PISTONS,CONNECTING RODS,CYLINDERS






PISTONS

Pistons are round, and fit down into a cylinder. That's a round hole in the block . Pistons are about 4 inches round is an average size and are about 4 or 5 inches tall. (See fig. 1)

top of piston
The length is called the skirt of the piston. The skirt's purpose is so the piston doesn't tip side ways in the cylinder . ( see fig . 2)

skirt of piston
If it didn't have a skirt or the lenght. It would be a thin round piece of metal just plugging up a hole and would tip side ways and would not work very well. It would be like when you cut the top out of a tin can. The top will fall side ways but, if it had sides it wouldn't.
And each piston has at least 3 grooves with in the first inch or inch and a half of the piston from the top down. (See fig. 3)

These grooves are for rings. The two top grooves are for compression rings and the third one is an oil scraper ring.

rings of piston


How to fit piston and rings into cylinder
The rings are made of cast iron metal that have some spring to them. Because you have to squeese them together after you have them on the piston. With a ring compressor and then hit the top of the piston lightly to slide the piston down onto the cylinder and when the piston and rings side out of the ring compressor and into the cylinder the rings spring outward against the cylinder walls to make a air tight fit. (See fig. 4)

ring compressor

CONNECTING ROD




The Connecting Rod is what connects the piston to the crankshaft. (See fig 6.)
connecting rod.gif
The connecting rod is held to the piston by the wrist pin. (Shown in fig 5 ) The wrist pin , connecting rod, and piston are put together by holding the connecting rod up in side the piston aligning with the holes in the piston and pressing the wrist pin through one hole in the side of the piston then through the connecting rod and then through the other hole in the other side of the piston.( See fig 5.)

This takes a lot of pressure and some special equipment to do this.

wrist pin.gif
The connecting rod is connected to the crankshaft , which takes the up and down motion of the piston and turns it into rotary motion to drive the wheels of the car.
The bottom part of the connecting rod is split in half and is held together with bolts and must be torqued (or tighted) to the proper foot pounds around the crankshaft. ( See fig 7.)

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