gas in oil
 

My 1960 with 2x4's is apparently diluting the oil with gas. The dip stick indicates higher rather than lower levels over time. I don't smell a strong gas smell in the oil, but something is happening. I pulled the plugs and they are burning clean (white/tan color)and it does not emit black smoke. So I'm left with two possibilities (a) the fuel pump, new last summer, is leaking into the crankcase or (b) the carbs are thinning the oil. My problem is that I don't a test for either issue. Any suggestion son how to track down the problem?

First thing to check is the fuel pump - if that diaphragm blows its bad news....don't drive the car until you sort it out. Diluted oil can result in galled cylinder walls.. Carbs shouldn't be putting raw gas into the crankcase, rich running carbs would definitely result in black exhaust and crusty plugs.

If your carbs were rich enough to dilute the oil I think the car would barely move...

Check the fuel pump at the vent hole and see if it is blowing oil vapor out. If it is, I'd change the pump.

You should have any gasoline odor in the crankcase. Not even a little.

Thank you both Frankie and Mike - I will check the vent hole on the pump. I do not see any sign of oil in water or vice versa. Pump is my guess.
I'll get back to report results.

Leaking fuel pump diaphragms in GM fuel pumps have been a problem for many years letting gasoline get into the crankcase noticeable by heavy white smoke coming from the exhaust and it can destroy an engine in minutes if you continue to run it . Change the fuel pump and oil and filter . And if it's a valuable engine and not just a driver/beater change it again soon after .

I borrowed my nephew's Pontiac in 1969 for a 52 mile drive home. When I let off the gas for my exit I heard a bomb go off and a flash.
I blew the pan and valve covers. They stayed with the engine by a few bolts.
Another was in high school when (of all teachers) the auto shop teacher asked me to check out his 6 cylinder Chevy oil problem. His problem (he said) was that he does not see oil on the dip stick and already added more oil than the engine should have. He didn't see the clear gas diluted oil because it was at the top of the stick and he was looking at the bottom of the stick at the add mark.
Back to the Pontiac, Don't know what ignited the fuel in the crank case but blew 2 clutch covers, 1 at a time, on a old British bike before I figured out there was gas seeping past the gasket due to the priming method done to start the engine. The carb was above the cover and when priming, which held down the float long enough to see fuel come out of a drain hole, allowed the gas to seep in the cover where the coils for the generating system were.
On the other hand, they intentionally diluted aircraft oil in cold temp airports so they could get oil flow with the thick 60 wt oil. The book required a time period that would allow the gas to evaporate out of the oil. What were they thinking. More modern fuel pumps have a 3rd diaphragm installed to catch fuel and dump it thru a tube in the event the main diaphragm fails. That fuel pump will fit a Chevy at about 20 times the cost.

Dom

How does gas getting into the oil cause white smoke? I completely agree with you on the fuel pump and not running the engine until the problem is fixed.

Have never seen gas in oil cause white smoke. Ever. Have seen blue smoke from engines worn out by running gas-diluted oil over time. The blue smoke is oil burning due to worn piston rings and cylinder walls. The only cause I've seen for white smoke is a blown head gasket or other internal coolant leak. YMMV...........

We used to get engines in the assembly plant that had gasoline in the crankcase. Sometimes, two/three quarts over full. This went on over a period of a month or so. I could only speculate the cause. The odor of gasoline on the dipstick was very strong.

Never had a crank case explosion but these engines wouldn't pass the inline process of passing the emmision test at the dyno roll test. We changed the oil, they passed and went on their merry way.

My BIL had a 69 Vette with a 327 in it. It used to use a qt of oil every1000 mi or so. One day he me told it stopped using oil. Hmmm I said. A short time later you could use the car for insect control !! Ruined the engine. Fix it NOW !!!

Back in the seventies I have seen several chevy engines with failing fuel pumps fail and the gasoline thins the oil and then it is the oil that burns causing the white smoke . I personally had and old 350 truck engine do it .

When high concentrations of gasoline gets in the crankcase oil, I've seen the white vapor come out of the oil filler tube. Didn't notice the tailpipe.

Mike et al.

So, I didn't find trouble with head gasket etc. but decided it was a good idea to install an electric FP. I changed oil and filter and after examining the oil not so sure I really had a problem gas problem, may be just over reacted. . Anyway, I bought a Mr. Gasket elec. FP and did the install. All appeared to be okay, and the car started right up and ran great. But, when I turn on any elec. power such as brake lights, headlights, radio, the fuel gauge moves to F. Seemed like a ground issue, so I tried running a ground to various places such as bolt on the fuel pump cover and then valve cover screw, just to see if this solved my problem. It didn't. Any suggestions.?

I would need to see how you powered the electric fuel pump... It should go through a switched (via ignition switch) source of power and I assume its an external pump placed near the gas tank... You have to be extremely careful in the selection of an electric pump for carbs - nearly 4 out of 5 I looked at had excessive pressure for carbs. Mine has about 4-1/2 to 5-1/2 lbs which is spot on... My gas gauge works perfectly.



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