I've rebuilt at least a couple hundred car and dirtbike motors, plenty of which were race motors. But I've never rebuilt a ducati motor.
2000 m750, I'm reusing the old rings, but when I disassembled it the rings spun without my noticing so I have no idea what their orignal positioning was. engine has 20k miles on it, and rings have plenty of life left. cyls both still have some cross-hatching visible, but nowhere near enough to re-seat rings from what I can tell based on experience with other engines.
I have the haynes manual which shows ring end gap positioning as simply being 120 degrees apart, but doesnt state which ring is placed how. I was planning to put the oil control ring gap straight forward, and the top rings at their respective angles towards the rear of the engine. and the haynes manual flat out states DO NOT HONE THE CYLINDERS, whether it's for new or used rings, but to bring the cyls to a ducati dealer for refreshing if they need it.
so my question is: should I hone the cyls at all or no? if yes, what type and/or grit hone should I use? the cyls appear to have a 30 degree from horizontal crosshatch, so if I were to hone the cyls, I'd just use that same approx 30 degree angle.
I'm pretty certain all Ducati cylinders are Nikasil coated.
Quote from: Raux on June 13, 2012, 10:23:39 PM
I'm pretty certain all Ducati cylinders are Nikasil coated.
ok? so what does that mean in regards to seating new or used rings?
I kind of assumed they were plated due to the strength of suggestion in manuals to not hone. but I know what it's like to install rings that wont seat because there's not enough crosshatch roughness, and I really dont want to deal with that in a ducati haha
One of the board mods is DuckStew. He knows tons more than I do about the issue. PM him or give it a day. You'll get your answer.
Also, do a quick search in tech on replating cylinders as well. Might help with some questions like that
Your cylinders are Nikasil coated. Usually, as long as the coating did no fail you can re use them as is. The coating does not wear much.
A good way to determine if your rings or cylinders are worn is place the rings squarely in the cylinder. Measure the gap. It should be 1 mm. or less. If so, reassemble. As far a position of the ring on the cylinder goes, just make sure the gaps on the first and second rings are opposed to each other.
ok awesome. is there any special procedure I should use once it's all back up and running to seat the rings? or any idea how long it'll take for the rings to fully seal again? obviously in an ideal world with perfect tolerances, the rings should seal perfectly all the way around right off the bat, but even ducati doesnt have that magic wand I'd assume lol
typically car engines require the process of: heavy throttle to about 3/4 of the capable rpms, then decel using only engine braking back to cruise rpm, cool-off period cruising, then repeat 3-5 times, and rings are fully seated. should I pretty much just do this same thing?
Quote from: howie on June 14, 2012, 06:51:19 AM
Your cylinders are Nikasil coated. Usually, as long as the coating did no fail you can re use them as is. The coating does not wear much.
A good way to determine if your rings or cylinders are worn is place the rings squarely in the cylinder. Measure the gap. It should be 1 mm. or less. If so, reassemble. As far a position of the ring on the cylinder goes, just make sure the gaps on the first and second rings are opposed to each other.
I would have said exactly the same thing had Howie not already posted. Spot on.
Check per Howie's instruction.
Do not hone.
Re-align rings to spec.
Re-install.
Perform this: [Dolph]
Haha! love that emoticon! sweet, thanks guys :)
see.. told you give it a day
ps no chrome rings.. i've used Deves rings for years and have been very happy with their longevity.
the only thing I wish I had was a total seal second ring, I used those on VWs and it made a huge difference
Quote from: ducatiz on June 14, 2012, 01:45:37 PM
ps no chrome rings.. i've used Deves rings for years and have been very happy with their longevity.
good to know
Quote from: ducatiz on June 14, 2012, 01:45:37 PMthe only thing I wish I had was a total seal second ring, I used those on VWs and it made a huge difference
I've never been a fan of total seal rings. they only work properly in a specific temperature range. and I mainly work with high hp turbocharged motors designed to also be daily drivers, which have insanely large temp variations
Quote from: motoxmann on June 14, 2012, 03:02:33 PM
I've never been a fan of total seal rings. they only work properly in a specific temperature range. and I mainly work with high hp turbocharged motors designed to also be daily drivers, which have insanely large temp variations
i used them in VW drag engines without much trouble.. no forced intake though, but stroked out to the gills. plenty of high temps and more fluctuation...
the main issue was seating them right. i used 30wt ND oil to break in for about 10 minutes.
i've never used them in a Ducati engine though, just hypothetical. the Deves rings have performed very well for street bikes I've had.