gas in oil: from leaking carburetor(s) or past rings?

[jtauxe]

I am refurbishing an essentially all-original 1972 Sportsmobile, with its original 1700 engine and carb setup, to boot.

This bus has sat for a long time -- probably did not move for 20 years. Colin and I got it fired up at the end of last summer, and I had not done much with it over the winter, but spring is here, and my goal is to bring it to a level that we could make the August trip to southwest Colorado for the bus bomb trip up from Durango.

Done before/with Colin:
- new fuel lines
- oil and filter change
- valve adjustment
- cleaned out air cleaner (cool 1972 oil bath bucket type)
- basic timing adjustment

At that time, the bus ran, held idle, but seemed sort of gutless. We did the remove-the-spark-plug-wire-at-the-rotor-for-each-cylinder-to-see-if-it-is-contributing trick, and decided that a couple of cylinders were not contributing. Fresh spark plugs and wires might do the trick, but we were out of time.

Done this spring:
- new spark plugs and wires (old plugs were black and sooty)
- replaced several cracked vacuum elbows
- fresh gas

It drives about the same, and I can definitely say that cylinders 2 and 4 are doing all the work, while 1 and 3 are doing nothing.

Then I had a thought: I should not drive this much if these cylinders are not firing, because that is just squirting gas into the cylinders and it might damage them -- certainly the oil would be made less effective.

So I go to sniff the oil dipstick. Ah - definitely gasoline. This does not make a good lubricant.

Now I am wondering - Is the gas in the oil due to gasoline introduced into and not burned win the 2 dead cylinders, or could it be from a leaking carburetor? How could I tell?

Note that it is one cylinder on each side that is dead, so this does not point to just one carb or the other needing attention.

So, I'm looking for another test to fix the gas-in-oil situation, so that I can change the oil and not have to worry about more getting in there. So, I would like to pose a couple of questions:

1. Would the amount of gasoline mixing into the oil from non-firing cylinders amount to enough that I could smell it in the crankcase oil?

2. Is there a simple test to see if the carburetors are leaking? I was thinking:

A. See if the oil level is rising with time with the bus sitting still, and
B. unbolt the cylinder [edit] carburetor and set it on a piece of cardboard or something (still in place), and see if it is draining gas through the bottom.

All constructive thoughts appreciated!
_________________
John
"Travelling in a fried-out Kombi, on a hippie trail, head full of zombie..." - Colin Hay and Ron Strykert
http://vw.tauxe.net
1969 Transporter, 1971 Westfalia, 1976, 1977, 1976, 1977, 1971, 1973, 1977 Westfalias,
1979 Champagne Sunroof, 1974 Westfalia Automatic, 1979 Transporter, 1972 Sportsmobile, 1973 Transporter Wild Westerner, 1974 Westfalia parts bus, 1975 Mexican single cab *FOR SALE*, 1978 Irish 4-door double cab RHD

[aeromech]

B. unbolt the cylinder and set it on a piece of cardboard or something (still in place), and see if it is draining gas through the bottom.

I think you mean carburetor. Might work if you leave it hooked up to the fuel line. It's the head pressure from the tank that overcomes the carburetor needle valve.

Have you tried doing a compression test?
_________________
Lead Mechanic: San Diego Air and Space Museum
Licensed Airframe and Powerplant Mechanic
Licensed Pilot (Single engine Land)
Boeing 727,737-200-300-400,757,767
Airbus A319,320,321
DC9/MD80
BAe146
Fokker F28/F100
VW type 1 1962,63,65,69,72
VW Type 2 1971 (3 ea.) 1978, 1969
VW Jetta
VW Passat
Capable of leaping tall buildings in a single bound

[TDCTDI]

More than likely it's from a ruptured diaphragm in the fuel pump. The fuel will then continue to drip into the crank case, when it gets full enough, it will seep past the rings & foul the plugs upon start up.
_________________
Everybody born before 1975 has a story, good, bad, or indifferent, about a VW.


GOFUNDYOURSELF, quit asking everyone to do it for you!


An air cooled VW will make you a hoarder.


Do something, anything, to your project every day, and you will eventually complete it.

[Wildthings]

Twenty plus year old carbs need to be kitted, period. Even if they weren't giving problems today they might very likely fail tomorrow. You don't need either a bus fire or a seized engine.

[airschooled]

My friend had an issue with his factory dual carb bus dripping with the original carbs; he didn't drive it often either.

Here is a video of the fuel dump after shutting down the engine. Hopefully yours isn't this bad:


Link

_________________
Learn how your vintage VW works. And why it doesn't!
One-on-one tech help for your Volkswagen:
www.airschooled.com

[jtauxe]

[jtauxe]

Any thoughts from folks on how to evaluate the health of the original fuel pump?
_________________
John
"Travelling in a fried-out Kombi, on a hippie trail, head full of zombie..." - Colin Hay and Ron Strykert
http://vw.tauxe.net
1969 Transporter, 1971 Westfalia, 1976, 1977, 1976, 1977, 1971, 1973, 1977 Westfalias,
1979 Champagne Sunroof, 1974 Westfalia Automatic, 1979 Transporter, 1972 Sportsmobile, 1973 Transporter Wild Westerner, 1974 Westfalia parts bus, 1975 Mexican single cab *FOR SALE*, 1978 Irish 4-door double cab RHD

[wihr]

I had the same problem when I used to park nose high on a relatively steep hill. I would leave my bus for a few weeks and would find the oil reeking of gasoline. I never solved the problem, but I am sure it was the carburetor. I do not live on a hill now and park my bus in a garage. No problems.

WW
_________________
WIHR

1970 Campmobile "Van Ordinaire"
2009 Lincoln Town Car "Behemoth"
1969 Lambretta 150 DL "Nina"
1962 Matchless G 12 CS 650cc