FUEL IN ENGINE OIL

[GBWAUGHM]

Dear Forum,

I have just had my S3 engine rebuilt after a bottom end failure. The engine sounds great however on draining the oil the garage believes there is fuel getting into the oil. They have drained the oil 3 times now and while getting better there is still a smell of fuel. A sample has been sent of for testing. Carbs had all seals replaced and no leaks here. Any guidance welcome please.

Thanks

[J44EAG]

Defective seal on a mechanical engine driven lift pump?

See this thread. Although for a diesel engine, this little tale might be a pointer. viewtopic.php?f=10&t=11650

Many years ago I witnessed my Fathers brand new Triumph 2000 suffer a pump leak into the sump having covered just 42 miles. That allowed fuel to enter the engine block and dilute the engine oil. Has your engine been fitted with a new lift pump as part of the rebuild? Dilutred fuel will in a short time lead to bearing failure.

Mike K

[oldtimer]

Hi,
Although not immediately obvious from your thread, it appears you have a Series 3 E type with V12 engine.
Fortunately you do not have a mechanical fuel pump attached to the engine.

The V12 engine is fitted with four Zenith Stromberg Carburettors.

Question ---- How is petrol getting into sump ??
This engine is fitted with a manual choke which enriches the fuel flow on the front right hand carb and the rear left hand carb. With full choke selected it is like firing a fire hose up a side street. Under this running condition the car cannot be left to idle cos it will choke it's self to death due to the excessive fuel flow and come to a stand still. Then trying to restart can be an absolute night mare.

In my experience if the car is backed out of the garage on a daily basis while the garage space is used for some other purpose each time a start up takes place a little more surplus fuel washes the bores and ends up in the sump. Over not a considerable time you can watch the oil level climb up the dip stick. My Pal around the corner with an Aston Martin who owns the village garage does exactly the same and complains about oil level increase.

So you may not have a problem at all that an Italian Tune up would not cure. A jolly good thrash up the road to evaporate off the petrol.
Avoid repetitive start stop.

Next ---- Remove all four carb dashpots ensuring they are not inter changed and the air intake manifold.
Switch on the ignition and check the fuel level and ensure it is not flooding , light tap with a handle of a screwdriver can often settle things down. When refitting the dash pots rotate 10-15 degrees in both direction to ensure they are well seated and when screwed down lift the piston and ensure it snaps down onto the bridge. Oh, by the way while the dash pots are off examine the rubber diaphragms for splits and ensure the tongue locates into it's recess.

I think that will do for starters --- come back if you need more

[GBWAUGHM]

Thank you all for your input. I will let you know how we get on.

Regards