Different bore sizes or the alignment?

clevermax · 27th August 2008, 08:54

I happened to see a Palio 1.9D's engine opened up yesterday. When I looked at the base, as shown in the picture, two of the bores (marked in yellow) are deepeer than the other two.

Different bore sizes or the alignment?-dsc00209.jpg

Are the bore volumes unevenly distributed? Or is it just the positioning of them? I always thought that the bore volumes will be equal.

Nikhilb2008 · 27th August 2008, 08:56

naaah..... just that the pistons in those two are closer to (Bottom Dead Centre)BDC than the middle two.

IT is perfectly fine.

If you could rotate the crankshaft, you would see the position change.

nitrous · 27th August 2008, 09:09

This picture will help you understand.

Rehaan · 27th August 2008, 20:03

Clevermax,

Nikhil & nitrous have done a good job of explaining this, i just wanted to add (for the sake of information) that the bore is the diameter of the cylinder, and what you are refering to as the "depth" could also be termed as the stroke (ie the entire length of vertical travel).

Area from Bore x Stroke = Displacement (Volume)

cya
R

clevermax · 27th August 2008, 20:25

Quote:

Originally Posted by Rehaan

Clevermax,

Nikhil & nitrous have done a good job of explaining this, i just wanted to add (for the sake of information) that the bore is the diameter of the cylinder, and what you are refering to as the "depth" could also be termed as the stroke (ie the entire length of vertical travel).

Area from Bore x Stroke = Displacement (Volume)

cya
R

Thanks a lot for the explanation! Now I understand it the right way. (Bore, Stroke)

Quote:

Originally Posted by nitrous

This picture will help you understand.

The picture does not help me understand why two of the 'cavities' are deeper. In your picture, if you rotate the crackshaft 180 degrees, you can see the other two pistons coming up to the same position as the ones in the top position shown in the picture. So why should the stroke be deeper in two of 'em?

Quote:

Originally Posted by Nikhilb2008

naaah..... just that the pistons in those two are closer to (Bottom Dead Centre)BDC than the middle two.

Can you please explain more on BDC?

Nikhilb2008 · 27th August 2008, 22:37

The piston moves up and down in the cylinder. When it is closer to the top(at the end of the compression stroke for example), it is known as TDC. Top Dead Centre. It cannot go above this particular point.

Same way, BDC is the bottom most point the piston can reach while working. BDC is reached at the end of expansion stroke and end of suction stroke.

The pistons are connected to the Crankshaft by use of a connecting rod. So, here the pistons at the extreme ends of the cylinder are near the bottom of the cylinder than the middle two pistons.

clevermax · 28th August 2008, 08:31

Quote:

Originally Posted by Nikhilb2008

The piston moves up and down in the cylinder. When it is closer to the top(at the end of the compression stroke for example), it is known as TDC. Top Dead Centre. It cannot go above this particular point.

Same way, BDC is the bottom most point the piston can reach while working. BDC is reached at the end of expansion stroke and end of suction stroke.

The pistons are connected to the Crankshaft by use of a connecting rod. So, here the pistons at the extreme ends of the cylinder are near the bottom of the cylinder than the middle two pistons.

Now I got it right. Thanks!

clevermax · 30th August 2008, 17:45

A better illustration of what I saw.

Different bore sizes or the alignment?-engineb.jpg

(I drew it myself

)

27th August 2008, 08:54	#1
clevermax Senior - BHPian Join Date: Jun 2006 Location: Tvm/Amsterdam Posts: 2,086 Thanked: 2,640 Times View My Garage	Different bore sizes or the alignment? I happened to see a Palio 1.9D's engine opened up yesterday. When I looked at the base, as shown in the picture, two of the bores (marked in yellow) are deepeer than the other two. Are the bore volumes unevenly distributed? Or is it just the positioning of them? I always thought that the bore volumes will be equal. Last edited by clevermax : 27th August 2008 at 08:55.
	() Thanks

27th August 2008, 08:56	#2
Nikhilb2008 Distinguished - BHPian Join Date: Jul 2006 Location: Bangalore Posts: 5,196 Thanked: 10,138 Times	naaah..... just that the pistons in those two are closer to (Bottom Dead Centre)BDC than the middle two. IT is perfectly fine. If you could rotate the crankshaft, you would see the position change.
	() Thanks

27th August 2008, 09:09	#3
nitrous Senior - BHPian Join Date: May 2004 Location: UAE/Lon/Madras Posts: 6,965 Thanked: 325 Times View My Garage	This picture will help you understand. Attached Thumbnails
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27th August 2008, 20:03	#4
Rehaan Team-BHP Support Join Date: Feb 2004 Location: Bombay Posts: 24,046 Thanked: 34,078 Times	Clevermax, Nikhil & nitrous have done a good job of explaining this, i just wanted to add (for the sake of information) that the bore is the diameter of the cylinder, and what you are refering to as the "depth" could also be termed as the stroke (ie the entire length of vertical travel). Area from Bore x Stroke = Displacement (Volume) cya R Last edited by Rehaan : 27th August 2008 at 20:04.
	() Thanks

27th August 2008, 22:37	#6
Nikhilb2008 Distinguished - BHPian Join Date: Jul 2006 Location: Bangalore Posts: 5,196 Thanked: 10,138 Times	The piston moves up and down in the cylinder. When it is closer to the top(at the end of the compression stroke for example), it is known as TDC. Top Dead Centre. It cannot go above this particular point. Same way, BDC is the bottom most point the piston can reach while working. BDC is reached at the end of expansion stroke and end of suction stroke. The pistons are connected to the Crankshaft by use of a connecting rod. So, here the pistons at the extreme ends of the cylinder are near the bottom of the cylinder than the middle two pistons.
	() Thanks

30th August 2008, 17:45	#8
clevermax Senior - BHPian Join Date: Jun 2006 Location: Tvm/Amsterdam Posts: 2,086 Thanked: 2,640 Times View My Garage	A better illustration of what I saw. (I drew it myself )
	() Thanks