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Piston rings

Started by Dmitry, September 26, 2015, 08:29:19 AM

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Dmitry

#15
October 27, 2015, 05:59:29 AM Last Edit: October 27, 2015, 06:03:28 AM by Ducatista26
Quote from: ducpainter on October 24, 2015, 07:04:58 AM
300 ml/ 1000 miles is not enough consumption to warrant a rebuild, or even investigation IMO.

You obviously feel differently, so go right ahead and do what you want. It's clear we're not going to dissuade you.
Hi again. Look at the picture please. How to understand it? Coupling Clearance = 0,25÷0,045 mm and max. clearance = 0,12 mm. Why is max. clearance less than normal clearance? I do not understand it ??? Maybe it mistake? ;D

ducpainter

#16
October 27, 2015, 06:06:25 AM
Quote from: Ducatista26 on October 27, 2015, 05:59:29 AM
Hi again. Look at the picture please. How yo understand it? Coupling Clearance = 0,25÷0,045 and max. clearance = 0,12 mm. Why is max. clearance less than normal clearance. I do not understand it ???

There's a misprint on the metric dimensions. It should read .025 + .045. The inch dimensions are correct.

.0023 inches is optimum and .0047" is max.
"Once you accept that a child on the autistic spectrum experiences the world in
 a completely different way than you, you will be open to understand how that
 perspective
    is even more amazing than yours."
    To realize the value of nine  months:
    Ask a mother who gave birth to a stillborn.
"Don't piss off old people The older we get, the less 'Life in Prison' is a deterrent."


Dmitry

#17
October 27, 2015, 06:15:16 AM Last Edit: October 27, 2015, 06:18:10 AM by Ducatista26
Quote from: ducpainter on October 27, 2015, 06:06:25 AM
There's a misprint on the metric dimensions. It should read .025 + .045. The inch dimensions are correct.

.0023 inches is optimum and .0047" is max.
Thanks! And what do you think about it. If this clearance is more than max. allowed. So new rings will not help in this situation? I properly understanding your opinion in this topic?

ducpainter

#18
October 27, 2015, 06:21:52 AM
Quote from: Ducatista26 on October 27, 2015, 06:15:16 AM
Thank! And what do you think about it. If this clearance is more than max. allowed. So new rings will not help in this situation? I properly understand your opinios in this topic?
If you have more than the allowed clearance new rings would be a complete waste of money.It used to be that Ducati had pistons that were designated A and B. The A pistons would be used in cylinders that were closer to the lower end of tolerance, and the B pistons used in cylinders that were at the upper end. Are your piston crowns marked with a letter? Have you measured the bore or the pistons using the appropriate tool?
This type of measuring requires specialized equipment. You can't guess.
"Once you accept that a child on the autistic spectrum experiences the world in
 a completely different way than you, you will be open to understand how that
 perspective
    is even more amazing than yours."
    To realize the value of nine  months:
    Ask a mother who gave birth to a stillborn.
"Don't piss off old people The older we get, the less 'Life in Prison' is a deterrent."


Dmitry

#19
October 27, 2015, 06:35:17 AM
Quote from: ducpainter on October 27, 2015, 06:21:52 AM
If you have more than the allowed clearance new rings would be a complete waste of money.It used to be that Ducati had pistons that were designated A and B. The A pistons would be used in cylinders that were closer to the lower end of tolerance, and the B pistons used in cylinders that were at the upper end. Are your piston crowns marked with a letter? Have you measured the bore or the pistons using the appropriate tool?
This type of measuring requires specialized equipment. You can't guess.
It is my piston. In my opinion - do not marked.

ducpainter

#20
October 27, 2015, 06:39:48 AM
I'll have to check a set I have, but I think that's a B piston.

Have you had the dimensions checked by someone with the proper tools?
"Once you accept that a child on the autistic spectrum experiences the world in
 a completely different way than you, you will be open to understand how that
 perspective
    is even more amazing than yours."
    To realize the value of nine  months:
    Ask a mother who gave birth to a stillborn.
"Don't piss off old people The older we get, the less 'Life in Prison' is a deterrent."


Dmitry

#21
October 27, 2015, 06:47:42 AM Last Edit: October 27, 2015, 06:49:45 AM by Ducatista26
Quote from: ducpainter on October 27, 2015, 06:39:48 AM
I'll have to check a set I have, but I think that's a B piston.

Have you had the dimensions checked by someone with the proper tools?
Today I will check clearance and write you about it. But I think that clearance is more than max. allowed. On your experience these years (95-98) all of Monsters have such problems like me? Or just me not lucked.

ducpainter

#22
October 27, 2015, 07:01:45 AM
Quote from: Ducatista26 on October 27, 2015, 06:47:42 AM
Today I will check clearance and write you about it. But I think that clearance is more than max. allowed. On your experience these years (95-98) all of Monsters have such problems like me? Or just me not lucked.
What tools are you going to use to check? To get accurate info you need micrometers and bore gauges...not just feeler gauges.

You're the one that thinks there is a problem.

I think you should put it back together and run it.
"Once you accept that a child on the autistic spectrum experiences the world in
 a completely different way than you, you will be open to understand how that
 perspective
    is even more amazing than yours."
    To realize the value of nine  months:
    Ask a mother who gave birth to a stillborn.
"Don't piss off old people The older we get, the less 'Life in Prison' is a deterrent."


Dmitry

#23
October 27, 2015, 07:03:41 AM Last Edit: October 27, 2015, 07:05:31 AM by Ducatista26
My piston-cylinder coupling is 0,15 mm. It is more than max. allowed (0,12 mm) :(

Dmitry

#24
October 27, 2015, 07:05:16 AM
Quote from: ducpainter on October 27, 2015, 07:01:45 AM
What tools are you going to use to check? To get accurate info you need micrometers and bore gauges...not just feeler gauges.

You're the one that thinks there is a problem.

I think you should put it back together and run it.
Yet only have feeler gauges.

Dmitry

#25
October 27, 2015, 07:09:18 AM
Quote from: ducpainter on October 27, 2015, 07:01:45 AM
I think you should put it back together and run it.
It seems you are right. Otherwise I must to change the whole engine ;D

ducpainter

#26
October 27, 2015, 07:13:55 AM
Feeler gauges are not the best way to determine the part that is out of spec...if it's really out of spec.

You tore your engine down for excessive oil consumption when there was not really a problem. 300 ml in 1K miles is perfectly normal for these engines. It's why they'll last for 300K with proper care. You didn't have a compression problem, and you never took a leakdown test to determine where the little compression you thought you lost was going.

You didn't replace valve seals, which is most likely the cause of what little consumption you were experiencing, before you tore it down.

Now you're basing your thoughts on the least accurate method of measuring.

My advice to you is to either take your parts to a machine shop to get them measured correctly and then make a decision, or put it back together with new valve seals and see what kind of results you get.

My 96 will burn a pint in 1000 miles and I don't worry about it a bit. It starts and runs good, doesn't foul plugs, and is fun to ride.

Good luck.

One question...are you an engineer? :P
"Once you accept that a child on the autistic spectrum experiences the world in
 a completely different way than you, you will be open to understand how that
 perspective
    is even more amazing than yours."
    To realize the value of nine  months:
    Ask a mother who gave birth to a stillborn.
"Don't piss off old people The older we get, the less 'Life in Prison' is a deterrent."


Dmitry

#27
October 27, 2015, 07:47:25 AM
Quote from: ducpainter on October 27, 2015, 07:13:55 AM
Feeler gauges are not the best way to determine the part that is out of spec...if it's really out of spec.

You tore your engine down for excessive oil consumption when there was not really a problem. 300 ml in 1K miles is perfectly normal for these engines. It's why they'll last for 300K with proper care. You didn't have a compression problem, and you never took a leakdown test to determine where the little compression you thought you lost was going.

You didn't replace valve seals, which is most likely the cause of what little consumption you were experiencing, before you tore it down.

Now you're basing your thoughts on the least accurate method of measuring.

My advice to you is to either take your parts to a machine shop to get them measured correctly and then make a decision, or put it back together with new valve seals and see what kind of results you get.

My 96 will burn a pint in 1000 miles and I don't worry about it a bit. It starts and runs good, doesn't foul plugs, and is fun to ride.

Good luck.

One question...are you an engineer? :P
No ;D Why do you think so? :)

ducpainter

#28
October 27, 2015, 07:50:14 AM
Quote from: Ducatista26 on October 27, 2015, 07:47:25 AM
No ;D Why do you think so? :)
I don't necessarily think so. It was just a question because many engineers can't leave well enough alone and feel the need to explore the cause of everything be it a problem or not.
"Once you accept that a child on the autistic spectrum experiences the world in
 a completely different way than you, you will be open to understand how that
 perspective
    is even more amazing than yours."
    To realize the value of nine  months:
    Ask a mother who gave birth to a stillborn.
"Don't piss off old people The older we get, the less 'Life in Prison' is a deterrent."


Dmitry

#29
October 27, 2015, 07:57:09 AM
Quote from: ducpainter on October 27, 2015, 07:50:14 AM
I don't necessarily think so. It was just a question because many engineers can't leave well enough alone and feel the need to explore the cause of everything be it a problem or not.
Nonetheless my end gaps of oil rings in the cylinders = 1,3 mm when max. allowed in the manual = 1 mm [bow_down]
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