Lister Engine Forum

Lister Engines => Petteroids => Topic started by: Lispet on April 25, 2015, 08:45:13 PM

Title: Lister Petter injection pump
Post by: Lispet on April 25, 2015, 08:45:13 PM
Hi there to you all.

Thanks to the admin for getting me onto your site.

I hope I am posting in the right section, cause we have a Lister Petter lpa2 air cooled 2 cylinder engine and I would like your thoughts on an issue we are having with the two injection pumps. Since we bought the machine, she is a bit hard to start when cold.When she was bought, the previous owner didn't  wire up the cold start device.This was duly done, but she was still not great.

We then decided to install a thermostart device with the fuel  supply taken from the leak off circuit.Still not great to be honest but no problems when warm or even if she was switched off for an hour or so.Then one day she would start, but would not stay running so I took off the air intake pipe and she stayed running then (could be pure coincidence).The same thing happened again recently but this time no improvement.

We took out the injector pumps to check them and it was found that both were faulty. We purchased two new ones but they just will not work when installed despite turning them every which way.They would pump away when hand pumping them with some fuel rigged up, but nothing when installed.Only one injector worked at first, but then nether worked then.

We finally bit the bullet and took of the gear cover behind the crank pulley and she seems not to be advancing the governor, but retarded it ok and the rack that controls the pumps somehow.The large spring which I think  is for the throttle was slack.We tightened this up by moving the little pin on the throttle linkage to one of the other positions ( maybe wrong to do so) but now this spring is better tightened up, and installed the two pumps  again and made sure they were being operated by the governor.Now both injector pumps are working plus injectors.We cant put the engine back together again because some fuel pipes and gaskets have to be replaced but  when thats done hopefully she  will work again after some real head scratching was done.By the way the new advance/retard lever on the new pumps are more stiffer than the old ones.

What I would like to know is what is the correct way these pumps should  be removed and installed to avoid disturbing the settings  on the  pump and govenor, thanks and sorry about the long winded question. regards, James.
Title: Re: Lister Petter injection pump
Post by: Lispet on April 26, 2015, 09:44:29 PM
Finally got her going but it was all a bit of a heartache.The setup is not so good.
Title: Re: Lister Petter injection pump
Post by: dieselgman on April 26, 2015, 09:50:51 PM
You are not alone in struggling with that engine model... Lister only produced it a couple years before going to water-cooled. The governor and fuel rack assembly can be a real pain and is mostly completely hidden inside the block so must be assembled largely by "feel". If you are not experienced with it, can be a real challenge.

Title: Re: Lister Petter injection pump
Post by: Lispet on April 26, 2015, 10:17:00 PM
Thank you, I don't know what the correct procedure is. It would help greatly if they put an inspection plate that you can easily take off over the governor mechanism only, to check that everything lines up with the fuel pump rack instead of going to the trouble of removing a pulley and seven bolts on a cover.

I think you are  supposed to only remove an injection pump one at a time which is bad if you want to check the operation of both, which I did......the  hard way ::)
Title: Re: Lister Petter injection pump
Post by: Lispet on May 01, 2015, 12:19:13 PM
I still had some issues with the engine. After I put everything back she just would not start despite trying everything, but was running before.

I then removed the drive belt and the crank pulley plus the hydraulic pump. I then decided to try to start her then,and to my surprise,she fired up.

So.,I decided to put everything back again except the pump,and she started again. So this all means that I am guessing that what was the issue was she was trying to start while under load and trying to operate the hydraulics.

On another issue how are these engines supposed to breathe?

Title: Re: Lister Petter injection pump
Post by: dieselgman on May 01, 2015, 01:06:25 PM
I don't know what machinery is attached to your engine, but there needs to be some sort of unloading valve to allow for easy starting - especially when cold. I have seen many of these used on portable welders and they often require a pretty substantial pre-heat to start up without a considerable amount of cranking. They have available optional DC preheating elements that fit into the inlet manifold for this purpose.

On another issue how are these engines supposed to breathe?

Not certain of your meaning... there are at least three somewhat related things happening regarding air pressures and flows: 1.) combustion air and exhaust. 2.) cooling air flow and exhaust. 3.) crankcase pressure/vacuum and venting.

#1. Make sure your rings and valves are in good condition and that the air filter is clean... these engines are known for weak valve trains and they often damage rocker arms and push rods. They also use hydraulic tappets (cam followers) that require careful attention regarding clean lube oil and manual compression to relieve air once disturbed or otherwise serviced.

#2 These models rely on an axial cooling fan assembly that is belt driven. They are known for failing ball-bearings which can increase belt wear and cause belt failures = subsequent overheating. The fan can lose its efficiency due to dirt and dust build up. They must be kept fairly clean to avoid cooling related issues. You MUST pay close attention to belt maintenance or face engine overheating issues.

#3 The crankcase should run a slight vacuum if the rings and valves are in good condition and properly adjusted.

Title: Re: Lister Petter injection pump
Post by: Lispet on May 01, 2015, 01:27:50 PM
Thanks for the replys, the engine is in a benford 1.5 tonne dumper. She had an inlet manifold heater that was not wired up to it by the previous owner. I changed the OE unit with a thermostart unit which has a flame coming from it for a few minutes which is working fine.

I just was wondering how the crankcase is vented as all engines need that,don't they? In other engines there is a hose that is connected from the engine to the air cleaner. How do these engines do this task,that was my question, cheers.

P.S when you say unloading valve,do you mean on the engine,or the equipment it's attached to?
Title: Re: Lister Petter injection pump
Post by: dieselgman on May 01, 2015, 03:21:52 PM
We are not too familiar with Benfords here... but we were talking of the hydraulic system in general. There should not be any load/pressure from the pump during startup/warmup.

Lister uses an internal vent into the inlet manifolds to create the crankcase vacuum.

Title: Re: Lister Petter injection pump
Post by: Lispet on May 01, 2015, 04:08:34 PM
Yeah,"Benfords"are a British built machine.
I would take a guess that the operating lever that lowers or raises the bin was in the raised position and so the hydraulic pump was putting a load on the engine while starting,and I just didn't notice it.

I assume the vent is not visible on the outside
, hense the internal part?;-)

Title: Re: Lister Petter injection pump
Post by: mike90045 on May 01, 2015, 07:39:08 PM
While starting, I have to apply force to the hand crank after I get up to speed.   Tom told me to lean DOWN on the starting handle to build speed, and save strength for the pull up, when the decompress is disengaged.  Mine fires on the first compression at 35F.  Below that, I have to crank through 1 more compression when it's really cold.
Parasitic loads (the belt to the generator or whatever) can add enough drag, that you can't build up enough speed, and thick oil in the crankcase can also slow it down.
Title: Re: Lister Petter injection pump
Post by: Lispet on May 01, 2015, 08:18:01 PM
We used to have a single cylinder "Petter" dumper engine that was a manual start which you would have to have the "knack" when starting from cold, but easier when warm.This present engine is electric start though.
Title: Re: Lister Petter injection pump
Post by: Lispet on September 03, 2015, 12:03:22 PM
HI again, is 22 and 28 bar compression pressure enough for ignition to occur on this engine?  The pushrod tube seals on the head side was leaking and I removed the pushrods to try to seal them up instead of removing the head,which it seems to have done. Compression was checked before and after removal,and it is generally the same on both checks. She seems to be a right bugger to start when cold,even worse now. There is black smoke while cranking,but still not firing. She will at times start in the evenings sometimes,but more often than not she won't and always with heat.

How good should the lpa2/3 engine be at starting from cold?
Title: Re: Lister Petter injection pump
Post by: listard-jp2 on September 03, 2015, 03:44:18 PM
Where abouts are you located in the UK, as I know of a couple of retired Lister Petter service engineers that are very familiar with the LPA/LPW range of engines, and may be able to help you out.
In a prevoius job I worked with Benford Equipment, and as I was leaving the LPA2 equipped Benford dumpers were just been introduced, never had much to do with them, other than routine servicing, at the time they seemed like very good cold starting engine.

From the compression pressure figures that you have quoted, that should be more than enough to get a easy cold start.

Another factor to consider is the spill timing (quite easy on these engines as you loosen the fuel pump and add or remove shims as required, under the base of the pump, this can be done without removing the pump)

Also poor condition of the fuel injection equipment will have the effects you describe, have you observed the spray pattern of the injectors out of the engine, ie turn the engine over with the injectors out of the engine but still connected to the engine fuel pumps.

It is an unfortunate aspect of the fuel pump design on these engines that they cannot be reconditioned, because the fuel pump body forms the element of the pump, so you will require a complete new pump if it has wear on the plunger or the bore which it runs in.
Title: Re: Lister Petter injection pump
Post by: Lispet on September 03, 2015, 09:25:28 PM
Hi, thanks for the reply.Yes I have got the injectors tested and they are spraying in a cross pattern.The old injection pumps were kaput, even though the engine was running, but the linkage that is operated was very free to move over and back.This linkage on the new ones are more stiffer.The shims underneath were just put back as was, but how can you remove them without taking off the pumps?

Yes I was told that some of them pumps can be reconditioned and others cannot.The fact that there is black smoke while cranking would suggest that there is enough fuel been injected.Since the pushrods were removed, she has gotten worse though cold start was not good, but I cant see how this has any bearing on it since the compression is the same as it was before removal.

By the way, I am in Ireland.
Title: Re: Lister Petter injection pump
Post by: Lispet on September 04, 2015, 10:42:02 PM
I checked the compression pressures and they are still roughly the same.I turned over the engine with the injectors removed and while I was standing up, one cylinder nearly blew my face off, and the other not so good.But, here is the confusing part, the cylinder that had slightly lower pressure was the one that had a lot of air coming out, and the other one which had higher pressure was not as strong. How can that be?

She did seem to start a little better afterwards though.Could the cylinders be "flooding"? It would seem like it, but I dont know.
Title: Re: Lister Petter injection pump
Post by: Tom on September 04, 2015, 11:29:05 PM
Sounds like 1 cylinder has low compression. As a rule of thumb compression differences between cylinders should be within 10% max. Your numbers seem to be quite a bit over that. I would suggest checking the valve lash, and then retesting the compression with a shot of motor oil down each injector hole before testing.
Title: Re: Lister Petter injection pump
Post by: Lispet on September 04, 2015, 11:55:03 PM
Thanks, the thing that's confusing me is the cylinder with the lower pressure is the one that has lots of pressure behind it when it comes out of the cylinder, and the higher one has less ???

She does start after the cylinders are "cleared" out as I mentioned too.

By the way, with the hydraulic tappets, would there be any lash?
Title: Re: Lister Petter injection pump
Post by: dieselgman on September 05, 2015, 12:45:15 AM
Regarding those hydraulic tappets... servicing can be a real pain. There will not be any lash. If you remove any of the rockers (or pushrods), you will have to be very careful about compressing the tappet before turning over the engine again or you can have valve and push-rod damage from the valve contacting the piston crown. Normally if you assemble and give the engine about 45 minutes to "settle", then the tappets will become compressed on their own. There is a special tool for the job that basically is a lever that allows you to compress the lifters one-by-one.

A careful inspection of the exhaust ports will tell you something about both compression and fuel injection in that any abnormality will show up in excess carbon or a wet port. These engines seemed to have a lot of problems with the valve trains.

Title: Re: Lister Petter injection pump
Post by: Tom on September 05, 2015, 12:51:09 AM
Never mind the lash adjustment then, the thought was to eliminate one possible source of a compression leak. Low compression will be due to either rings or valves.
Title: Re: Lister Petter injection pump
Post by: Lispet on September 05, 2015, 11:14:03 AM
Yeah the online manual that I have talks about the "bleeding down " of the tappets. I noticed that while installing the rods and tightening down the nuts,if you turn over the engine manually with a socket on the crank pulley,suddenly the engine would "lock",and then after a few minutes it would free up. So that would make sense. But she will start at some stage.

I tried to start her again this morning and I turned over the engine with the stopper on, and turned her over for a few turns. I then gave her some heat and she started relatively quickly with the stopper off . Someone mentioned that if the exhaust is too long,it may affect the breathing of the engine?

Could the breather be a cause?