from Company C. If you are a
crankshaft manufacturer, you concentrate on building the
best possible crank - and you don't really worry about
whether your crankshaft counterweights will clear the
Company C's piston skirts. Similarly, Company C focuses
on building lightweight pistons - providing clearance
for Company A's new crankshaft counterweight design
isn't on its radar screen.
So who has to make sure that
the crankshaft counterweights clear the piston skirts -
along with the block, the camshaft, the oil pan, the
windage tray, and everything else? The engine builder.
It's better to assume that
parts don't fit than to assume that they do. That's not
being negative - it's just being realistic. The problems
you find when you first assemble an engine are
relatively easy and inexpensive to solve. It's the
problems you discover after the engine has blown up that
are back breakers. For example, if you simply assume
that the crankshaft flange thickness is correct for your
torque converter instead of actually measuring the
clearance, don't be surprised if you burn out the thrust
bearing.
Even a part as apparently simple as a distributor can
cause serious problems. The housing for a Chevrolet
distributor has a groove that transfers oil to the
right-hand oil gallery. If this groove is misaligned
because the block/head/manifold combination positions
the distributor too high, |
the right-side lifters,
pushrods, rocker arms, and springs are going to starve
for oil - and they can't survive very long without
lubrication. Perhaps the distributor gear doesn't engage
the drive gear on the camshaft properly - how do you
know unless you check? One of the final steps in engine
assembly at Reher-Morrison Racing Engines is to verify
the position of the distributor. We don't install the
oil gallery plugs in the back of the block until the
very end of the assembly process so we can visually
confirm that the distributor's position relative to the
block and cam is correct.
Professional engine builders
have the advantage of seeing more variations in engine
components and are therefore more likely to spot
potential problems. If you are building your own engine,
my advice is to take your time and check every part you
bolt on. Don't rush to make this weekend's race if it
means taking shortcuts. It's the pieces that almost fit
that can be the most troublesome - the camshaft drive
that's cocked just a little on the block or the pushrod
guideplate that's just a little out of alignment.
When I started racing, we had
three network television stations and one universal
racing engine. Now I can choose between 200 channels on
cable TV and literally thousands of engine components.
My dog Duke doesn't worry about such things. He just
wants to know when I'm going to stop writing and |
