millsy
4x4 Earth Contributer
Years ago I heard somewhere that Nissan motors are deliberately built with 'soft' piston rings. The idea being that the rings wear out without doing very much abrasion to the cylinder bores. So it is easier to recondition the engine. Just add new rings, and no need to do a rebore.
Has anyone else heard this story? Is it an old wives tale maybe? Can't remember where I heard it, too long ago. But from various 'observations' over the years I always suspected it might be true.
As an example, the Z motor rebuild information I have found on the Web states that L series Nissan bores are so hard that when it comes time for new rings you can still see the original cross hatch pattern. Although this suggests that the bores are hard, rather than the rings are soft. Either way, both give the same results I suppose.
The reason behind this query is wondering as to why my L28 could be burning so much oil. It has only done 260,000km. My two Holden 'red' motors went so much further - before the rings actually broke up ( in both cases ) - 470km and 407km respectively. I don't recall them causing any great oil consumption before they actually broke.Certainly not as bad as the Nissan L28 in my MQ.
So at the moment I am thinking about three causes - valve steam seals worn out, rings worn out ( or both ), or maybe even just a blocked PCV valve. I thought I proved the PCV valve was OK last year. But I will do it again, just in case all the suction I felt on my thumb was because I put my thumb on the wrong side of the break when I opened up the 'plumbing'!
And I really need to buy a compression tester and do the 'dry' test, and then the 'wet' test. Although wouldn't the wet test cause a certain increase in compression readings even in a good motor?
Has anyone else heard this story? Is it an old wives tale maybe? Can't remember where I heard it, too long ago. But from various 'observations' over the years I always suspected it might be true.
As an example, the Z motor rebuild information I have found on the Web states that L series Nissan bores are so hard that when it comes time for new rings you can still see the original cross hatch pattern. Although this suggests that the bores are hard, rather than the rings are soft. Either way, both give the same results I suppose.
The reason behind this query is wondering as to why my L28 could be burning so much oil. It has only done 260,000km. My two Holden 'red' motors went so much further - before the rings actually broke up ( in both cases ) - 470km and 407km respectively. I don't recall them causing any great oil consumption before they actually broke.Certainly not as bad as the Nissan L28 in my MQ.
So at the moment I am thinking about three causes - valve steam seals worn out, rings worn out ( or both ), or maybe even just a blocked PCV valve. I thought I proved the PCV valve was OK last year. But I will do it again, just in case all the suction I felt on my thumb was because I put my thumb on the wrong side of the break when I opened up the 'plumbing'!
And I really need to buy a compression tester and do the 'dry' test, and then the 'wet' test. Although wouldn't the wet test cause a certain increase in compression readings even in a good motor?
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