Technical LOTS of fuel in oil pan...!!!

[mightygeorge]

Hi there - been having bad luck lately. i have posted some earlier posts with different problems. The main i am concerned about at the moment is a ridiculous amount of fuel in my oil pan. I thought i could smell some on the dipstick so decided to undo the oil nut so see what's happening. Fuel gassed out in a ridiculous amount. Maybe 1 litre or so of fuel before i decided to cyphen all of the oil through the dipstick with a pneumatic oil extractor.

Let's start from the beginning. Due to a short in the cable from distributor to the coil (it shorted on the exhaust), my coil blew up. It took me a little while to diagnose that. i was cranking the car a few times until i realised i had no spark. i purchased a new twin coil and i now have spark again but the car would still not start. The plugs were always getting drenched in fuel and the the carb was flooding (fuel dripping out).

I was trying to troubleshoot the flood in the normal ways (cleaning plugs, butterfly open overnight and was cranking with pedal to the floor and staying there). Once or twice it tried to start but died soon after. I am kind of glad it didn't as that would have been a bomb waiting to explode.

The engine is a "new" polish one and all ancillaries appear new such as the fuel pump etc. I am trying to figure out what could have caused all these and was hoping to pick your brains.

Could that amount of fuel in the sump be because of excessive unsuccesful cranking? I have a return line and a t-piece returning fuel back to a joint before the fuel pump. The engine seemed well put together and i was hoping it would have new rings...

Could the fuel pump itself be the cause? How do i diagnose a broken diaphragm that could also result in fuel in the sump? Is this a regular occurrence in a new pump???


Any other thoughts?

 

[Franko500]

For fuel to go into the sump:
1. leak from the fuel pump going into sump. this wont cause flooding, only crankcase pressure and ruin oil and possibly damage bearings etc.
2. excessive cranking with no firing - because it is a mechanical pump it will keep squirting fuel into the head everytime you turn it over. It will take a lot to do this. Then the fuel will eventually find its way past the rings and into the sump.


If you had it running before. I would check you have a spark, drain and replace the oil. Possibly change the plugs or burn the fuel off them.
Then give it another go.

 

[mightygeorge]

Thanks sean - tried to clean up sooted plugs with a wire brush, changed oil and fired up again. Nothing for a while. Then it bit for a bit, fired up for a whole 5 seconds and then died again. Retried a couple of times but nothing. I will try some new plugs. Halfords is still open on Xmas eve...!

 

[Vitesse]

I am a bit confused. You say you undid the nut and nearly a litre of fuel drained out. The nut you are referring to is that the sump nut. If so why did you syphon the oil out the dipstick hole and not let it drain out the sump plug?

As Sean says it would seem odd that so much fuel has got past the rings into the sump, you would need to do a huge amount of cranking to archive this and the rings would need to be pretty shot. Where did you get the engine from?

The mostly likely scenario is that the fuel pump is leaking into the sump as Sean says but that is pretty difficult to diagnose from afar. There are two types of pumps, one with screws which you can undo and inspect the diaphragm the other is sealed and you can't do anything with it.

Just read your last post it's highly unlikely that the plugs are shot if they have fired and it ran for a bit, the 500 lump is pretty robust and it will run on one cylinder if one of the plugs is faulty, you would have to be pretty unlucky for both to have failed at the same time.

Tony

 

[mightygeorge]

Hi Tony, the reason for getting the rest of the oil/gas mixture from the dipstick was that it was coming out so quickly out of the sump plug (because it was so diluted) that it was splashing everywhere. I have mototiles on my garage floor and they do not react very well to petrol.

I have one of these little things:

Draper 77057 Manual and Pneumatic Oil Extractor: Amazon.co.uk: DIY & Tools

which makes changing oil (and bleeding brakes) much easier. I also doubt its plug related as i cleaned them well, but thought it was worth a pun.

How long would you leave a flooded carby before trying to fire up again?

 

[Vitesse]

That fact that the carb is flooded is not really the problem, the float will always make sure the correct amount of fuel is in the bowl. The problem is the plugs will have become immersed in fuel, sometimes warming them up with a blow torch will burn off any excess fuel and warm them up a bit which will help.

I would go back to basic before you try again and check the static timing is correct. It does sound like the timing is out if it ran for a bit. Has it ever run properly?

 

[mightygeorge]

Just went back to have another look. Carby seems to have spewed out a lot of fuel in the past hour just on it own (i haven't tried to start it for a 3 hours or so). Fuel all over the floor and tiles all warped... Day is getting better and better. THe only new thing that occurred to me is whether this could happen because the car is at a bit of an angle? The front is slightly raised (maybe around 7-10 degrees or so as it had been on a ramp...

 

[mightygeorge]

Hi again Tony - yes it run beautifully at the beginning on idle for a couple of days and it pulled nice and strong when i took it out for a short spin a couple of days ago. It was during that trip that the Coil was damaged due to a short and i have been struggling ever since to get it back to work... I also wonder whether there may be a vapor lock or something?

 

[Vitesse]

Hmmm I think you might be going off on a bit of a tangent with the vapour lock idea.

So going back to the start you had a 500 with a 500 engine, obtained a 126 650 engine wanted to fit that, and looking at past posts you fitted an accuspark as well. What type of coil did you use originally on the new 650 engine that ran ok before it blew up? Was it the original 500 one? Because I think I read you had now fitted a twin coil? What makes you come to the conclusion that that coil burnt out and leaked oil because of a short of the LT wire on the exhaust.

I am not doubting anything you say, just trying to get a clearer picture of the history.

Tony

 

[Franko500]

Just thinking it could be your pump but why its started now could just be a coincidence.
The pump has a diaphragm that if perishes would allow fuel to go straight into the sump. This would cause back pressure behind the pistons and possible prevent engine from running. This would then lead to possible flooding.
It may well be worth checking if you have the type with the screws around the top..

 

[mightygeorge]

Vitesse Thanks so much for taking the time to look into this. Yes started off with a 500 with a 500 engine, it had a full resto down to bare metal and lots and lots of new panels and paint. Through pure greed and bad planning I ended up acquiring not one but 2 650 engines and boxes (the one that had the powerspark unit has now been sold) to a chap from Surrey that has 3 fiat 500s. That one had a single ballast coil, this new engine I have now (supposedly never run before - http://www.ebay.co.uk/itm/131658659524?_trksid=p2057872.m2749.l2649&ssPageName=STRK:MEBIDX:IT )came with a double oil filled coil. When than went kaput I could not find a similar one to replace it and got a dry one. In any case spark is no longer the issue as i have a spark tester running just before the plugs and that produces a nice crisp spark. The current issue therefore (leaking fuel and flooding) must be carb/fuel pump related. It just seems bizarre that it all started after the coil went as before that the car was starting on the button every time and running really well. Hope that's cleared it up a bit?
Franko500 - thanks very much for that diagram. My pump has got the screws so i will try to dissect it tomorrow. The sump has got lots of petrol in it again only after 2 attempts to restart the car. I can smell it on the dipstick and it actually lights up very quickly with a naked flame.

 

[portland_bill]

Just went back to have another look. Carby seems to have spewed out a lot of fuel in the past hour just on it own (i haven't tried to start it for a 3 hours or so). Fuel all over the floor and tiles all warped... Day is getting better and better. THe only new thing that occurred to me is whether this could happen because the car is at a bit of an angle? The front is slightly raised (maybe around 7-10 degrees or so as it had been on a ramp...

If the carb is flooding, the float valve is sticking open. Get the lid off and clean it. It will flood directly into the manifold, and if the engine has been stored a while, the rings may not seal perfectly, so the fuel will drain to the sump.

 

[Vitesse]

Oh right thanks that clears it up.

I would imagine that the diaphragm has split inside the fuel pump. As it's never been run and sat for donkeys years it is probably perished.

 

[Paolo66]

I would guess at a split diaphram George. This should become obvious once you strip it down. I have a spare one if you get stuck
Damian

 

[dunnah01]

How have you plumbed in the fuel return for the 650 engine? - the 500 didn't have one so may be some extra fuel pressure finding the weakest route through the carb float valve

 

[varesecrazy]

Yes started off with a 500 with a 500 engine, The current issue therefore (leaking fuel and flooding) must be carb/fuel pump related. It just seems bizarre that it all started after the coil went as before that the car was starting on the button every time and running really well. Hope that's cleared it up a bit?
Franko500 - thanks very much for that diagram. My pump has got the screws so i will try to dissect it tomorrow. The sump has got lots of petrol in it again only after 2 attempts to restart the car. I can smell it on the dipstick and it actually lights up very quickly with a naked flame.

Hi,
( not knowing quite what you have / NOT got fitted, )

your oil is definitely being contaminated directly by fuel..NOT just by unburn cranking fuel,

a flooding carb is fairly obvious - the problem lies in what powers the carbs fuel supply..,

is it gravity fed, vac fed,

powered from the motor spinning,

OR ( my suspicion) electrically powered, and your change of coil electrics means it's powered above it's normal level.


the fact it barely runs also points to the carb flooding, as the cylinders are seeing unmetered fuel ( by-passing jets)

Charlie

 

[mightygeorge]

I really am at a loss with this guys. I have taken Paolo66 Vitesse and franco500 advice and pulled the petrol pump apart. There are no splits in either of the 2 diaphragms. Air flows only from inlet to outlet and not the other way round. Pulled it out of the engine with the lines still connected overnight but no fuel came out of it.

I then took out the carburettor cover as suggested by portland_bill to see if the float was getting stuck. The valve seems to go up and down freely, i cleaned it up in any case and put it back.

I cleaned up the plugs again, replaced the oil (again) and hoped for a Xmas miracle. Turned the engine over 3 times for about 5-10 seconds each time. Result? Flooded carburettor, fuel dripping out of the tray, brand new oil smells of fuel again and a car that didn't start. Tried with the choke on initially and then off - no difference.

Any new thoughts?? I have spend the past few days stinking off fuel... urghh...
varesecrazy running a very simple mechanical pump. not an electric one. I wonder if it "oversupplies" fuel? I haven't run a fuel pressure gauge to check what psi the output is yet.
dunnah01 Yes i have plugged in the return and connected it with a t-piece to the line running from the tank, before the pump. I thought maybe i will block it off but that surely would only makes things worse? I presume that the output from the carb only allows for one way flow? If not there was a possibility that originally fuel was actually flowing in there from the tank as the car was parked in an incline. The car is now level and that made no difference.

 

[Paolo66]

Next time you take the carb apart George, take the float out and give it a shake. The floats can get a small crack in them and then fill with fuel. This then causes flooding
Damian

 

[dunnah01]

You could try cranking the engine with the top of the carb removed and the float taped closed to see if there is any leakage.

 

[portland_bill]

You could try cranking the engine with the top of the carb removed and the float taped closed to see if there is any leakage.

This is a good idea.

The carb is flooding.
This is caused when the float valve allows more fuel through than it should. Usual reason is a worn float valve, but this can also be caused by excess pressure.

This is a change of engine, from a 500 to a 650. presumably you are now using the 650 carb and 650 pump, which should be matched. If you are using the 500 carb, with the 650 pump, it could be delivering more pressure that the 500 float valve was intended to cope with. So check the valve actually is capable of stopping the supply, with the top off, you can hold it to establish this. You holding it will be much tighter than the float will exert.

Now we'd need to know what the pump output pressure is supposed to be, compared with the 500. However, if you are using the 500 carb, unless you've rejetted it to suit the 650 engine it will not run well, and may lead to other issues once not flooding. You really do not want a weak mixture, as this can hole pistons.