10 replies to this topic

[Edmonds87]

Having had numerous troubles with fueling my newly built engine, I have now discovered fuel in the oil. My guess being its been leaking past the diaphragm of the fuel pump (which would explain the fueling issues)

Having now drained it all out (aprox 7-8 litres of liquid came out of the sump) there will surely be a film of oily fuel lining the inside of the engine!? how would i go about flushing the engine to ensure i get rid of all the C**p?

Also is it likely to have done much damage to the internals of the engine? I don't have a clue how long the fuels been getting ito the oil. I only notices it as it was leaking from one of the breathers a few days ago. I never had the chance to run it on the road but have run the engine with the car stationary for approx 1.5 hrs in total since rebuilding it!

[jonny d]

I Had the same thing happen to my mini the oil/petro also got past the crank seal and onto the clutch plate ALL I did was give it 2 oil changes
1st one cheap oil drove the car with slipping clutch got oil hot then drained it out and then put the dear oil in clutch seemed to cure itself after
awhile aswell took clutch apart 1 year later not a pretty sight in there at all.

[Big_Adam]

Leave the sump plug off and the rocker cover off.

Fuel "should" evaporate naturally.

...I think.

[Dan]

Firstly, for anyone reading this with similar problems DO NOT run the engine or especially drive a Mini (or any car for that matter) once you have discovered fuel in the oil. There is a very real risk of an explosion in the gearbox in the case of a Mini or the sump in other cars. Yes this will be every bit as serious as it sounds.

You are probably right about the fuel pump diaphragm being the cause, it's the most likely thing.

Since you have removed the majority of the fuel by dropping the oil you have reduced a lot of the risk. Do as Adam says and let it ventilate overnight (rocker box off entirely, not just the cap and pull the emissions hoses off the breathers) for safety if you are worried. Obviously don't now let it fill with rain water! Reassemble, change the filter too and fill it with cheap oil and a can of oil flush. Run it for 15 minutes and change it again (oil and filter) for some proper oil.

There could be damage due to oil being washed out of the bearings or off the cylinders but there is no way to tell without stripping it down. Treat it carefully for a while (it is still running in anyhow) and see how it goes would be my advice. It has only been running for a short time but damage to bearings can happen in just minutes if the oil is seriously diluted. I would say run it in like normal and see how it goes.

Oh yeah, and get a new fuel pump!

And incidentally it is not good for a newly built, running in engine to sit and idle or run with no load for any length of time. You will prevent the rings from bedding in properly if you allow the cylinders to glaze. Run it in properly and it will last a long time. Don't and it won't.

Edited by Dan, 23 June 2007 - 07:27 PM.

[Jupitus]

And incidentally it is not good for a newly built, running in engine to sit and idle or run with no load for any length of time. You will prevent the rings from bedding in properly if you allow the cylinders to glaze. Run it in properly and it will last a long time. Don't and it won't.

Hey Dan - would you care to elaborate a little more on this? I remember years ago I ran an engine in overnight in preparation for a rally by driving at a steady 40 or so for about 400 miles, without revving it or loading it too much at any point, i.e. just gentle driving. What advice have you got?

[Dan]

Sounds like that was an ideal way to run in an engine, light normal everyday load at lowish revs. Driving up shallow hills and the like at about 40 is perfect IMHO. However idling or sitting without driving and having no load or going too fast with too much load is bad. What you are trying to do is lap the components into each other, the rings need to key the cylinder walls and all the various mating surfaces need to grind into each other. If you were hand lapping something and you did it without putting any force against the component then it would never grind and the surface would just glaze over. If you leant on it too hard or for too long you'd wear away too much and shorten the life of the part. You have to get it just right and you do it by feel once you've got used to it. That's what I compare running in to in my mind. Maybe it's not right but that's how I see it.

Edited by Dan, 23 June 2007 - 09:30 PM.

[Edmonds87]

Thanks for all the replies so far!

Having taken the suspect fuel pump off today ive found no visible damage to the diaphragm on the pump. I blew through the inlet of the pump whilst pluging up the outlet before taking the pump apart and there were no leaks whilst doing this.

Are there any other places the fuel could be getting in? apart from the pump if the pump is not the cause?

[jonny d]

I still suspect the pump just put a new one on and it will probably be fine, blowing through it is not a indepth test really

[Edmonds87]

I still suspect the pump just put a new one on and it will probably be fine, blowing through it is not a indepth test really

Ok thanks jonny just wanted to cover my a*** as the list of bits ive bought before, during and after the rebuild of this damn engine to try and get it working properly is never ending! There's always something going wrong which needs fixing! AAHHHHHHHH! And it doesnt help that im now without a job and overdrawn!

Y DO WE BOTHER????

[Grayedout]

You say it's a newly built engine ? Have you set it to run lean ? If not then it may have have been over fuelling and washing the bores with fuel and dropping into the sump !!

How is the oil consumption ? How many miles have you done ?

[Edmonds87]

Only had the chance to run the engine 4 about 15 miles max as it has been runnin like a pile of s*** since the re-build. Ive replaced numerous part to try to get it to run better but with no luck. So havent had the opportunity to run the engine 4 long enough to determine the oil consumption. However it has maintained the same level through the time i have had it running.
Wasn't until the other day that i read up about the charcoal canister usually placed in the front passenger wheel arch. This i never re-fitted after the rebuild. I didn't want it pumbed in as wanted the breathers fitted with breather filters insted of the evaporative emmisions control system so ran the fuel return from the carb overflow directly from the fuel return to the tank, vented the two breather to fresh air with filters and connected the vacuum pipe from the carb directly to the vacuum advance on the distributor thus allowing me to remove the canister. However i have read that without it connected it can cause staring and running problems so decided to refit it.
It was only after refitting this that i started the car to find that it chucked out a load of white smoke out the exhaust once it started and then cut out. Was after this i discovered the fuel in the oil. Could it be that ive reconnected it wrong? Would this cause fuel to be pumped into the sump? Perhaps through the breather pipes?