Who dumped the gas in my oil?

Runnin 44 Webers on a 2110. Fire it up this AM and it blumps and sputs a little worse than normal on cold start but it settles down. Driving to work and the oil pressure is moving around (doesn't normally). Idle is ok but run 2 - 3k is like 5 lbs or so low. As temp goes up it shows ~10lbs lo at 2k. Get to work check oil and the good fairy put and extra qt. in the as it has too much. My theory is that, it has a full tank and it apparently has developed a "leaky" main metering valve in a Weber allowing the gas tank to drain to the crankcase whilst it's sitting. Runs and drives fine. Does that sound like a resonable assumption or did I miss something?

If you have a VW mechanical fuel pump the diaphram is probably cracked or holed and is leaking fuel into the sump.

Should have included that George. I'm running elec pump only.

I had a 911 years ago - had carbs rebuilt professionally and not thinking I installed them without thinking to check how the accelerator pump linkage was adjusted. Every time I hit the gas even just a little they shot extra gass in. Car ran fine till the dry oil sump filled up with the extra gas and leaked onto hot exhaust heat exchangers causing a small fire at a toll plaza (fortunately with a fire extinguisher). Towed it and drained the oil --- engine sure was clean inside after that! Could have been worse - was fire engine red and I had not road insurance on it at the time. I sold car soon after - but always wondered the consequences of diluted oil on the rings/bearings and the CO2 chemicals on the engine case!

Bill,

Crack the drain plug on the strainer plate just a tick and see what drains out. The gas should be heavier than oil so if you've contaminated the crankcase, gas would drip out past the drain plug threads. Of course, you would also be able to smell the fuel as well.

Luck,

TC

"Gas is heavier than oil"??? Well I never thought that.....hmmmm...

Bill wrote: "My theory is that, it has a full tank and it apparently has developed a "leaky" main metering valve in a Weber allowing the gas tank to drain to the crankcase whilst it's sitting. Runs and drives fine. Does that sound like a resonable assumption or did I miss something?"

Yup, that's the first thing I thought of, too.

Let us know what you find.

gn

AH-HA, so i am not alone with a gas-in-the-oil story. In my first "incident" I somehow increaed the pressure in the crankcase sufficiently to raise the dipstick and spray oil all over EVERYTHING in the engine compartmant. I never did find a cause for that! Engine had all required breather tubes running to both Weber 44s. No blockage anywhere. Changed the oil and luckily, no physical damage seems to have been inqured (my psyche was not doing so well though).

Second incident, short time later, was definitely the result of gas leaking past the carb, directly into #4 cylinder with the engine OFF. This time I pulled #4 sparkplug and found #4 cylinder COMPLETELY FILLED WITH GAS! I siphoned the gas off the piston, changed oil, and the engine fired right up and ran fine.

My Weber guru has since dramatically reduced the leakage, but it still occurs, though at a much reduced level. The evidence is a "wet" gasket between carb and manifold. The gas drops from the venturi tubes, onto the butterfly where gas collects and soaks the gasket.

My temp solution was a mechanical shutoff valve in the engine compartment. That did stop the problem, but it's a bandaid. Still chasing a permanent solution. Confident will be solved before Knott's. The vehicle performance never changed throughout.

Oh, I forgot to add . . .

If there IS an amount of gas in the oil, if ANY drains from the crankcase at all. Don't start the engine until you drain and refill with fresh oil AND solve the problem.

The oil pick-up tube is going to be sucking up the fuel before it sucks up any oil and you'll end up washing down and spinning your bearings. Might wreck your crank . . . no biggie if it's just a stocker, but otherwise, a big pain in your wallet.

Just a thought that I forgot.

TC

david, as for a fix for a leaky carb, it could be a couple of things with in the carb,
float height, float needle or ball condition (sticky, damaged, dirty).
the float raises up closing off the fuel flow just like a toilet tank. for one reason or another
the fuel bowl is dripping into the carb throat, float drops and refills the bowl.
another reason for the fuel "overflow" if you will is heat soak/expansion.
fill a antifreeze bottle half way with fuel and leave it in the sun, the bottle expands like crazy. same with your bowl, expansion, drips, float drops, refills.......

Got to say, it's happened to me. Sound like a pretty common problem. Happened to me a few times in the past with Webber ICT's, mine leaked on the other side and filled #1. As a reference, I use a facet pump?

Never really cured it, but now have new (rebuilt) carbs and hope its gone?

Boston Bob E.

Been a while since I worked on Webers.

Can someone tell me if the float needle valve has a rubber seat or a metal one? Older Rochesters had a metal to metal seal which, if you ever got any water in the gas, would corrode and have to be re-faced. There was a special tool for it, but it only took a few seconds and you were done. Couldn't be done on the car, though, as you had to flush out the grindings before re-installing.

Lots of other manufacturers saw this problem and provided for a rubber seal (which wore out quicker - you can't win!)

gn

Gordon
I'm thinkin they're metal, but it's been awhile (or I wasn't paying attention). Probably won't get it torn apart till late in the week.

Seems odd, you mentioned water in gas problems...Put hi test Shell in it and that's when the crap started. Plugged idle jets repeatedly, as in immediately, and then it starts relieving itself in its oil pan. Could be coincindence.

Will let you know

My wife says I go nuts when I pull in to a gas station and there's a tanker there filling the ground tanks. I absolutely WILL NOT, under any circumstances, get gas at that station.

When the new gas flows into the underground tanks it stirs up all sorts of crap that finds its' way into YOUR tank when you fill up. It can take several HOURS for all that stuff to settle, sometimes longer, and everyone getting gas there during that period is filling up with that stuff - some of it even gets through those fancy nozzle/hose filters (if the filter cartridges are even installed, which, more often than not, they're missing).

I've seen that stuff clog a brand-new gas filter in a matter of minutes, such that the engine wouldn't run above an idle. I've also opened up carbs after an incident like this and seen almost a quarter of an inch of silt in the bottom of the bowl. All you can do is take them apart, do a rebuild and put'em back together - that usually cures them.

OH!! REALLY IMPORTANT!!! Change your fuel filter(s), too! I have two: A canister just before the electric fuel pump up front, and an in-line just before the carbs out back. Just looked at that one the other day (it's clear) and the element has gone from beige to dark gray in one season.

Gordon

I'm told that gas shutof needle/seat come with either a metal seat (orginal) or with a viton seat (aftermarket). Viton seems to be preferred after 50 years of progress.