I googled " new zealand cylinder coating " and got this as a start: http://www.kiwibiker.co.nz/forums/archive/index.php/t-26429.html
Cylinder Liner fit to crankcases
- Thread starter Chrish
- Start date
Thank you David, & all of you who replied to my questions. Yes, there is a company here in the South Island, http://www.nzcylinders.com/index.html , who I will now contact. I suspect I will need to do a few more paying Guzzi repair jobs to pay for this! (But would it be any cheaper to go down the traditional path with iron liners anyway, given that the liners need to be removed from the muffs, muffs honed true, new oversize liners bored & honed to fit the pistons & the OD turned to fit the crank case? Then there is the problem of liner fit in the crankcase! Sorry, what was the question again?)
Not being an engineer I am probably a bit out of my depth here, but I remember Tony Maughan pointing out to me that my original liner muffs had lost their fit over the years, he could tell that by the discolouration on the surface of the liner and muff, he then told me that if left it would create hot spots on the liner due uneven heat transfer and possible seizure, that being the case, what chance does the crankcase mouth have of evenly dissipating heat away heat from the lower part of the liner?
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Peter your correct. Putting my engineers head on, to get a decent heat transfer without hot spots the muff to liner interference fit needs to be 6 thou when cold. The liner is then bored and honed after so the bore is perfectly round (hopefully). To be able to assemble the lower part of the liner into the crankcases the liner cannot be tighter than a push slide fit otherwise the finished liner bore will be distorted by the crankcase. So best option is a slide fit. As the crankcase mouth heats up they will expand away from the liner and so very little of the heat transfer from the barrel to the crankcase will go through that area. Most of the direct heat transfer will go through the base of the muff contact area to the top of the crankcase and some will be through the oil circulation. When the engine is hot I cannot see how the crankcase mouth offers any support to the lower part of the liner at all.
Keeping the clearance to push slide fit does reduce the chance of any oil going to the cylinder feed escaping through a gap between the liner and crankcase. The question though what that cylinder oil feed does is another debatable topic.
Simon
Would you block it off ? Not sure what I will wind up with if I go 102mm Stroke, Cheers Bill.
i machine the liner so that the JE pistons skirt just from a mm goes into thin air.
done already 50 K KM without a cylinder oil feed.
or is it cos i rev it up
done already 50 K KM without a cylinder oil feed.
or is it cos i rev it up
When building my Rapide I fitted Maughan's muffs that are machined from solid fitted with their liners. The muffs will still have weaker areas where the stud holes are but overall, I think that they give a better fit for the liners. 30,000 miles on and the engine does not burn any oil. (valve guides fitted with seals). The crankcase JUST nips the liner.