JP3M - Oil blowing from exhaust

[Canopus36]

Did a top end re build last summer. Heads skimmed(one head swopped due to lack of enough metal to skim)and presssure tested. New valves, guides and springs fitted and all gaskets replaced. head gaskets were new original Lister complete with shims to achieve clearances.

 

Engine now runs as sweet as, however, I am getting oil blowing out through the exhaust stack. Hardly done any hours since re-build. A suggestion was the engine needed to settle in/rebed but doesnt seem to be having any effect. Oil pressure is a constant 18 dropping to 15 when running temperature achieved. The oil in the exhaust [fonhas not been combusted as there is no smoke to speak of. Has anyone got any suggestions as to what the problem might be before I start stripping the heads down again?

[Timleech]

Did a top end re build last summer. Heads skimmed(one head swopped due to lack of enough metal to skim)and presssure tested. New valves, guides and springs fitted and all gaskets replaced. head gaskets were new original Lister complete with shims to achieve clearances.

 

Engine now runs as sweet as, however, I am getting oil blowing out through the exhaust stack. Hardly done any hours since re-build. A suggestion was the engine needed to settle in/rebed but doesnt seem to be having any effect. Oil pressure is a constant 18 dropping to 15 when running temperature achieved. The oil in the exhaust [fonhas not been combusted as there is no smoke to speak of. Has anyone got any suggestions as to what the problem might be before I start stripping the heads down again?

 

Were the pistons removed or disturbed in any way? If so, then it could indeed be that the rings are not bedded in. It's possible to get oil passing the rings and going to exhaust without burning.

Has it got oil feed to the rockers like a JK? If not, how much oil is in the heads?

 

 

Tim

[steamraiser2]

It sounds very much like worn oil control rings I'm afraid.But before you get your spanners out what oil are you using? I have seen them pass oil because of incorrect lubrication before.

[Canopus36]

Were the pistons removed or disturbed in any way? If so, then it could indeed be that the rings are not bedded in. It's possible to get oil passing the rings and going to exhaust without burning.

Has it got oil feed to the rockers like a JK? If not, how much oil is in the heads?

 

 

Tim

Hi Tim

 

No pistons not touched at all. As far as Im aware no capilliary oil feed to rockers as in JK, since the new oil which we put in is still there. There is about 1/4" of clean oil in the valve side of the heads. Lubrication is just from the greasers.

 

However two or more of the head studs have slight traces of oil on the tops,and I did wonder wether to re-torque the heads to 100 Ft/lb/sq" again.

 

It sounds very much like worn oil control rings I'm afraid.But before you get your spanners out what oil are you using? I have seen them pass oil because of incorrect lubrication before.

 

Oil used for last 8 years is Morris XHD30 Ringfree.

[steamraiser2]

XHD30 is a little too detergent for a JP, unless you have a full flow oil filter conversion fitted.Even with a filter conversion this oil is likely to be a little harsh. Presuming that you have standard Listard type chrome liners it is likely that the exhaust oiling is down to accelerated wear to your oil control rings. Golden Film is an appropriate straight oil for an older type engine such as yours. The guidance in the original Lister manuals is still valid today.

 

Changing the rings on a JP is a straight forward job. Remove the heads and crankcase doors and undo the big end bolts on one cylinder at a time. Pop the con rod upwards until the piston rings are clear of the block top. Change the rings and refit using a decent ring clamp. Simples!

 

Marine Engine Services carry the rings so it's not the end of the world.

[Timleech]

XHD30 is a little too detergent for a JP, unless you have a full flow oil filter conversion fitted.Even with a filter conversion this oil is likely to be a little harsh. Presuming that you have standard Listard type chrome liners it is likely that the exhaust oiling is down to accelerated wear to your oil control rings. Golden Film is an appropriate straight oil for an older type engine such as yours. The guidance in the original Lister manuals is still valid today.

 

Changing the rings on a JP is a straight forward job. Remove the heads and crankcase doors and undo the big end bolts on one cylinder at a time. Pop the con rod upwards until the piston rings are clear of the block top. Change the rings and refit using a decent ring clamp. Simples!

 

Marine Engine Services carry the rings so it's not the end of the world.

 

Before going to those lengths (which more than likely are necessary), just try mopping all the oil out of the heads & running it for a while, see whether there's any difference.

 

Another outside chance, since it seems to be a problem which has started coincident with your top overhaul, is that some debris found its way into one of the cylinders while the heads were off and has scored one of the liners. I think it would have to be fairly serious scoring though, so unlikely.

 

Tim

[Canopus36]

Before going to those lengths (which more than likely are necessary), just try mopping all the oil out of the heads & running it for a while, see whether there's any difference.

 

Another outside chance, since it seems to be a problem which has started coincident with your top overhaul, is that some debris found its way into one of the cylinders while the heads were off and has scored one of the liners. I think it would have to be fairly serious scoring though, so unlikely.

 

Tim

Thanks Tim will try mopping the oil from the heads but Im erring on taking the exhaust manifold off and seeing if I can see if the problem is localised to one or all cylinders. Whatever happens, I think its de-water and heads off again. Re a similar post do you recommend using heldite to put the head gaskets back on with?

 

Ken

[Timleech]

Thanks Tim will try mopping the oil from the heads but Im erring on taking the exhaust manifold off and seeing if I can see if the problem is localised to one or all cylinders. Whatever happens, I think its de-water and heads off again. Re a similar post do you recommend using heldite to put the head gaskets back on with?

 

Ken

 

I'd use Wellseal unless the joint faces are all absolutely perfect, in which case just a smear of oil as per the book, or if they're really bad Heldite might be worth a try though silicone instant gasket might be a better bet, just a thin bead of silicone around the water spaces and pushrod tubes each side of the gasket (not around the liner tops).

I've never used Heldite but aim to try it on a 'difficult' job (not a JP) shortly where all else has failed and remachining is not an option.

 

Tim

Edited June 6, 2011 by Timleech

[flatplane8]

Thanks Tim will try mopping the oil from the heads but Im erring on taking the exhaust manifold off and seeing if I can see if the problem is localised to one or all cylinders. Whatever happens, I think its de-water and heads off again. Re a similar post do you recommend using heldite to put the head gaskets back on with?

 

Ken

Hi,

Did you get to the bottom of this? I also seem to have a lot of black lunge leaking out of the exhaust at various joints. There are no signs of anything if I hold my hand over the exhaust outlet, so I'm not sure what it is. It's a bit oily, so maybe unburnt fuel? Oil level seems normal but the engine does smoke a bit (white smoke, not blue or black).

[flatplane8]

Might have answered my own question, while fixing a couple of diesel leaks yesterday, I discovered that one of the injectors wasn't seated properly so was pumping diesel back up into the top of the cylinder head. This was probably causing the engine to overfuel, hence the back gunge.

 

Will see on the next trip out, but the exhaust seemed cleaner after I'd fixed it.

Edited August 15, 2011 by flatplane8

[Canopus36]

Stripped her down again to discover oil coming from No1 cylinder. So have fitted brand new ex MOD liners with new seals, new piston rings and used wellseal on the heads. Injectors overhauled and then all re-assemebled which seems to have cured the problem. Therefore we suspect the rings on No1 piston were the culprit.

[flatplane8]

Stripped her down again to discover oil coming from No1 cylinder. So have fitted brand new ex MOD liners with new seals, new piston rings and used wellseal on the heads. Injectors overhauled and then all re-assemebled which seems to have cured the problem. Therefore we suspect the rings on No1 piston were the culprit.

Good news! Was replacing the liners hard?

[Canopus36]

Good news! Was replacing the liners hard?

Not if you have the right kit. The hardest bit is undoing the conrods from the crank and geting them with pistons on the end up and out of the block. Richard has a steel disc with a hole in the centre and a long piece of 25mm threaded rod with several lock nuts on. The disc is the same daimeter as the inside of the liner. Place under the bottom of the liner along with a pice of flat bar(again with a hole in the centre)which goes across across the top of the cylinder. Two strategically placed small bottle jacks across the top of the block under the flat bar, pops em out like a cork from a wine bottle. Simples !!!!

 

[Timleech]

Not if you have the right kit. The hardest bit is undoing the conrods from the crank and geting them with pistons on the end up and out of the block. Richard has a steel disc with a hole in the centre and a long piece of 25mm threaded rod with several lock nuts on. The disc is the same daimeter as the inside of the liner. Place under the bottom of the liner along with a pice of flat bar(again with a hole in the centre)which goes across across the top of the cylinder. Two strategically placed small bottle jacks across the top of the block under the flat bar, pops em out like a cork from a wine bottle. Simples !!!!

 

 

It's not always that straightforward, occasionally with a neglected engine it can be a major struggle to get the liners out.

Also (being pedantic again) you really would struggle to get the pistons + conrods out together They have to be separated, pistons out of the top & rods out of the side, that last part is a bit of a fiddle to do.

 

Tim

Edited August 21, 2011 by Timleech

[steamraiser2]

We recently had to get a set out of a JP2M. Not saying that they resisted but it made our sixty ton puller struggle!

[Timleech]

We recently had to get a set out of a JP2M. Not saying that they resisted but it made our sixty ton puller struggle!

 

Twenty-something years ago I spent the best part of three days with a JP2 crankcase on the floor, with seriously heavy screw pullers, major heat, all sorts of persuasion I could think of, getting the liners out.

These days I have a 50 ton hollow ram which ought to cope with even the worst cases, but I haven't met one that bad since then.

If all else fails, filling the water space with hydrochloric acid is said to help.

 

Tim

[flatplane8]

Twenty-something years ago I spent the best part of three days with a JP2 crankcase on the floor, with seriously heavy screw pullers, major heat, all sorts of persuasion I could think of, getting the liners out.

These days I have a 50 ton hollow ram which ought to cope with even the worst cases, but I haven't met one that bad since then.

If all else fails, filling the water space with hydrochloric acid is said to help.

 

Tim

 

Tales like that are why I decided to curb my enthusiasm and not try and fiddle with the liners when the heads came off.