Sorry I haven't been around for awhile (if anyone missed me), I took a new job and let the old IROC sit in the garage for awhile but when I went to get it back out I noticed something strange...when I checked the oil there was about 1.5 quarts of gas in it (after sitting for many weeks). It was 15W-50 Mobil 1 with 60 miles on it, and I had to drain it which made me sick. I know the injectors leak some but all pressure is gone off the fuel rail overnight (so they should be done leaking by then), but no oil in the gas if I just let it sit for a couple days. Also, taking the gas cap off (my garage is uninsulated and about 100F in the day) seems to help, which makes me think pressure in the tank can somehow keep pressure on the fuel injectors as well.

The question is, how long does it take gasoline to leak past the piston rings and into the oil pan (e.g. - will it sit there for awhile or just run right by)? Some guys out at work said it can't get past the rings, but I seriously doubt that... Knowing the answer to this will help me come up with a solution.

Thanks guys.

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1990 IROC 350
Mods: Too busy trying to make it run right to mod it.
Airfoil, Dynomax cat-back, Accel coil, 180 t-stat, Bald Eagle tires,
Hypertech fan switch, Accel 23# injectors, Holley AFPR, ported plenum,
Ruger P95DC, hot wife, new oil filter, thick rubber floormats.
18.0 @ 85MPH since I'm one big-a$$ MF
"It's better to have and not need than to need and not have."

 

Anyone? Thanks.

 

I worked for a roofing company for 2yrs. All we did was commercial/industrial roofs. I can tell you that water (or gas, or whatever) can get through just about anything it want's to. If gravity is on it's side, fluids will win. I guarantee that gas CAN get by the rings. Whether it's through the ring gaps, piston to ring clearance, or just seeping past the rings on the cylinder walls, it will get by. The only way it couldn't/wouldn't is if the engine was upside-down.

Same thing applies to the injectors. The gas that's sitting in the lines, even after the pressure goes down, will seep through the injectors. And yes, gas does build quite a bit of pressure from heat. And it doesn't drop after the gas cools. It just keeps building up. Even under stable temps, the pressure will build from natural evaporation and vaporization.

1.5 quarts is a lot though. I hope you are exagerating, even a little. I don't know how that much could get by. But I'm guessing it would be relative to the amount of fuel in the tank. More fuel would mean more pressure, more evaporation, etc. But that's still a lot.

Hope this helps. It's really the only explanation, and not just the only one you got here. The only one I can think of anyway.

AJ

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92 RS w/t-tops 305 TBI Auto.
170K miles and don't burn a drop o'oil
-K&N Truck filter #1500 w, open ele.
air cleaner
-Dynomax 2 1/2" cat-back
-B&M TransPak
-Jet Stage2 Chip
-180* T-Stat w/ 185* Fan Switch
-JVC CD--Alpine speakers & 4ch. amp
Rockford 2ch. to 2 MTX 12" subs

 

Thanks for the response, AJ. Well...maybe it was about a quart but it was more than I needed to see. Think my theory about the pressure in the gas tank continually forcing fuel by the injectors slowly over time has any merit? I really appreciate your input.

 

Yea. That's what I was pretty much saying here. It would make sense that the fuel lines would be the easiest place for the pressure to go. And of course we know what's on the end of the fuel lines. Kinda like electricity takes the path of least resistance. I would imagine pressure does to.