Benford 2500 - Is my Lister-Petter engine overheating?

[stan.gibbs]

Hi All

I'd be very grateful if someone could help me diagnose a problem (or even if there IS a problem) so that I can fix our dumper. I have 20 years experience with petrol engines but absolutely none with diesel engines so I'm very happy to take any advice or guidance on this. I need to know if the dumper engine is overheating and (if it is) what parts I'll need to order from the UK to fix it.

Some background:

We have a 1988 Benford 2500 out on a small job in France, in the countryside literally miles from anywhere. It has a Lister-Petter twin cylinder TR2 (I believe). The engine number is 3800734TR2A007.

The engine has been working fine for the last 4 months, and still starts perfectly, although it has oil seeps all over it which seem to be increasing. These are:

1. small seep from forward cylinder exhaust manifold port.
2. various seeps from where cylinders meet engine block
3. another seep on left engine side coming out from under the cover (therefore exact location unknown)
4. small seeps from cylinder head, such that the cylinder fins are oily
5. Lately these have increased to include spitting tiny droplets of oil out of the cowling that holds (I assume) the flywheel.

I washed the engine yesterday and then ran it to assess the extent of the leaks. The pictures attached show some of these leaks that have appeared since the washing. The arrow marked with a red X shows the point where the oil was bubbling (see below).

Basic problem:

We have just begun using a new dump site that's the farthest yet from the project (a return trip of about half a mile over slightly bumpy fields). After each run it seems to me (but then I really do lack experience with diesel engines) that the engine is running too hot. It feels hotter than I've ever felt it run before, and the oil droplets caught at the junction of cylinder head and engine block are slowly bubbling from heat.

The oil level in the engine is not low. If anything, it's slightly overfilled.

We simply can't afford to blow this engine so I'm being cautious and adopting a stitch-in-time approach. I've taken the dumper out of service until I can get some advice on whether it's safe to run.

I don't know if that running temperature (hot enough to bubble oil between cylinder and engine block) is normal, or if it suggests a problem with the oil pump ... or something else.

I'm happy to pull the engine out and dismantle it if absolutely necessary but I need some guidance to diagnose the problem so I can buy the appropriate parts.

If we do go for a strip-down and repair (at least enough to keep it in service until we get it back to the UK next year) I'm assuming I'll need a crankshaft oil seal to stop the spitting flywheel problem, as well as a gasket set for the cylinders?

However, we really are in a remote location so if there are going to be issues with disassembly or re-assembly I need to know about them before we start in order to plan things properly. We pulled the boom and dipper off a JCB digger last month to replace the bearings and it took 3 days of improvising with equipment because we don't have a fully equipped workshop here.

So it would be great to know:

1. If there is really a problem with temperature.
2. what's causing it, or any test I can do to pinpoint what's causing it.
3. whether I can fix it with the engine still in the dumper
4. any issues that will probably occur or specialised tools needed.

If anyone can give me some guidance I'd be very grateful. I'm hoping someone may write: 'You got no problems. It's normal for the engine to be that hot. Put it back in service and carry on with the job. Nothing you can do will blow that engine.' Or is that being TOO hopeful?

Kind regards

Stan

[Jeremy Rowland]

I hope that I am correct in saying that this is an aircooled diesel? In which case it should not overheat unless you are operating it at a very high altitude.
Small bubbles of oil from the headgasket suggest a small leak but that should not really cause a problem, the oil leak from the flywheel end sounds like a blown seal, again a problem that can be tolerated.
The only things that I can think of checking would be firstly that the crankcase breather is not blocked as this would only aggravate the oil leak problems and also check that if there is a cooling fan and cowling fitted then just check the fan operation and also check that there is no blockage of muck around the cylinder cooling fins which could prevent the flow of cooling air.
Hope this helps.

Jeremy

[FOWLER MAN]

Hi Stan,
I agree with Jeremy It sounds as though the crank case breather is blocked.
If it is you will notice excessive pressure at the dip stick if you remove it with engine running.
These engines do run hot, but the oil may be blown onto the cooling fins on the cylinders from the leaking flywheel / fan causing it to smell hot and giving the impression of running hotter than it realy is. Dust can also adhere to this oil, blocking the fins and prevent the cooling process as stated by Jeremy.
Hope this helps.
fred

[essexpete]

Give it an oil change if you have not lately.

[stan.gibbs]

Sorry Jeremy; yes, I forgot to state that it was air-cooled. Thanks to everyone for the suggestions. I will definitely check the breather. Fred's point about the engine 'seeming' hotter than it really is, is a good one that I hadn't thought to check before. I'll attempt to test that today. The oil was changed about 40 hours ago Pete.

I've been thinking over-night that maybe the oil level being slightly above 'max' might be responsible? The increased oil pressure would push more oil out of old leaks and could be reducing oil flow if there was any frothing. Does that seem feasible? I've no experience with these engines so I'm not sure how tolerant they are of oil levels.

Regards

Stan

[Jeremy Rowland]

Overfilling an engine with oil would certainly contribute to oil leaks as this increases the crankcase pressure.

Jeremy

[stan.gibbs]

I may have sorted it! Checked everything and found no blockages. It seems as though it was the oil level. Having reduced it (by not very much because it wasn't that much overfilled to begin with) the oil leaks and cylinder temperature have definitely reduced. I'll need to test it on a day's work to be sure though. Who'd have thought that an old diesel engine would be so sensitive to some extra oil? I thought they built these things with huge tolerances.

Thanks for all your help. If it turns out the problem is continuing I'll try to get as much info as poss to post on here.

Regards

Stan

[Cliff A]

Stan,
The reason for the over heat due to high oil level is more likly to be the crank ballance weights and big end caps splashing through the oil surface of the higher level rather than exesive pressure, these listers do have a colser fin spacing on the cylinder barrells and do suffer from blockages of oil and dust mix take the covers off and wash the finns out with a jet wash or some detergent and a hose. It will go on for years!
Cliff

[bobcat773]

Stan
I read your post with intrest as a former lister petter rebuilder as well as a owner my thinking is your crank seal behind the flywheel is leaking to high a leval of oil will make the leak even worse So my thoughts and from preoivouse expreince is that the fan picks up the oil carrys it in the cooling air flow around the clys and head hence your oil drip what I have done in the past and sems to work pretty good is with the engine COLD and running on idle is to pour engine degreaser in the fan intake(between fly wheel houseing and gearbox ) turn it off let it soak for a few hours doing this last thing in the day is good and letting it soak over night after the soak fire it up again and with a good hose flood fan area with water to rinse out degreaser and muck
If the oil problem still contuine you will have no choice but to pull engine out remove flywheel and fit a new seal hope this helps Phil