Fuel in oil?

[LarsonJL7]

I have a '73 1.7l with dual carbs setup and was having ignition issues over the past 3 months that turned out to be a defective new dizzy that I had to send back in for repair and the car has been in the garage not running that whole time.
Yesterday I got the repaired dizzy installed and the car fired right up but I was getting oil shooting out of my oil fill vent at high rpm while checking the timing and smoke out the exhaust at any RPM.

I ended up checking the oil level and found I was about 2 quarts high on the dipstick and changed the oil.
The oil came out like water and appeared to be half fuel half oil. Still getting smoke out the exhaust though.

Not sure what would causes this to happen.

Any ideas on what to check next??

[Dave at Pelican Parts]

Fuel in the oil like that is not so good. It is either caused by dumping way too much fuel into the engine, or not burning the fuel that is going in. Some of the fuel in the chambers can leak past the rings if there is no combustion pressure to help them seal.

Over the long term, you can cause damage to bearings and such, because gasoline is not a very good lubricant. You might also wind up messing up the ring to cylinder wall seal. If the smoke coming out the tailpipe is blue, that is a concern.

Are your ignition woes over? Do you know if your engine is running really really rich?

--DD

[frank]

Did you leave your key in the on position by mistake when it sat for all that time or do you have the key in the on position for extended periods, for example to listen to your stereo while you work on it? Doing this keeps the fuel pump on and if the needles in your carbs don't seal properly then the float bowl will overflow and cause fuel to drip into the combustion chamber.

If you have to have your car in the on position for extended periods, remove the fuel pump relay until you identify the source of your leak.

Although the above may not apply to you, the following will...

Because fuel is so thin it can seep past the rings and / or through the ring gaps; the volume depends on the amount of wear. The fuel which drips into your pan will thin your oil... in your case it was incredibly thinned out as it sounds like you had 2 quarts of fuel in there. This creates a condition where your oil is thin enough now to also seep past the rings causing it to burn in the combustion chamber and out the exhaust in a cloud of dark smoke. Fundamentally you are lubricating your motor with fuel and that is really bad which has potential for disaster. This echoes what Dave has stated above. Your spark plugs will also be covered in oil.

Is this a recent carb conversion? Could your fuel pump be putting out too much pressure?

So these are my theories anyway. Maybe they will spark some ideas during your assessment.

I hope you find your issue.. but change the oil before running the motor regardless of what you discover.

[LarsonJL7]

I'm pretty sure the key was left on for an extended period of time. My 2 year old likes to pretend he is driving it while I work in the garage and I came out to the garage one day to find the battery dead and the key in the on position.
I haven't had a chance to take the car out for a test drive as I still need to check the valves and double check the timing but I think my ignition problems are behind me, I hope....
Sounds like I also need to check the compression however and the function of the floats in the carbs. This is not a new carb conversion and according to the previous owner the engine was rebuilt about 10k miles ago.
Hopefully I can find some more time next month to dive deeper into this and I'll try and post what I end up finding.

Thanks for the help guys.

[porschetub]

Originally Posted by Dave at Pelican Parts

Fuel in the oil like that is not so good. It is either caused by dumping way too much fuel into the engine, or not burning the fuel that is going in. Some of the fuel in the chambers can leak past the rings if there is no combustion pressure to help them seal.

Over the long term, you can cause damage to bearings and such, because gasoline is not a very good lubricant. You might also wind up messing up the ring to cylinder wall seal. If the smoke coming out the tailpipe is blue, that is a concern.

Are your ignition woes over? Do you know if your engine is running really really rich?

--DD

time for you and Wayne to put together a carb mod article for the 914,seems a lot of folks are messing up on this one,I personally think its a shame these kits aren't supplied with the ''true'' bolt on parts such as a correct way of regulating fuel pressure and the right pump to use,your thoughts ?

[Dave at Pelican Parts]

To me, carbs are Evil Black Magic (TM). The air goes in, and Mr. Bernoulli waves his magic wand and convinces the fuel to jump into the middle of it. There are tubes and tubes and tubes, some of which are called "jets" (some of which carry fuel, some carry air) and some of which are called "tubes", and then there are fiddly linkage bits to dump extra fuel at the "right" time, and primary thingies and secondary thingies, and oh boy my head is spinning...

So you're not likely to get a carburetor-centric article out of me, at least.

--DD

[TheCabinetmaker]

the fuel pump left running should not have flooded the motor had the fuel pressure been correctly regulated to keep it below the pressure required to overcome the float valve at the correct fuel level in the bowl(s). make sure fuel level is set correctly with the pump running else you may get flooding via the pump left running.


Gasoline does a nice job at cleaning the crank case. one added benefit of a flooded case

[Nostril Cheese]

What kind of carbs are you running?

[porschetub]

Originally Posted by Dave at Pelican Parts

To me, carbs are Evil Black Magic (TM). The air goes in, and Mr. Bernoulli waves his magic wand and convinces the fuel to jump into the middle of it. There are tubes and tubes and tubes, some of which are called "jets" (some of which carry fuel, some carry air) and some of which are called "tubes", and then there are fiddly linkage bits to dump extra fuel at the "right" time, and primary thingies and secondary thingies, and oh boy my head is spinning...

So you're not likely to get a carburetor-centric article out of me, at least.

--DD

Very funny answer Dave ,think its also down to people trading efi for carbs and not knowing that bolt on kit requires a lot of extra work to sort.
One mechanic I knew would get a T4 in and when it ran bad he would say that it must be caused by the fuel injection without proving otherwise.
Many 914's have had fuel injection removed for that reason,shame really as it was a pretty good system.
The right pump and regulator is the key to a good reliable conversion,one motor I have has Weber 36dnva carbs that I setup @ 3.5lbs and was still getting the bowls spilling over ,reset to 3.2lb and problem solved,that how touchy it is.
With a used set it can pay to replace the needle and seats just for piece of mind.

[Tobra]

I think I would probably use a different fuel pump, rather than a reducing valve. Maybe two or three valves in series, backup, so to speak.

Have an old VW with injection that I need to figure out what to do. Getting to where it is tough to find things. Megasquirt? I never messed with anything similar, but am thinking that is the way to go. Wonder if a smog ref would pass that...

[frank]

How does one adjust the pressure in the fuel pump? I don't recall from where I ordered my fuel pump relocation kit, but I don't recall there being any way to set the pressure.

[Dave at Pelican Parts]

One changes the pressure to a carb-friendly one by replacing the high-pressure injection pump with a low-pressure one.

--DD

[frank]

I was asking in an effort to understand the Cap'n's point of view.

I have the rotary fuel pump from CB Performance which provides 3.5 psi.

I don't think it's the pressure from the fuel pump that is causing the leak. I think it's the carb that has the issue. I only have the issue on one side, and I swapped all parts from side to side to determine it's somewhere in the plate that holds the float and needle.

[drifter914]

I had this problem with a '74 Westy, 1.8 engine, dual Solex's, I believe. Turned off the engine for the night... next morning when I checked oil it was about 2 qts over full. I was on a road trip at the time, but knew to always check oil in the morning before starting van. I believe the cause was the driver side carb siphoning fuel during the night. Had same problem again later & finally resolved it by re-building both carbs. May have been a weird combination of things that included a bad needle/seat.