[gnarly]

hey gents,

I'm doing my very first top end rebuild.
Looking at the vertical piston rings gap clearances and found these measurements. I need to know if they are ok or do I have to file them down a bit. Only had time to do the vertical today. They are straight out of the factory (out of the box). Both vertical and horizontal rings.

Vertical:
1st ring - .23
2nd ring - .20 to .23
3rd rings: a) .30
b) .30


Are these ok? I don't understand the screenshot measurements but I assume that 0,2 dived by 0,4 means .2 to .4
Anyone can help decipher that workshop manual measurements? I greatly appreciate it.


Regards,
Gnarly

 

[tye1138]

That guide is only if you aren't replacing the rings. If you have the motor apart, I would absolutely put new rings in it.

 

[Joeii]

Europe uses a comma in lieu of the decimal point; 0,2 is the same thing as 0.2.

 

[gnarly]

Tye, I knew you'd be the first to reply. Thanks man.
I bought new rings and they're right of of the box, straight from the factory.
I measured the gaps and those are my findings. However, last night when I looked up vids on measuring ring's gap clearances, the feeler gauge has to have a bit of resistance when you pull it off of the gaps. When I measured them, it didn't quite have that resistance.

Thank you also Joeii.
With that said, does that "0.2 to 0.4" figures mean that it could be 0.20 or 0.23 or 0.24 etc... up to 0.4x?

 

[devimau]

Means upper between 0.2 to 0.4 MM is ideal when assembling new rings and when inspecting ring gap up to .8 should be ok, above that replace for sure.

Use same criteria for others.

 

[pat1098]

You don't say which model you have, but your clearances sound pretty good, and well within the range described.

Make sure each ring is exactly 'square' in the bore by carefully easing the top of the piston up the bore against it before doing your measurement.

But the Nikalsil bores do not normally wear much on these, unless there is a catastrophic failure.

I will be going into mine next week, and will be replacing my rings also as mine has done over 76,000 kms. (Mine shows no signs of wear or oil consumption).

I will post up my clearances. Essentially you should have a tighter ring gap on the new rings than the old ones. Of course.

The end gap on the compression (upper two) rings is more critical than the oil ring (lower).

 

[gnarly]

oops, my bad Pat. It's a 2005 749D.

ok.
here's my final check:

vertical
1st ring: .30 to .33
2nd ring: .45 to .50
3rd rings:
a) .48 to .50
b) .48

horizontal
1st ring: .33 to .35
2nd ring: .40 to .43
3rd rings:
a) .45 to .48
b) .43 to .45

My first read outs, I don't think I did correctly.
Never had to use a feeler gauge on anything so I didn't know that it's supposed bite in the gap.

All appear to be "within" factory specs. I didn't have to file the rings at all, phew....
As far as I'm concerned, they're different all around but still within specs from Ducati. I'm gonna try it again tomorrow and will post differences.

 

[gnarly]

Pat, Have you done your top end rebuild yet?

 

[pat1098]

My rebuild has stalled, due to Ducati's parts supply.

They told me they can't supply rings alone, as the piston and rings were changed for '08, and I have to buy pistons as well. Even though my pistons are in lovely nick.

But they have only been able to supply one piston assembly. There are "none available in the world" apparently.

So I am waiting while they make some more..

Hard to be happy with that. I will keep people informed of progress in the Pat's Engine Overhaul thread.

When there is some.

Lucky it's still winter here, and I have another bike to ride.