Fuel for Petter AB1 diesel engine.

[Andrew TinsleyParticipant @andrewtinsley63637]

I have been overhauling this diesel generator set to cover power cuts in my rural area. I have since been confined to bed with a nasty infection which is limiting my mobility.

So I have been considering what fuel to use when I get back to finishing the overhaul. The handbook and workshop manual are helpful in defining the required fuel and pump diesel fills the bill. There is about 1£ per litre difference between heating oil and pump diesel. So it occurred to me to use the heating oil as a fuel.

Now the Petter AB1 is an old design and somewhat agricultural. I have run it for a short time, on heating oil during an emergency. So it certainly works.

However I have concerns for lubrication of the injector pump. I seem to recall that adding oil to the fuel overcomes this problem. Does it work? If so, how much oil and what grade would be best?

Injector pumps are not overly expensive, so I am happy to take some risk!

Andrew.

[Andrew TinsleyParticipant @andrewtinsley63637]

[OldironParticipant @oldiron]

Adding 10 to 15% of pump diesel will help with the lubrication and aid better running. Adding oil will produce more smoke than you may want and will probably clog up the injectors. I did this when running my Ssangyong 4×4 on chip oil with no problems after 25,000 miles.

regards

[David JuppParticipant @davidjupp51506]

Your oil supplier may be able to give some assistance – this web page has quite a bit of information for example

Guide to Fuel Specifications

Looks like pump DERV may not be as helpful as the grade D Gas Oil in terms of lubricating properties for older equipment…

[noel shelleyParticipant @noelshelley55608]

LETS BE CLEAR ? there are 2 types of heating oil 27sec and 32sec, the first is kerosene the second diesel. Kerosene has little lube and will need help, 25/1 or even as low as 50/1 with lube oil. Vegetable oil (chip) needs no such help being an good lubricator. IF the AB is the same as the AA then there may be a small plunger in the intake with an O ring on it, before starting, remove, fill the hole with lube oil and push plunger home, this is the starting aid and works well even on a frosty morn. DO NOT use kerosene or light distillates with out lube you will wreck the injection system.Should cost be an issue then start on diesel and change to cooking oil when hot. IF the starting aid is not fitted it is easy to make one ! I ran AAs in the 70s, noisy but very reliable. Noel

[duncan webster 1Participant @duncanwebster1]

Friend of mine ran his camper van on cooking oil/diesel mix. Best not to follow him as it created an unpleasant smell of burnt chip fat. The Gardner manual used to tell you how to dispose of used engine oil by mixing it with the diesel fuel. Can't remember the ratio, but Gardners smoked like made for a few minutes on start up anyway. The big diesel backup engines from a nuclear power station I worked at went off to be converted to burn chip fat. They were there to provide emergency backup and had hardy been used.

[Robert Atkinson 2Participant @robertatkinson2]

I've done some research into this for both work and personal reasons. This covered diesel and gas turbine (jet) engines. It is high pressure sliding surface lubrication that is the issue. This is provided at the molecular level rather than as a fluid film. It is a particuar problem with modern direct injection diesel engines. You would think that the older engine would not have issues with this, but the design may have inadvertently relied on the high level of sulphur in the diesel fuels of the time. There were issues with some aircraft turbine engine fuel pumps when the sulphur content in jet fuel was reduced. There was never a lower limit for the sulphur content and the design had been used for years without realisation that it needed sulphur for ubrication. The US military had trouble running Hummers on jet fuel (common fuel requirement for aircraft and vehicles to reduce battlefield logistics). It was only certain makes or even batches of supposedly identical fuel pumps that failed and it was down to the exact composition of steel used for internal parts.
To be on the safe side I would recommend adding maybe 10% of PREMIUM pump diesel fuel to whatever you burn, weven modern standard pump diesel which is low sulphur and contains biodiesel. The premium fuels include additional lubrification additives.

EDIT. I forgot to say that  David Jupp's suggestion of grade D gas oil is a good one. Only problem is most suppliers won't know exactly what is in their red diesel.

Robert G8RPI.

Edited By Robert Atkinson 2 on 02/01/2023 13:09:32

[noel shelleyParticipant @noelshelley55608]

Robert, Your mention of pump failure due to sulfur reduction in the fuel was interesting ! I know of 3 CAV injection pumps run on cooking oil that failed, snapped the pump shaft but the same never happened to Bosch pumps on the same engine. Noel.

[SillyOldDufferModerator @sillyoldduffer]

My take on this is different. The purpose of the generator is to provide emergency cover during a power cut. Therefore, I think it unwise to compromise reliability by running it on cheap fuel in hope of saving money! An emergency generator that doesn't start and run reliably for the duration of a power cut is useless.

Trouble is no-one knows how well or badly an old Petter will run on heating oil. My guess is it would run for a least a few hundred hours before trouble, and given the engine's robust heritage, it might be completely happy forever. Or the oil fails to lubricate and trashes the injector.

Answers are guesswork unless someone has run a Petter for hundreds of hours on the same heating oil available to Andrew.

Related is, how long is the generator is expected to run? UK power cuts are infrequent, and rarely last more than a day. If so the money saved by using heating rather than pump oil is trivial, not worth the risk. However, savings are worth chasing if the generator ever consumes a lot of fuel, running for weeks rather than days.

Power cuts lasting more than a week are very unusual in the UK, so the chance of a long run being needed is worth considering before setting a budget. Thanks to global warming, severe weather events are far more frequent and getting worse. If I lived in a rural area vulnerable to bad weather, I'd certainly think hard about reliable standby arrangements. I feel if it's worth doing it's worth doing well. My first reaction is to avoid cost-cutting Heath Robinson solutions to this requirement.

Dave

[Andrew TinsleyParticipant @andrewtinsley63637]

Seems to be a lot of theoretical replies. To be honest I am only interested in practical results on this type of old Petter engine.

I am using 27 second heating oil in my central heating, so Noel's suggestions are relevant (yes it has the standard "add oil" device for starting). The AB1 is a stroked version of the AA1 thus giving a little more output. Oldiron seems to have a reasonable fix too.

Some people seem to think this is a modern diesel fitted with the latest gizzmos in injection pumps. Not so! it is a very simple and crude device which will keep running when all others fail.

Andrew.

[David JuppParticipant @davidjupp51506]

Andrew, Gas Oil is pump diesel but with much reduced excise duty, so should still give a big saving. A generator would seem to be a legitimate use for Gas Oil.

When I worked on a major Petrochem site, all the diesel engines vehicles used only on site (not on public roads) ran on Gas Oil.

[duncan webster 1Participant @duncanwebster1]

As you live in a rural area there must be farmers, who will have diesel fuel on which reduced duty is payable. If you come to an arrangement with one, you only need to have say 5 gallons at the ready and will be able to get more as needed. Take note of the other thread on diesel space heaters re summer/winter grade diesel.

[Nigel McBurney 1Participant @nigelmcburney1]

I would NOT run any diesel on straight central heating kerosene,I have read somewhere that Gardners were reputed to state that kero mixed with a proportion of clean new lubricating oil can be used in diesels. I cannot remember the ratio quoted but at the time I thought that it was a lot of lube oil per gallon of kero, red ag diesel was the cheap answer but the tax rules have changed regarding use, eg construction plant ,groundcare tractors etc now have to use white diesel which is heavily taxed,Though a stationary engine collector and restorer,I do not use any of my engines for emency power, I have used a 1800 watt Honda petrol generator which I bought over 30 years ago,and this has seen me through many power cuts as in my part of rural Hampshire the overgrown trees and hedges are always bringing the wires down. A petrol engine is economical to run in the smaller sizes,and starts easily provided the carb is cleaned due to the bio fuel clogging any petrol carb,the only snag with my generator nowadays is that the electric from the unic is not sufficiently regulated for modern electronics,so I do not risk using my computer, if this digital method of operating the BT telephone system comes in though the halt on installations is currently halted I would have to get a better regulated generator,so would go for a larger generator diesel with electric start. and better regulation. If your generator is similar to the petter engines down the road on the cress bed I hope yours is a better starter in the winter,a couple of Petters in the dumpers were pigs to start,

[Andrew TinsleyParticipant @andrewtinsley63637]

Hello Nigel,

The AB1 diesel is in fact a very easy starter even when cold. As long as you follow the start procedure laid down in the manual. Mine has been outside in minus 6 Centigrade and started first time with the magic oil prime.

The overhaul was caused by neglect on my part. I have not had a power cut for a long time (The feed into the village was uprated). I pulled it out to check it still ran and give it an oil change, filter changes etc. Much to my dismay there was a large amount of piston blow by. Turned out that the inlet valve was open and condensation occurred in the cylinder, then rust.. I should have sealed off the inlet and exhaust tract before storage. Live and learn!

I have a nasty feeling that we may be heading for power shortages this winter, hence wanting to get it back together.

Andrew.

[noel shelleyParticipant @noelshelley55608]

Nigel, there are a few things you can do to try and remove spikes in the generator supply. Keep a 100w incandesant bulb burning, use a protected socket,DO NOT turn off a heavy load whilst sensitive equipment is plugged in. YES I fear the lights may go off if we have a prolonged cold spell, and Europe is also cold. Noel

[vintage engineerParticipant @vintageengineer]

As of 1st April 2022 it is illegal to run generators on red diesel unless it is for non commercial use.

 

Edited By vintage engineer on 02/01/2023 22:49:34

[Howard LewisParticipant @howardlewis46836]

A few words of caution, about using any old fuel that happens to be available

Fuel Injection equipment is made to single micron precision (Lapped fits) and subjected to pressures of hundreds of bar.

In a lifetime spent in engine manufacture, I've seen these things happen!

Running a diesel engine on kerosene, or Avtur, is very likely to cause very premature damage to the Fuel Injection Equipment.. It will also mean that the power is affected by the different calorific value as well as the changed delivery characteristics. So not a good idea, unless additional lubricating oil is added to the fuel.

Cooking oil may well damage the drive shafts because of increased viscosity, which will increase the torque required to drive the pump, not to mention increasing injection pressures and upsetting the timing of when the injector actually injects. (Over advance can damage pistons / bores )

Fuel Injection equipment, including the length and bore of injection pipes, and injector dimensions and settings, is very carefully matched to the engine, to provide the required performance characteristics. (Using a different injector might change the fuel delivery, or the torque curve shape, as well using injection pipes of different length or bore. It might even bring about pump seizure!).

So, be careful what you change and what fuel you use. Getting it wrong could be VERY costly, not just in terms of F I E damage, but risking drive train damage or piston / bore seizure!

Sorry to be so dismal, but care is better than expensive damage.

Howard

[Andrew TinsleyParticipant @andrewtinsley63637]

Howard,

Thanks for your words of wisdom based on real life experience. Maybe I should not be a cheapskate!

Thanks,

Andrew.

[SillyOldDufferModerator @sillyoldduffer]

One fuel that's highly likely to wreck a diesel engine is petrol. Although made difficult to do at the pump, people occasionally manage to refill diesel cars with petrol. They start and run apparently normally, but hell is unleashed inside the engine. They typically run for a few hundred miles before the mistake comes home to roost.

Problem is petrol has none of the lubricating properties of diesel, which trashes injector pumps, and it washes lubricating oil off cylinder walls and piston rings. It might even get into the bearings.

The military are fond of diesels that run on all sorts of fuels, but they're specially designed for it.

Accidentally filling a petrol car with diesel is much less damaging because the engine will be very reluctant to run at all. The error can be fixed by draining and a good clean. Pricey and embarrassing rather than a trashed engine.

Used frying oil is often used in diesels, apparently without doing any harm. It's important the oil be well used because prolonged cooking heat breaks it down into diesel suitable viscosity. Works well after getting rid of cooking remnants by filtering or settling. Clean new vegetable oil is much less suitable: not sure why, but being thicker I guess it tends to coke up rather than burn efficiently.

A few posts mention Red Diesel. The law changed on this last year, and it's becoming less common. The number of exemptions has been reduced. Any vehicle using a public road has to pay full fuel duty. Bit of a red-herring though, , Andrew can use any fuel he likes for generating electricity in private.

Dave

[Howard LewisParticipant @howardlewis46836]

If you can find a heating oil that corresponds to Red Diesel, (such Gas Oil ) the engine should run quite happily on that.

No point in paying taxes, needlessly!

The problem that engine manufacturers face is that fuels vary from place to place, and even the season (North America use a special winter fuel to partially cater for the low temperatures in and around Canada . Witness the recent blizzards in USA. Under those conditions wax content is important to prevent blocking fuel filters )

Some machine manufacturers dispatch machines, filled with a shipping fuel, so that the engine will start wherever in the world it is sent.

But the engine does not deliver rated power (So fails on stall down tests), and sometimes is very noisy..

The fuel temperature will affect viscosity, altering leakages, (Important at 600 bar and upwards ) and fuel density, and with it the mass of fuel injected.

The engine derives it's energy from the mass of fuel and oxygen, but we control the volume. Hence density (Specific gravity ) and temperature become important, as well as calorific value..

The torsionals seen in a fuel injection pump drive tend to be quite violent, both pumping and unloading after injection ends, so the drive train needs to be strong. So using a higher viscosity fuel, such as cooking oi ,will increase pressures within the system, increasing mechanical loads,

Many years ago, the M O D issued a requirement for engines which would run on almost any fuel (Incase it was found on newly won territory )

This brought about the Rolls Royce K range and the Leyland L60.

The K range were opposed piston two strokes, and the multi fuel ability was obtained by altering the phasing between the upper and lower crankshafts (and the port timings ) by altering the relationship within the gear train connecting them. This changed the compression ratio and the port timing, but took no account of the effect on the fuel injection system of the different fuels. Colloquially, we called them "Peanut butter engines" because they were supposed to be capable of running on it..

Was never sure if the engines actually went into production.. The 2 strokes were powerful on Diesel fuel, but certainly noisy!

At the behest of New Zealand, Perkins experimented with using mutton fat as a fuel. Again, possible but never went into production, as far as i know.

Howard

[Howard LewisParticipant @howardlewis46836]

I hope that "Magic Oil" is not ether. It tends to wash the bores dry with resultant bore wear.

Ether is a COLD climate last resort.

Some form of warming of the intake air is preferable A burning rag close to the intake is effective (Which is effectivel what flame starts, such as Thermostarts, do .But a Thermostart needs a battery suppy!)

Boiling water poured over the intake ducting can work well.

Catch 22 is how you boil the water; not an electric kettle in every case! .Ditto for hair driers and fan heaters

Good use for solid fuel of some sort, a small gas or kerosene blowlamp.

Howard

[Andrew TinsleyParticipant @andrewtinsley63637]

Hello Howard,

The magic oil is simply something like SAE 40. There is a small vertical cylinder with a cap, near the valve lifter,which you fill with maybe a couple of cc of oil. . Using the valve lifter, you then slowly crank up the engine to the best speed you can manage and drop the valve lifter and off she goes.

This cold start solution is built into the engine by Petter and its use is explained in the manual. I am not sure how or why it works, but it is a very effective cold start device.

Regards,

Andrew.

[Andrew TinsleyParticipant @andrewtinsley63637]

Hello Howard,

The magic oil is simply something like SAE 40. There is a small vertical cylinder with a cap, near the valve lifter,which you fill with maybe a couple of cc of oil. . Using the valve lifter, you then slowly crank up the engine to the best speed you can manage and drop the valve lifter and off she goes.

This cold start solution is built into the engine by Petter and its use is explained in the manual. I am not sure how or why it works, but it is a very effective cold start device.

Regards,

Andrew.

[oldveloParticipant @oldvelo]

Many years ago I was operating a Caterpillar D4 Crawler Tractor for a contractor who insisted on using heating diesel oil only. The motor always started easily and no running problems.

[HopperParticipant @hopper]

I'm with SOD in his earlier post. For an emergency generator that is hardly ever run, I would pay for proper diesel fuel for it. Not as if you are driving it thousands of miles a year and need to save money like a diesel car etc.

The thing about emergency equipment is the first priority is that it is there and working in an emergency. Jiggered up generator from duff fuel is not what you want.

The other factor is that emergency gens spend long periods of not being used, so corrosion and gumming up over time can be a factor. Good quality fuel might help your pump and injectors stay rust free and gum/gel free.

It's worth starting it up once a month and running it until hot for this reason too.

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