Lotus Elan and Lotus Elan Plus 2 Forums

I previously asked about massive blow by on a new engine. Well at some point I thought it may have too much oil and was having a very hard time seeing the level on the dip stick. I decided to drain the oil, refill and see. When I removed the oil plug I must have drained 8-10 qts of oil/gas mixture! The question is, did it come from a leaking diaphram(sp) or are the carbs pouring gas and washing down cylinders. I think the fuel pump is the problem because the car ran ok. Remember it is a new engine and has only been run in my garage about 4 times. Where to start?
Thanks,
Brian

Brian,
I think it's much more likely it's a bad fuel pump diaphram - a mixture that rich would foul plugs in minutes. I had a similar problem with a diesel boat motor - fuel accumulated very quickly in the oil, forcing me to change oil every hour while underway, while delivering the boat on a 500-mile journey.
Good luck,
Greg Tatarian
1971 Elan S4 DHC

Brian: For the love of God, please... DO NOT RUN THE CAR UNTIL YOU CHANGE THE GAS PUMP!

Gas in the oil may cause a lot of damage in a short period of time! Change the pump ASAP.

You may want to consider an electric gas pump. The problem with the new aftermarket mechanical pumps (made in India) is that they put a pressure of about 5 psi. So you need a regulator. I got tired of the aftermarket pumps and decided to buy and install an electric pump (I deleted the mechanical one).

Best

Carlos

Brian,

I agree with Greg that it is most likely the fuel pump.

Carlos,

If the fuel did some damage, I would think that it would damage the rings and bearings before it would damage the oil pump. Please tell us why you think that it is crucial that Brian should replace his oil pump. Thanks.

I meant to say "gas pump." A typical case of age related "lapsus scriptus"

The gas pump must be leaking and leaking badly. Gas in the oil acts as a thinner and ... you can imagine "the horror, the horror"

My Sprint with Webbers quickly deposited a large amount of fuel in the oil when one of the twin floats punctured. the other float was just enough to keep the motor running and ran clean after about half throttle. Did not apear to flood carb but was very rich on two cylinders.

I decided that the problem had to be the fuel pump due to the large amount of fuel in the pan and the fact that the car started and ran ok. So I jacked up the front end thinking I would remove the starter and get to the fuel pump, but it appeared that I should also remove the rear carb, which I did. I took off the two fuel lines from the pump and was ready to start removing the starter when I noticed that the fuel bowl was almost full of gas. I thought it would be empty if the diaphram was leaking back into the block..... What am I missing? Also wondering if I should replace mechanical pump or install an electric one in the trunk/boot? Can it be piped with the fuel tank in place? Is there a wiring issue?
Thanks,
Brian

Brian,

Just because the bowl is full of gas doesn't mean the the pump isn't pumping gas into the sump as well. No need to remove the starter but push yourself away from the computer, take the pump off and have a look.

It must be the fuel pump.

You can install an electric fuel pump in the trunk or under the car ( as I did). I can take a picture for you.

So I got away from the computer and removed the old(new) glass top fuel pump and installed another new one without the bowl. Was careful not to cross thread anything and tightened all fuel lines. Car started, great oil pressure, no blow by, and no fuel in the sump...that I know of. Very discouraging to find a fuel leak at the suction side of pump. The last piece of the fuel line is alum. tube with a brass fitting and a bubble/double flair end. There was no compression olive used on the old pump so I just ASSumed I did not need one. Do I need to redo this and add a compression olive or what? I also opened the fuel filler and discovered that it was under negative pressure. Do I need to drill the little plate or the inside of the rubber gasket? This is getting old!
Thanks,
Brian

Brian,

I had a pesky fuel leak near my pump outlet that I couldn't seem to eliminate regardless as to how hard I tightened the nut that held the metal line on. Eventually, I cut off the double flair and picked up a compression olive at my local hardware store. Once this was installed, my fuel leak disappeared permanently.

Don't you have to have some sort of flair to keep the threaded fitting on the pipe? Did you just put the olive at the end of the tube? I am missing something......

Brian,

The threaded fitting goes on the pipe first. Then slide the olive over the end of the pipe. Push it up the pipe so that maybe 1/4" of pipe is showing behind the olive. When you screw in the threaded fitting into the fuel pump, it will compress the olive which will make the olive grip the pipe and prevent the pipe from slipping out.

Sorry but I have to ask - what is a compression olive???

The fuel pump was the problem, The leak at the suction side was easy to fix and the car seems to run great. I now need to get it finished so I can road test it. I know, "get away from the computer" and finish it!

Still questioning the negative pressure in the fuel tank. I thought it would vent thru the center of the cap. Can anyone enlighten me?
Brian