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Author Topic: Diesel in sump  (Read 401 times)

ygododdin

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Diesel in sump
« on: March 17, 2020, 07:31:30 PM »
Hi.
I have a Lister STW three cylinder engine which is leaking diesel into the sump (the oil level is rising, albeit slowly).
I don't know if there's a leak in the fuel system or it's caused by glazed cylinders.
I don't feel confident enough to deal with it myself, so is there a lister expert in the Banbury, Daventry, Coventy area who could help please?
Many thanks.

listard-jp2

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Re: Diesel in sump
« Reply #1 on: March 17, 2020, 08:13:33 PM »
This is something you could look at the easy fixes yourself, and get an expert involved if they do not fix the problem.

The sequence of leak checking is as follows (easy to hard)

Does the engine have a lift pump, if so take a look at the lift pump diaphragm as these do fail quite frequently

Take off the rocker covers, and check the tightness of the the injector cap nuts

Take off the injector clamp bridges, and check the rubber bung in the injector cap nuts is not leaking (they tend to break up over time)

Take a look at the leak off pipe and fittings, as they will now be accessible.

Remove the injection pump inspection door, and check tightness of banjo bolts on fuel inlet to each fuel pump

Check tightness of fuel pump bleed screws

Check tightness of delivery valve holders on each fuel pump

Replace Dowty washers on injector pump banjo bolts

If the leak still persists after all of the above, then your into fuel pump strip down territory (not difficult if you know what your doing).


 

mike90045

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Re: Diesel in sump
« Reply #2 on: March 18, 2020, 02:32:36 AM »
I'd think if it was blowing by the rings in the cylinders, you'd be getting lots of gunk visible in the exhaust.

scott p

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Re: Diesel in sump
« Reply #3 on: April 27, 2020, 03:22:05 AM »
Here is something that might help

LowGear

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Re: Diesel in sump
« Reply #4 on: April 27, 2020, 06:28:11 PM »
Have you sniffed around for fuel?  Does the dipstick smell like diesel?  Isn't there a dye you can put in the oil as a one time test?  Too simplistic?
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scott p

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Re: Diesel in sump
« Reply #5 on: April 30, 2020, 08:12:26 PM »
For what itís worth

My Hr2 was getting fuel in the oil. I took the valve covers and the pump cover off and started it up. The high-pressure pipes were dripping fuel from the top compression link to the injectors. When I took the compression nut off I could see that both pipes were about an eighth of an inch too tall at the injector end on both pumps.

I donít know why things didnít line up. The pumps are new aftermarket made in turkey. The pipes are original HR pipes.

The dilemma rang a bell in that I recalled facing that problem when I built the engine. At that time my response to the problem was to loosen and lift the injector to fit the fitting and then tighten it down again.

Didnít work, today I tried bending the pipe a bit to get it to fit. That was counter productive, couldnít get it to bend where needed.

Finally, I again lifted the injectors, applied the pipes and tightened the injectors. I tightened the lower pipe to pump connection but left the top connecter finger tight.

I then split out a hardwood punch a few inches long. I put the punch on the pipe where it cleared the compression nut and gave it a good rap with a hammer. A sequence of a couple of raps and then look appeared finally to bring the pipes into line with the injectors. I tightened them up and started the engine to see and saw that the leaks had stopped.