Why crankshaft deflection

These include;. Thus, any changes from natural deflections can be related to main bearing misalignement and is proportional to the differences in height of the bearings. And fit as shown in fig. The gauge is fitted and zeroed. If the reading is not zero then it indicates that the gauge is moved and the readings are re-taken.

Crank Position. No1 Cyl. No2 Cyl. No3 Cyl. No4 Cyl. Another good rule of thumb is to compare your readings with those of your previous crankshaft deflection measurement. This way, you can detect abnormal or high deflections that might have occurred in a short time span.

With that said, many engineers prefer to double-check these results by drawing a deflection curve that provides a graphical representation of the results. Once you have conducted your crankshaft deflection measurement, you can explore the wide array of causes for deflection, if present.

Below is a small sample of what could cause deflection in the crankshaft. In this article, we explored the importance of regularly running a crankshaft deflection measurement. To this end, we looked in detail at the composition of a crankshaft and what purpose it serves.

In a more practical manner, we learned about the deflection gauge as the main tool for carrying on these measurements and how it should be used. Finally, we provided a step-by-step guide of the crankshaft deflection measurement procedure, as well as some tips on interpreting these results. Home About News Blog Contact us. An innovative approach to yacht maintenance. Contents: What is a crankshaft? The DI-5 and DI-5C from Prisma Tibro is easy to use and can be programmed and reprogrammed to check the position of each mechanism at any time.

Using the DI-5 or DI-5C to regularly check for crankshaft deflection requires only a few minutes of your time and can extend the life of the engine by years. It required reading the crankshaft at each of five positions sides, top, and two on either side of the bottom , and then interpreting these numbers manually to see how the crankshaft should be adjusted. Furthermore, the gauge required the engineer to access the mechanism from every angle, covering him in dirt and grease.

By automating and computerizing the measurement device, the process takes only a fraction of the time and measurements are much more accurate. As you can see from the picture a dial gauge is inserted between the crank-webs to find out the distance between them. If the deflection is measured after the specified interval, it is necessary that it is taken at the same point otherwise the reading will not give a real reflection about the degree of deflection.

Normally a center punch is used to make markings so that each time the deflection is taken at the same point. Apart from using the same point on the crank-web for measuring deflection there are other factors which need to be kept in mind and these include load on the ship, trim, hog, sag etc.