Crankshafts
• Balance
• Weld
• Install Heavy
Metal
• Grind
• Straighten
•
Cut Second Keyway for Blown Engines
• Polish
• Increase stroke
• Wet Magnaflux
• Lighten
Counterweights
• No Holes Balance
• Clean,
Inspect and measure
Many people don't realize that factory balanced cranks can be out as much as 30 grams. For daily drivers this is usually unnoticed but on a high RPM engines it becomes far more noticeable. It can lead to premature crank cracking, main bearing failure and in some cases bolts vibrating out. Here at WRE we balance all of our cranks to less than 3 grams.
For extreme racers that only the best will do, we offer a no holes balance job. This means any weight that needs to be remove is machined off in a lathe which reduces the diameter of the counter weight. This does two things, one, it cuts down on windage friction from oil. Two, it reduces the inertia weight of the crank, making the engine accelerate faster. You can also use our CNC program to lighten counterweights and get the most out of your crankshaft.
Some externally balanced crankshafts need to be internally balanced for racing applications. For this we add tungsten slugs (heavy metal) to the counter weights until it is possible to internally balance the crankshaft.
The first steps before we use a crankshaft, even a new one, is to clean, inspect and measure, even if its a new crankshaft.
New crankshafts are usually covered in a light oil to prevent rust. This comes off easily in a spray washer. Used crankshafts however can have a build up in the oil holes, this needs to removed by agitation in our Hot Tank.
After cleaning the crankshaft we visually inspect every surface for defects in manufacturing, journals having scratches, imperfections and damaged threads. We then move on to measuring.
Diameter, taper, width, surface finish and stroke are some of the measurements that we record before using a crankshaft. If any one of the measurements are unacceptable, the crank is then sent to the crankshaft department to be ground. If its new, it will be returned to the manufacturer!
All engines components need to checked for cracks and imperfection before using them. One way we do this is with an oil based phosphorous mag particle solution. The crank, rods or any other cast iron or steel part are charged magnetically. This fluid is then run over every surface. The mag particles that this fluid carries is attracted to defects and glows brightly under a black light. If the part shows no imperfection then it is demagnetized and can be used. If it is cracked it is not used.
If a crankshaft spins a bearing or goes through a major blow up it will likely need to be straightened. If only a rod journal has damage and the mains measure good then we can straighten the crank and not have to grind the mains.
Many of our classes that we build engines for have close tolerances on how long the stroke can be. We measure and correct the stroke on every performance crankshaft we grind. We adjust the corner radius of our grinding wheels to match the original radius to help maintain strength. We also stop grinding .002" before finish size and check for taper and the stroke before grinding to the finish dimension.
Before polishing we chamfer the oil holes with a special tool that conforms to the elliptical shape of an oil hole. After the crank is polished it is then measured again and visually check for imperfections.
Cut Second Keyway for Blown Engines
On blown engines due to the abnormally high load on the balancer, we will cut a second keyway 180 deg. from the original keyway on both the crankshaft and balancer. We also check the interference between the balancer and crankshaft. It is also important to use a high quality fastener to hold the balancer tightly seated in place.
When a crankshaft or any other shaft gets worn down too far it is usually possible to build the worn area up with our shaft welding machine and grind it back to its original dimension. This is usually cheaper than what it would cost to replace the crankshaft or other shaft.
In some situations where a crankshaft of a particular stroke is not available, we can build the crankshaft up with our crankshaft welder and then lengthen or even shorten the stroke to what ever you are needing it to be.
For people running classes that use stock crankshafts, we have a CNC program that removes material from the center area of the counterweights. It removes weight without making it impossible to balance. This program also works on aftermarket crankshafts. You can use this program with the no holes balance job to really get some weight off.
