It’s time now to have a look at the engine rebuild. Dayle says I shouldn’t get too technical with this, it becomes boring. Well, I’m not writing about a lump of play dough here, so I need to delve into the technicalities just a little. Let’s start by dividing the V8 engine into two pieces, the bit that houses the pistons that go up and down, turning the crankshaft and eventually turning the wheels, which I’ll refer to as the bottom half, and the bit that houses the valves that lets the fuel & exhaust enter and leave the engine, which I’ll refer to as the top half.
When building an engine, you have to determine what your application will be, or what you intend to do with the car. It’s a pretty safe bet that I won’t be racing the Corvette at Daytona. I’ll be content to cruise the suburbs and highways. Most of my driving will be at about two to three thousand RPM. With this in mind I know what limits I need to go to with the engine rebuild.
The first step with the bottom half was to clean all the bits thoroughly by placing them in an acid bath. Then, the essential parts were measured for their tolerance within the manufacturer’s specifications. In this case, the bore of the engine wasn’t too bad. It just had to be honed out to get that nice perfectly round shape that it needs. The crankshaft had to be ground because it had suffered some wear. New pistons, rings, bearings, gaskets etc. were sourced. Then, the bottom half placed onto an engine stand and carefully assembled. (ie the reciprocating mass)
There is an important component in the bottom half called the Camshaft. I like to think of the Camshaft as the conductor of an orchestra.
When building an engine, you have to determine what your application will be, or what you intend to do with the car. It’s a pretty safe bet that I won’t be racing the Corvette at Daytona. I’ll be content to cruise the suburbs and highways. Most of my driving will be at about two to three thousand RPM. With this in mind I know what limits I need to go to with the engine rebuild.
The first step with the bottom half was to clean all the bits thoroughly by placing them in an acid bath. Then, the essential parts were measured for their tolerance within the manufacturer’s specifications. In this case, the bore of the engine wasn’t too bad. It just had to be honed out to get that nice perfectly round shape that it needs. The crankshaft had to be ground because it had suffered some wear. New pistons, rings, bearings, gaskets etc. were sourced. Then, the bottom half placed onto an engine stand and carefully assembled. (ie the reciprocating mass)
There is an important component in the bottom half called the Camshaft. I like to think of the Camshaft as the conductor of an orchestra.
The Camshaft tells the valves when to open & close, which in turn lets fuel into the cylinder, ignites it under compression, thus forcing the piston back down, and then lets the spent gases flow through to the exhaust. The camshaft design will determine where the power range of the engine is. I.e. is the power required at high revs (like in a race car) or at lower “highway cruising” revs. I chose a camshaft with specifications to suit highway cruising.
To do the job properly, the camshaft can’t be just shoved into the engine. To ensure that it was installed correctly and would work within the manufacturer’s specifications, it was necessary to very accurately measure the point at which the valves would open and close. This is done with a device called a degree wheel, and a dial indicator. A typical instance would be where the inlet valve must just start to open 10 degrees before the piston reaches the top of its stroke.
In my case, I had to advance the position of the camshaft 2degrees, to ensure correct timing.
To do the job properly, the camshaft can’t be just shoved into the engine. To ensure that it was installed correctly and would work within the manufacturer’s specifications, it was necessary to very accurately measure the point at which the valves would open and close. This is done with a device called a degree wheel, and a dial indicator. A typical instance would be where the inlet valve must just start to open 10 degrees before the piston reaches the top of its stroke.
In my case, I had to advance the position of the camshaft 2degrees, to ensure correct timing.
This being done, the engine was painted, the gearbox bolted up, and the engine/gearbox assembly placed back into the car.
Next step will be to attach the top h
alf of the engine. We’ll cover that off in the next installment.
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