I'm wondering if anyone here might have information on that. I realize they are different engines, V6 vs inline 4, but I'm wondering if they have similar cylinders and use the same rings.

The reason I ask is because there was a recal on something like 80k Nissans with the 2.5 engine because they were losing oil from bad piston rings. And I'm having a similar problem on my Z.

 

I have the same problem....

 

in order to answer that question all you need to do is compare the bore of both engines.

and the answer to that is no.

 

Engine Bore:

VQ: 3.76"
QR: 3.50"

Not the same.

 

cool, thanks for the info.
I'm wondering if they just had some general manufacturing problems on the rings.

 

It's possible that they sourced them from the same manufacturer, and the manufacturer screwed up.

I never had any oil problems with my SpecV (QR25) nor do I have any with my Z (VQ35).

 

I know there have been years of Nissan engines with no problems. But I've read that between Feb and May of this year there was a manuf. problem with rings that has caused oil consumption. Nissan had to recall 80k Sentras and Altimas w/ the QR25. There were 17 cases of engine fire as a result of the low oil. These are extreme cases, of course, but there's still a problem.
i guess it's the luck of the draw. Happen to get the exception to Nissan's usually quality product.

 

The problem with the QR, lies in it's short rod/stroke ratio. This puts a lot of sidewall loading on the piston, and makes it hard for the rings to stay seated at higher RPM. Also, Nissan has been experimenting with different ring tension in the QR over the past few years, to try and get this problem solved. They haven't succeeded yet.

With that said, the VQ doesn't have this problem, as it has a much better rod/stroke ratio than the QR25DE.. and it uses a much better ring.

Travis