal
amount of assembly lube. The cam was installed, and then degreed to make
sure the cam met the specifications as quoted on the card that came with
the cam. It is very important to degree the cam, since sometimes errors
occur during the manufacturing process, and if not detected, your engine
will run poor at best. To degree the cam, a strap is made to go across
the top of the number 1 cylinder, and bolted in place. Next, the degree
wheel, and lower timing gear with chain is attached to the crankshaft,
and a pointer, made of wire, is mounted to the block. The crankshaft is
then turned in one direction until the piston hits the strap over the cylinder.
A reading is then taken from the degree wheel. Then, the crankshaft is
rotated in the opposite direction until the piston hits the strap again,
and a second reading of the wheel is taken. The difference between these 
readings
is Top Dead Center. Rotate the crankshaft until this figure is lined up
with the pointer. Now you can loosen the bolt holding the degree wheel,
and rotate only the degree wheel until 0 degrees is lined up at the pointer,
and tighten the wheel back down. Now install a lifter in the number 1 intake
valve location, and install the upper timing gear and chain. Now you will
need to set up a dial indicator, so the upward travel on the intake lifter
can be measured. In some instances, you may need to make an extension,
as I had to do. When you have the lifter and indicator set up, rotate the
crankshaft until the lifter raises all the way up, and begins to lower.
After it lowers to .050 from the highest point, take a reading of 
the
degree wheel. Now turn the crankshaft the opposite direction until the
lifter raises, and then lowers to the .050 mark again, and then take a
second reading of the wheel. The difference between these two points is
the cam centerline, and should match the one that's shown on the cam specs.
Now you can either advance or retard the cam to get the power curve fine
tuned. Advancing the cam timing will shift the curve to the lower RPM range,
while advancing it will shift it to the higher RPM range.
Now that I have my cam installed, I can proceed
with the assembly of the rest of the engine, which will be covered in Part
2 of this article.