I'm getting gasoline in my oil. Why?

[patspond]

My 1981 project coupe was coming along slow but sure when I noticed the smell of gasoline on the dip stick of my (recently) modified 350/ 345hp . I have changed the fuel pump twice and flushed the crankcase several times with oil and filter changes. Is there another way that the gasoline can get into the oil and how can I correct this problem? thanks,, Ed

 

[ggaagg57]

if your carb is dripping gas into the secondarys went you turn it off the gas can get in to the oil, but it would be hard to start. or if you are running a real rich mixture that to can get into oil. hard to say with out the car . but something to look for. george

 

[cruzer99]

What is your intake? Carb, EFI, Turbo, Supercharger, etc.

 

[patspond]

George,, This is great. Joined the forum about four hours ago and very helpful info is coming in. Thank you for your input. At least I wont have to change the fuel filter,,,, Ed

 

[patspond]

gas in oil

Cruzer82,,, I'm sorry that I didn't include that info in my problem discription. The Intake is carb. thanks,,Ed

 

[cruzer99]

Are you running an electric fuel pump? If so do you know how much pressure it puts out? If it is high you should think about a pressure regulator. How many miles on the motor? What changes have you done recently to the engine? (new carb, tune-up, etc.)
Sorry about all of the questions but we are all shooting in the dark out here.

 

[AKRAY4PLAY]

Ed,
what is your current fuel/air mixture like?? do have a raw fuel smell from the exhaust when the car is idling?? if your mixture is rich, then your problem is most likely from poor ring seat. you mentioned that the motor is recently modified, so that means the jetting has most likely been adjusted, to me. too rich and the unburnt fuel sits on the rings and the pressure from combustion pushes it past the rings. if enough fuel gets into the oil, your viscosity goes bye-bye along with the rotating assembly = VERY BAD DAY!! what are your upgrades?? if the cam was changed the vacuum may have gone way down, and if you are running a carb with power valves, they might be staying open all the time and adding far to much fuel for your needs. let us know what kind of carb you have and what the intake vacuum is at idle (auto tranny needs vacumm checked when in gear). best of luck and we'll help as much as possible, Brian

 

[patspond]

gas in oil

cruzer82,,The engine has a manual fuel pump. I bought the car "as is". The engine has been completely rebuilt, 0 miles, I believe a holly 650, mild cam, Hei ignition. I believe the car sat quite awhile after the engine work as the seller was in the middle of restoration when he burned out and I bought it.

 

[patspond]

gas in oil /Brian

I will have to get back to you on some of your ideas. I'm beginning to think, after my first day on the forum, and all the suggestions that the car sat for a long time after the engine was rebuilt while the seller worked on other restoration projects. Maybe the carb is gummed up and dumping excess fuel (I hope) after the engine is shut down. thanks ,,Ed

 

[Stallion]

What exactly are the PCV parts? I remember my dad talking about the PCV valve and I never knew what it was. Could someone explain? And also, what's a dip stick?

Thanks!

TR

 

[AKRAY4PLAY]

another thing i forgot to mention. if the motor has backfired and you have Holley, then chances are you also have blown power valve(s) leading to a rich mixture. it is a cheap and easy fix if so. tuning tip, with knowing your intake vacuum selection of power valves is easy. run a valve that is two numbers less than your vacuum. example on a cammed motor, 8.5 inches of vacuum, run a 6.5 valve. the valves are easy to check to see if they are blown. pull the float bowl and metering block off, unscrew the valve and suck on it. it should move the checkvalve when you apply vacuum. if you can suck air thru the valve, it's wasted. good luck finding the sorce of your troubles, Brian

 

[WayneLBurnham]

Concur overwhelmingly likely PCV system

Bad PVC valve itself, plugged oil breather or vacuum system plumbed wrong or a huge vacuum leak.

That is the main and most common cause of volatile buildup in a modern engine - and both the cheapest and easiest to fix.

For $50-100 you've replaced the entire thing and included a nifty chromed or billet oil filter breather and PVC valve to dress up the engine a little. Not only that, but changing all those vacuum lines is an excellent idea anyhow - you may find a little missing vacuum aside from the probable malfunction in your PVC system.

I noticed both Summit and now Eastwood has silicon vacuum lines in many sizes - even in colors!!! That's so import/redneck/plain-assed TRASHY *I'm* gunna HAVE to do it!!! :Silly

The silicone hose is a great idea anyhow though, even if you're not a dreaded "modifier."

 

[Jack]

ED:
Look for carb's float stuck in down position, hole or leak in float if it's a hollow can type float, or gas-logged/saturated if it's cast resin type float, carb's needle & seat leaking. Also, when carbed C3 is parked with nose lower than tail ... if carb is leaking ... it can siphon gas back to carb (my 71 did it when float stuck open & parked nose down) ... but gas in oil can happen even when parked nose up or level ... check float also needle & seat. All these things can happen with car parked & motor off ... my 71 did.
JACK:gap

 

[Vette/Berlina-coupe]

-Its the Fuel-pump obviously...

-Its obviously the fuel-pump (would be astonished if not), just slap-on a new one and be done wit it! -If it has obviously diluted the oil, then before even starting the engine again, immediately (if not sooner) drain the oil and change filter; --the minor residule gasoline remaining in the lifters and oil-lines will readily be boiled-off. Before you restart the engine with the new-oil, pull-off the coil-lead and crank the engine to build-up oil-pressure and thereby flush-out the diluted-oil. The camshaft-lobes are probably the first thing to become damaged by the gasoline dilution, -so when you do start the engine let it idle for a few minutes, so that the new-oil has time to become well distributed. Electric/Fuel-pumps can be dangerous (as they keep pumping gasoline even if engine is killed; -like during an automobile-accident!), I always at least use a kill-switch with an elect./fuel-pump. An elect./Fuel-pump located near the gas-tank are useful however on a car that may sit for a number of days, as you can use it to prime your carburetor prior to start-up, --then once started shut it off (the mechanical-pump will just suck-fuel right through the elect./fuel-pump's check-valves...
:s :Roll :dance

 

[Jack]

Re: -Its the Fuel-pump obviously...

[B Electric/Fuel-pumps can be dangerous (as they keep pumping gasoline even if engine is killed; -like during an automobile-accident!),
:s :Roll :dance [/B]

Thankfully, most if not all modern cars have a shock/vibration sensor switch (similar to the sensor that triggers air bag) that disconnects power to fuel pump when there's an sharp shock. Some are so sensitive even a minor bump will disable the pump ... this often leaves the stranded driver wondering wtf. The reset switch is often in the trunk or rear compartment. Some of the earliest versions were so sensitive you could take your hand and rap the fender hard enough to disable the pump.
JACK:gap

 

[LT4hitsthespot]

What exactly are the PCV parts? I remember my dad talking about the PCV valve and I never knew what it was. Could someone explain? And also, what's a dip stick?

Thanks!

TR

PCV- positive crankcase ventilation ... a one way valve

Dip stick - The stick that goes from top of the engine into the oil pan. How you check and measure your oil level

 

[Stallion]

About the PCV, what exactly does it do? It just brings air into the crankshaft case? Why? :confused

Thanks!

TR

 

[Interceptor430]

Hey Stallion,
maybe you should start a new thread with your questions???

 

[81NMVETTE]

Heya Stallion

Let me try to describe the PCV. or Positive Crankcase Ventilation System.
All Engines have closed Positive Crankcase Ventilation System to provide more complete scavenging of crankcase vapors. Ventilation air is drawn from the clean air side of the air cleaner, through a hose down into the crankcase, up thrugh the ventilator valve (PCV), through a hose and into the intake manifold. Intake manifold vacum draws any fumes from the crankcase to be burned in the engine.
The PCV Valve is a one way valve it will let air pass only one way.
Some of the other air managment systems that are on my 81 are , Exhaust Gas Recirculation system (EGR), Early Fuel Evaporation System (EFE),
The Air Managment System (air pump) is a belt driven pump and its air is controled by the ECM it directs the air where it is needed.

Sorry I just dident know where to stop with the post

Anyway they came up with some neet ways to remove the gases that buldup in the crankcase I know in the old days they would just vent the crankcase gases into the atmosphere (sp) but with the new rules about Emissions they found that runing the gases back into the engine to be burnt would lower the total emission.
You might ask why is there pressure in the crankcase ?. Have you seen on some of these post's where somebody says blowby ?. well as the rings wear they let gases slip past them this creates pressure in the crankcase I had an old Bronco that had a really bad ring and it got so bad that it blew the hose off of my PCV Valve.
I am sure I left some parts out but you get the general idea about how and why a PCV works I took most of my info out of my 81 service manual as it has a great section on Engine Emission's

Hope that clears the PCV part up for you.


Earl

BTW Stallion did you and your father go to that auto auction yet ?

 

[Stallion]

Thanks a lot, Earl! I think I pretty much understand the useage and functionality of the PCV valve now. Thanks again!

TR

And no, the auction is Feb 21, 22, and 23. We're going the 21 and 22. Can't wait!