Bye Bye to my VX already???

[mbeach]

I always thought that one of the side benefits of a properly working EGR system was cooler cylinder temperatures.

When I bought the first VX, the Isuzu tech(s) told me to immediately change the oil with Mobil 1 0W-30. Maybe this was to combat the oil drainage issue right off the bat.

Wait a minute...
3 piston rings, top to bottom
Compression
Compression
Oil Control/scraper

Crank case

Why exactly does oil need to drain through a hole in the piston/ring land in order for it to be returned to the crank case -shouldn't it drain down there on it's own with every downstroke of the piston?

[Green Dragon]

Wait a minute...
3 piston rings, top to bottom
Compression
Compression
Oil Control/scraper

Crank case

Why exactly does oil need to drain through a hole in the piston/ring land in order for it to be returned to the crank case -shouldn't it drain down there on it's own with every downstroke of the piston?

That is what I thought initially, but my research into this subject turned up this interesting NASA report that addresses this issue ( albeit a different engine)

This is a good read.Especially pages 4,5&6.

http://naca.larc.nasa.gov/reports/19...ge00000004.gif

[mbeach]

Excellent detective work -I learned quite a bit.

Are the 3.5's pistons aluminum or steel?
Also, has anyone tried replacing the scraper ring with one that is .003 thicker, so that it doesn't move so much with the ring land?

I'd like to see oil consumption measures rated by the hour, rather than by the mile. I think that the stop and go nature of some driving contributes more to the pumping phenomena than anything else.

[SGT.BATGUANO]

Only thing I can add is that the recycled exhaust gasses aren't as hot as the 1500 +/- degrees in the combustion chamber, so reintroducing METERED AMOUNTS of preburnt exhaust lowers the COMBUSTION CHAMBER temp by reducing oxygen content of the fresh charge ?