Part 1, Let's Tear Down
We hear this question all the time: how can I build my engine without spending a lot of money? The bottom line: It takes a lot of searching for parts and aiming your goals a little below that of a 700hp big-block to accomplish it.
Recently, we ran into an enthusiast who asked us that very question, and his story is not unlike that of just about every enthusiast. He had no "extra" money to spend, and the engine in his '66 Barracuda had passed needing to be rebuilt about 70,000 miles ago. At last count, it used three quarts of oil for a 70-mile trip-like we said, it needed rebuilt or replaced. The problem was, Darryl, the Young Gun who owns this car, uses it as his everyday car, and therefore, it could not be torn down for a long period of time.
The base for our build was...
The base for our build was a '70 318 that was given to us some time ago. We found that it was in good, rebuildable shape as soon as we took it apart.
The easy fix? Get another engine to build, and then just swap them out later. Lucky for him, we just happened to have a 318 sitting in the corner of a warehouse that we could use. The replacement engine came out of a '70 Charger that a reader gave us a few years ago because he was putting a Magnum-headed crate engine in his car. Since the engine didn't cost us anything, it didn't cost Darryl anything. But we really didn't know what we would find during teardown. Would the engine be a basket case? Would it be rebuildable? The only way to answer these questions was to tear it apart and hope for the best.
When the engine was completely disassembled, we were more than happy with what we found. It was apparent that either this engine had very few miles on it or it was well taken care of. Either way, we were in luck. After we removed the heads and intake, we dug into inspecting the bearings. The condition of the bearings is a telltale sign of what the rest of the engine probably looks like. For us, the copper underneath the "Babbitt" material was barely showing and "mic-ing" the crankshaft journals confirmed a standard-journal crankshaft.
More often than not, a rebuild will consist of a mild over-boring of the cylinders and the purchase of aftermarket pistons. With that being said and as proponents of making cylinders bigger to allow for more cubic inches and higher compression, we have to say there are a few times when you may not need to oversize the bores. In our case, after the rod and piston assemblies were removed, we hoped for the best and decided to "mic" the cylinder bores and see what the verdict was. From the factory, a 318 has a cylinder bore of 3.910 inches with an out-of-round allowance of .005. Keep in mind, there is no money for this build, so when the worst cylinder measured 3.912 inches with an out-of-round factor of .002, we knew we were in luck.
As soon as we pulled the heads...
As soon as we pulled the heads off, we knew that things were going well because the cylinder walls showed no visible scarring and the pistons looked to be in good shape. Many times, the cylinders will have worn a lot and a "ridge" will be found at the top of the cylinder. If you find a ridge that seems like it's excessive, plan on over-boring the cylinders and getting larger pistons.
When we pulled the timing...
When we pulled the timing chain cover off, we found the timing chain had been previously replaced. It looked fairly new, but we didn't feel right reusing it.
After we removed the timing...
After we removed the timing chain and gears, we started to pull the lifters to see what we had. Again, things looked good as there was no discernable wear.