Bye Bye to my VX already???

[psychos2]

i can see it getting hotter with it open ,not closed . maybe its a typo. when i cleaned mine the other day i noticed it was sticking in the open position. shawn

[Green Dragon]

"When the EGR fails to open, combustion temperatures cannot be limited, causing higher cylinder temperatures and an increase in NOx emissions. Engine ping or knock may occur, especially when the engine is under load."

This is interesting to me as well, if the EGR sticks in the open position, Cyl head temp rises. If ping or knock occurs then I would presume that the knock sensor would retard the timing, since the timing is initially retarded for emissions control the very least occurance would be a corresponding decrease in the complete ignition of the fuel/air mixture. ( Poor Gas mileage- less power).

I am not sure that the rear seal in this particular instance is an issue when the Isuzu engine PVC fails closed. The seal most certainly has failed in the past (other engines) whenever crankcase pressure has been excessive but I am unaware of crankcase seal failures in Isuzu engines.

It is an interesting discussion but unless Isuzu provides us with the failure analysis data (Highly unlikely) our theroms right or wrong remain unproven.

As for my VX, I think best to apply the aforementioned semi rigid prevention methods I alluded to earlier.

[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 ?