Lister petter engine burning oil and smoking badly, greenmech 150

[gensetsteve]

Difficult without having the engine on the bench. I can't imagine a piston drawing that much oil even if it had no piston rings on every induction there will be an exhaust so the oil would be pouring out the exhaust. I would say more likely the oil delivered to the head is dribbling down the valve seal or through a crack in the head I know you have new seals but defects do occur in manufacture or wrong seals in packet. When you crank the engine you replenish the pool of oil in the head while you scratch your head and have a brew a few more cc's of oil has made it down causing it to hyd lock. A long shot but unless we have overlooked something really obvious can't think of anything else.

Another thought is the amount of oil in cylinder may be worth making sure there defo is no oil way from block to head as this will pump oil quickly while cranking.

Edited October 6, 2015 by gensetsteve

[njm]

Difficult without having the engine on the bench. I can't imagine a piston drawing that much oil even if it had no piston rings on every induction there will be an exhaust so the oil would be pouring out the exhaust. I would say more likely the oil delivered to the head is dribbling down the valve seal or through a crack in the head I know you have new seals but defects do occur in manufacture or wrong seals in packet. When you crank the engine you replenish the pool of oil in the head while you scratch your head and have a brew a few more cc's of oil has made it down causing it to hyd lock. A long shot but unless we have overlooked something really obvious can't think of anything else.

Another thought is the amount of oil in cylinder may be worth making sure there defo is no oil way from block to head as this will pump oil quickly while cranking.

 

It is quite amazing how much oil a piston can move , the oil will not be displaced through the exhaust if just cranking due to its weight , But as you say top end issue would be the most probable cause , A Diesel can draw oil on a cylinder with low compression if it requires combustion pressure to back up the rings ie bent rod , rings , valve . But as you say without the engine under your nose its just guess work

[Davidmayo]

Update, the cylinder was fairly full of oil last night, I left it at that stage, and today the oil hasn't drained at all, still at the exact same level. Would have thought if it was drawing up through rings it would have drained back through by now?

 

Anyway I'm going to have the engine out and take the head off for the fourth time!

 

When I last refitted the head I cleaned it up thoroughly and no obvious damage to it.

[njm]

Update, the cylinder was fairly full of oil last night, I left it at that stage, and today the oil hasn't drained at all, still at the exact same level. Would have thought if it was drawing up through rings it would have drained back through by now?

 

No , nothing to force the oil back if the engine is stationary , remove the injector on the bad cylinder get the oil out , crank the engine with NO injector in the bad cylinder , check and see if its filling with oil again , make sure you have the rocker cover off see if the rocker box is flooding with oil , ie far too much oil getting forced up the push rod tubes compare the bad cylinder to the others , if all looks ok test again with the injector in place . if its filling up and the top end is not flooding with oil its going to be the bottom end rings ect , its going to be easier to diagnose the fault with the engine intact , a pile of parts never tells the whole story . Good Luck

[Davidmayo]

I replaced rings this morning and it made no difference, I'm told that the timings gears on this engine are pressed into the shafts without keyways. If the timing had slipped slightly is there anyway the oil could get in? I still don't think that would make a way for oil to get into the cylinder? Getting desperate now, thinking of just giving up and installing a kubuta engine

[njm]

I replaced rings this morning and it made no difference, I'm told that the timings gears on this engine are pressed into the shafts without keyways. If the timing had slipped slightly is there anyway the oil could get in? I still don't think that would make a way for oil to get into the cylinder? Getting desperate now, thinking of just giving up and installing a kubuta engine

 

Forget about the timing gear , have you checked any of the things suggested ?

[Davidmayo]

Forget about the timing gear , have you checked any of the things suggested ?

 

 

I have checked everything, oil flows back down the rod tubes and does not flood the head, it's an incredibly simple engine which is why this is so confusing. There really isn't a lot to check. I have with the new rings in I have pumped out all the oil and got it to run. Still a bit smokey at high revs but nothing compares with what it was.

 

I'm going to attempt to use it tomorrow, if the smoke doesn't clear I will be compression testing again to see if the cylinder with new rings is now any better than the other two.

 

Maybe putting new rings throughout, but didn't want to fork out over £100 on rings if it didn't need doing.

[njm]

Good to hear you have some progress , did you run a glaze buster down the pot ?

[ashtree]

David,

Hope you have got the problem solved now, the thread seems to have gone cold.

If you are still in trouble I think the clue lies in your first post (No 1 inlet valve hit piston hard enough to bend push rod) but no marks on other pistons, clearly the valve was open at the wrong time for some reason.

As all else has failed look for a broken camshaft (I've come across a few in my time on the shop floor). It would be an oblique palm split and the camshaft would still turn as it is rigidly supported but the timing would be different before and after the break.

 

That problem with the oil is gross and I can't see that much getting down the guides, or past the rings for that matter, but if the inlet valve is staying closed at the wrong time creating a vacuum as the piston descends I suppose it could draw oil up past the piston.

 

A bit of a shot in the dark all this but worth a look maybe. Best of luck with it.

 

Graham Illsley.

[Davidmayo]

David,

Hope you have got the problem solved now, the thread seems to have gone cold.

If you are still in trouble I think the clue lies in your first post (No 1 inlet valve hit piston hard enough to bend push rod) but no marks on other pistons, clearly the valve was open at the wrong time for some reason.

As all else has failed look for a broken camshaft (I've come across a few in my time on the shop floor). It would be an oblique palm split and the camshaft would still turn as it is rigidly supported but the timing would be different before and after the break.

 

That problem with the oil is gross and I can't see that much getting down the guides, or past the rings for that matter, but if the inlet valve is staying closed at the wrong time creating a vacuum as the piston descends I suppose it could draw oil up past the piston.

 

A bit of a shot in the dark all this but worth a look maybe. Best of luck with it.

 

Graham Illsley.

 

That was my last theory with the timing, but I think it must have been the rings on the no1 cylinder. Basically I have no idea how all that oil was getting in, but it was also getting into no2 cylinder the last time I had it out as well. Possibly flooding in don't ask me how but when I fill with oil the head floods and those two cylinders share a rocker cover? But it is working well now. May re-open this thread again is I have any problems but all seems ok now. Thanks for everyone's input