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Lister ST2 fuel, oil, an pressure, oh my!


Adasha_machining

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Hello all, 

 

An online friend of mine pointed me in this direction from a machinist board we frequent. He noted the post made by RLWP regarding fuel in the oil. 

 

So, a brief description. I'm not a boater, nor is my 14.6hp Lister a boat engine. It's connected to a generator. I have a machine shop, and the old Lister provides me with 3 phase power. And that it does very well. The engine is a friend of mines. It was his father's. I've been using the engine for about a year, but I have maybe only 30 running hours on it since not all of my machines are 3 phase. 

 

I've always had a few issues with the engine, but were usually minor. Unnntilll, the crank case over flowed with "oil" the other night. 

 

So, all stop.. do not pass go, do not collect $200... 

 

I've not had the time to really dig into the engine yet, but I'm hoping to do so tonight. However, the post I mentioned above has helped point me in a direction in which I believe I've narrowed down the fuel leak. So, I'm feeling somewhat confident in that fix - until I dig into it tonight possibly. 

 

However, I'd like to bring up a few other topics I'm concerned about. 

 

The unit leaks oil like a siv. Always from the valve covers. However, since I'll have them off, I'm sure I'll find some reason for leaking. However, if someone has clues to post me in a direction, it would be helpful. 

 

Also, I've always been concerned with oil pressure. The gauge doesn't go to zero - I assume it froze with moisture in it once upon a time. When I start the engine, the pressure pops up to (what the gauge reads, anyways) 40, and jiggles (I understand it's some kind of piston pump that would pulse?) But the pressure drops after some time. To the point it may bottom out to "zero"... I don't like that. I find it extremely concerning. I did read that any gauge movement is good movement, but no movement after some time doesn't seem good. 

 

What kind of simple "dash" gauge would be a replacement? Having a zeroed gauge would be good, but any suggestions on maintaining oil pressure? 

Is there anything I can do with the sensor to ensure it's not part of the problem? 

 

The engine itself has not seen any "love" in many years. Since I've run into a road block with it, I feel it could use a good tune up... What would that entail? 

 

Since I have fuel in the oil, I'll be doing a full oil change w/filter, I'm going to check over the injectors and pumps to ensure connections are tight. I recently checked and blew out the air filter. 

Anything else specific? 

 

The engine runs great. There's an electric fuel pump on it, I guess the mechanical pumps are no good? I installed a small needle valve near the valve covers to bleed the line at start up. Once bled (10 seconds), it starts right up. In the winter, same thing, but with a shot of start fluid hosed into the intake pipe and starts right up. No black smoke, a bit of hazy white. The muffler is vertical out the top with one of those flappers on it. That flapper bounces around for 30 seconds then once the engine settles down it sits open like a 1/2" and barely moves as the engine hums (read: pounds!) away. It is an air cooled Lister afterall, it's loud!

 

I appreciate any feed back. I can post any pictures desired. 

I am apart of another machinist message board, but I have a tendancy to hang around new places and share knowledge I may be able to contribute. 

 

Thanks!

Shawn 

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Some comments.

I assume that by valve cover you meant what we, in the UK, in the main call the rocker cover and not the side cover that covers the injector pumps and push rods.

 

The rocker covers normally use very thin gaskets you will probably need new ones.

 

When you get the rocker covers off make sure the vertical breather tubes are clean because they allow crankcase pressure into the inlet manifold. If blocked the pressure will tend to make the engine leak.

 

An electric oil pressure gauge is not something I associate with the S series of Listers. I would expect it to be a mechanical gauge. As for a suitable replacement all I can say is any matched pair of sender and gauge where the sender has the correct thread to the drilling in the engine.

 

I am all but sure it's a direct injection engine so should start very easily with no need for starting fluid unless you are way up north. The need for it may indicate a loss of compression and link that with the oil leaks it  might indicate badly worn pistons, rings and bores.

 

Mechanical  fuel pumps are fine, I expect it was easier to fit the electric pump than find a mechanical one or, overhaul kit in Canada when it failed.

 

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The leaks will almost always be fractured copper pipes in the valve chest, usually the leak back pipes. They should all be removed and annealed as part of a major service to prevent metal fatigue cracking.

 

These engines will run with little oil pressure for years providing it is oil and not fuel!

 

I would fit a mechanical oil pressure gauge for simplicity.

 

 

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Hi Tony,

 

yes, the rocker covers. 
everything under the rocker cover looked very clean and clear, for what I’m sure is a 50 year old engine.

oil does splash its way up there. 
I did find the leak tonight. The two nuts on top of the fuel pump on one of the cylinders were loose. 
I tightened those up, changed the oil. Got the oil level perfect so it’ll be easy to keep an eye on the level. 
 

my pressure gauge is mechanical. I will look for a matched sender and gauge then. Thank you for the suggestion. 
 

I am in Ontario Canada. A week ago it was -17*C. The engine takes too long to start. It starts draining the battery. A quick shot of starter fluid gets it going. Tonight it was 10*C, starts up fine without fluid. 
 

thanks

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3 hours ago, Adasha_machining said:

Hi Tony,

 

yes, the rocker covers. 
everything under the rocker cover looked very clean and clear, for what I’m sure is a 50 year old engine.

oil does splash its way up there. 
I did find the leak tonight. The two nuts on top of the fuel pump on one of the cylinders were loose. 
I tightened those up, changed the oil. Got the oil level perfect so it’ll be easy to keep an eye on the level. 
 

my pressure gauge is mechanical. I will look for a matched sender and gauge then. Thank you for the suggestion. 
 

I am in Ontario Canada. A week ago it was -17*C. The engine takes too long to start. It starts draining the battery. A quick shot of starter fluid gets it going. Tonight it was 10*C, starts up fine without fluid. 
 

thanks

 

Not done anything on STs  but on other S Series it is pumped up to the rocker gear, not splashed. I am trying to remember where the oil pipe(s) run, I suspect it's inside the push rod case.

 

I suspected you were in very low temperatures.

 

Does the generator room get hot when the engine is running? I am pondering if the oil for low ambient temperatures may be getting too thin if generator house temperature gets hot from the engine.

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Oh, excuse me, you’re right. Oil distribution is via small pipes to all the pivot points around the rocker case and lower pump housing. 
The generator is housed in a rickety old steel enclosed trailer. It appears it may have been an old city road crew power house. Doors front and back, large windows with expanded metal, expanded metal vent ports in the sides (no glass or anything), wind whistles through. So, no over heating for sure.

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