2.25L Diesel Engines
Original Author: Mike Rooth (M.J.Rooth@lut.ac.uk)
Land Rover's first diesel was the 2 litre,now almost extinct.This was introduced as a result of customer demand coming from fleet owners with diesel fleets,(trucks,buses etc) where the Land Rover was the only vehicle they had which had to be trundled down to the nearest filling station. The engine was noisy,and due to Land Rover's peculiar policy of providing "equal capacity" engines (2litre petrol/2 litre diesel)rather than "equal power" engines made the vehicle slower than its petrol counterpart.The unit was not overly successful.The writer knows of at least one owner who never went out without a plastic bag full of injector pipes in the back,due to the tendency of these pipes to split. Anyone offered a vehicle with the 2litre diesel should think long and hard,because spares are now almost non-existant.The last reference to a 2 litre diesel the writer saw was a magazine ad which listed the engine as an unfinished project.The reason for sale was given as "fed up with it".
Contrary to the beliefs of some,the 2.25 diesel,updated from the 2litre,is a competent and hardworking power plant.It is also,in passing,part of the reason why the 2.25 petrol is so overbuilt,since the petrol engine uses parts common to the diesel. Again,the odd size for size policy makes a vehicle with this engine slower than its petrol driven brother,but that notwithstanding,it is a well made and durable engine.An indication of this can be gained from the fact that the line can be traced directly from the original 2litre,to 2.25,then 2.5 naturally aspirated (fitted in the early 90 and 110 vehicles)on to the 2.5 turbo,which was finally replaced by the Tdi. Maintenance and overhaul are no more difficult than on the 2.25 petrol,whilst fuel consumption figures should be much better,the order of 28MPG being quoted as normal for an engine in good condition. Spares are slightly more expensive than for the petrol version.It is essential to change the oil at,or more often than,the stated intervals,for a long life.This,however,applies to any diesel engine. Injectors and the distributor pump are not owner serviceable.
Excessive exhaust smoke can usually be laid at the door of injectors or distributor pump.If the owner is certain that these items are in good order and in the case of the distributor pump,properly timed,it is as well to check that the valves are correctly gapped,and correctly timed.This assuming,of course,that the bores/valve guides are reasonable.
The 2.25 diesel as standard has series wired heater plugs. Consequently,when one fails,no heater plugs at all is the result,making the engine virtually impossible to start,particularly from cold. A firm,Dieseglow,makes a replacement set of parallel wired plugs,which in addition to the eliminating the problem described above,has made the plugs much more robust,having a "bulb" type element,rather than the fragile twisted wire element of the originals. They are very little more expensive than a replacement set of series wired plugs, and the price(currently around 25 pounds a set),includes the replacement wiring. The original resistor is retained.In the writers opinion they are well worth having.They are widely available in the UK.
Series 11 and 11A diesels originally had two 6volt batteries,one under the passenger(LH) seat,and one under the bonnet at the right hand side at the front.It is worthwhile to eliminate this arrangement,since in the UK at least, suitable batteries are not as readily available as 12v ones.The S111 has one large 12v battery under the bonnet,and it is this arrangement which is perhaps easiest to copy.The size required is around 96Ah.WARNING:These batteries are *heavy*.In the UK they come with carrying handles,and even so,it is no mean feat to lift one in and out over the wing.If at all in doubt,it is better to make the operation a two person job,rather than risk injury,or possibly more important,dropping the battery!
Fuel additives are increasingly widely available,all claiming such benefits as to make one think that the engine should be *creating* fuel,rather than using it.The writer has tried two.It should be noted here that the engine has good compression,slightly suspect valve timing,and injectors which had not been out of the engine for about five years.The first was Wynn's,a one-shot put it all in the tank affair.As far as I could make out it made not a bit of difference. The smoke level remained the same,starting was no easier,running no smoother. The second was an American product,made by Red Line,and called 85 Plus Diesel Fuel Additive.This is added a "shot" at a time,(the bottle is calibrated) every ten gallons worth.24 hours after adding the first shot the engine was noticeably smoother and quieter. Inside the first week I found I was getting a mile or two per hour more from the engine for the same throttle opening. Presumably had I not used the extra speed I could have traded it off for increased economy. Starting became easier,and smoke levels were reduced,but not eliminated . Unfortunately,the additive is not readily available in the UK, being currently imported by a one man business,so when I ran out,I discontinued its use,so am unable to comment on the long term effects of using it. However, initial impressions were favourable.For those interested,the address of the Manufacturer is:
Red Line Synthetic Oil Corp
3450 Pacheco Blvd,Martinez,CA 94553,USA.
The 2.25 valve timing is chain driven,and should last a good long time. However,the chain can stretch given time,leading to less than ideal valve events.For those with the money,an English company has produced a set of gears,and replacement timing case,which will eliminate the effects of chain stretch for good.The company is Zeus Design Patents.The modification is available for all 2.25 engines,petrol and diesel,and 2.5 likewise.It is of even greater benefit to 2.5 users,because it replaces the troublesome timing belt used on these engines,failure of which can prove expensive,if not disastrous. Gear's are also available for 200,and 300Tdi engines.The kit is not cheap,over 200 pounds at time of writing (18/1/96).One owner with a 2.5 naturally aspirated engine had such a kit fitted,and the resultant reduction in emissions caused the relevant meter to refuse to register any at all! Which led the garage owner to call out the engineer,thinking the equipment had failed.It had not!The company's address,for those with the necessary depth of pocket is:
Zeus Design Patents
8,Devon Units, Budlake Road,
Marsh Barton, Exeter, Devon,EX2 8PY England.
Running the Engine
As with all diesels,starting must take place with a wide open throttle. Indeed the original Owners Manual specifies this. Since diesels require a copious amount of air,particular attention should be paid to keeping the air filter clean,and the airways unobstructed. S11,11A,and 111 models have a hand throttle,which can be used to raise the tickover on cold mornings until the engine has warmed through.On unmade tracks, the engine will drive the vehicle at tickover,at remarkably low RPM's. Engine braking is extremely good,and useful. For those used to petrol engines,the S11 & 11A Engine Stop Pull knob takes a little getting used to.Note:the engine must be stopped first,*before* switching off the electrics. Particularly if the vehicle is alternator fitted. The S111 has its engine stop on the steering column.The only other difference is the low fuel warning light,which starts to flash with fuel surge at about a quarter tankful,and glows steadily when about two gallons are left. Running out of fuel in a series machine is not to be recommended,since the fuel system will require priming by hand before the engine will run. It is advisable to keep plenty of fuel in the tank in winter,to combat possible waxing,although modern fuel has anti-waxing agents added, or should have.Even so,two gallons in a ten gallon tank will wax up quite readily,even in conditions attainable in the UK.Be warned! Finally,the diesel vehicle has 11 leaf front springs,as against 9 leaf on the petrol model,to compensate for the extra weight of the engine.It is worthwhile counting the leaves on the front when examining the vehicle prior to purchase.It may not always have been a diesel,or may have had the wrong springs installed.Rear springs are the same on both models.
As stated earlier,maintenance and overhaul are really no more difficult than for the petrol model. Series 11 and 11A diesels have a "four stud" exhaust manifold.That is to say that the exhaust front pipe is fastened to the manifold via a four stud flange.This arrangement is very similar to the S1 petrol,inasmuch as the front pipe is horizontal and at right angles to the chassis centre line.The pipe exits the engine bay via the LH wing.This makes changing the exhaust on these models a very simple job,since the vehicle does not need jacking up.The front pipe is merely unbolted from the manifold and the centre pipe,and withdrawn from under the wing. Replacement,as they say, is the reverse of assembly.S111 models have the three stud manifold,with a vertical front pipe,and have to be jacked up to remove the exhaust. The starter on the diesel models is a large(and expensive) pre-engaged type. The owner should ensure that electrical connections are clean and tight, particularly on the starter solenoid,and the starter motor yoke should have a good,clean earth(ground) to the chassis.One of the longitudinal through bolts should terminate with a nut,and it is this that should be earthed to the chassis.Also,when converting from the two battery configuration to the single large battery,it is *essential* to use the correct low voltage cable for the main battery leads.The previous owner of the writer's S11A had used 440V cable for this purpose,with the result that a week into ownership the writer,when attempting to start the engine one morning,looked up and was puzzled to see what he thought was fog,but which he quickly realized was smoke.The resultant fire eventually cost a new starter motor,and a proper set of main battery leads.It has to be realized that with a 23:1 compression ratio,the starting currents are little short of murderous. Further to the subject of starting,do *not* use products such as "Easy Start". The original Owners Handbook specifically warns against this,pointing out that the excessive head pressures generated will severely damage the engine. The fuel filter should be renewed regularly,it collects a surprising amount of water,which can freeze and clog the system.Even unfrozen,water has no business in the fuel system.The writer was advised by people whose advice he can trust,not to bother draining the water out of the fuel filter via the wing nut under the housing.It is said to cause more trouble than it solves, possibly by introducing air into the fuel system.As a general rule,if you touch it,replace it,then prime the fuel system. SWB diesels can develop an uncomfortable "pitching" motion.To some degree, they will always pitch a little,due to the short wheelbase and stiff suspension, but this should never reach the neck snapping stage.The symptoms are simply that under acceleration,or deceleration the vehicle will behave,and ride,normally. Similarly,ascending or descending hills.But on the level,when traveling at a constant speed,the slightest undulation in the road will set it off pitching, just as though there were no shock absorbers present. The fault lies in the throttle return spring on the distributor pump.If this is weak,or broken,this is the effect produced. Fortunately,the spring is only 25p and takes two minutes to fit.The complete cure is to replace the throttle linkage with cable,but this is both more involved,and more expensive.It is assumed that the LWB models are also prone to this effect,but are perhaps more restrained about it due to the extra weight and the longer wheelbase.
If it is necessary to remove the cylinder head,do NOT be tempted to have it skimmed.This should not,in any event,be necessary,since the head is a large and rigid iron casting,and not,to the writers knowledge,unduly given to warping. Skimming the head will(not may,but will) result in the aluminum"hot spots" recessed and pegged into the head falling out in service.When this occurs,the engine will be a write off.Head overhaul is a specialist job,and must be treated as such.This danger cannot be over emphasized. The cylinder head,when returned to the engine*must* be torqued down twice. When the writer rebuilt his engine he bought a head gasket advertised as being such that it only needed torquing down once. However,the firm from which it was bought said that they used this gasket,but even so,they torqued their heads down twice. Start the engine and run it for about twenty minutes at fast idle until warm,shut down,remove the injectors,torque again,replace injectors, bleed fuel system,and run.Yes,it *is* a fiddle,and yes,it *is* worth it. When replacing pistons,the new pistons may arrive with a ring fitted in the skirt groove.This is wrong. Remove the skirt ring,it is not only not required, it can cause rapid damage.The skirt groove is not a ring groove,but an oil return groove. The rocker cover on the diesel engine has a flat gasket face,and does not trap the gasket. Consequently,when tightening the rocker cover,the gasket easily slips out causing a messy oil leak. There are two solutions. There is available(readily nowadays) a gasket with one side self adhesive.The user merely peels off the protective paper on the "glue" side,and sticks it to the rocker cover,having first cleaned the mating face. Failing this,impact adhesive can be used to stick the gasket on,but cleaning the old adhesive off when changing the gasket may be more trouble.The cover can be tightened without any fear of slippage. The standard 2.25 diesel manifold gasket is not the strongest in the world. When the writer last replaced his,the advice given;and taken;was to fit the 2.5 gasket instead.This is visibly stronger,and is still in place.
The reader of the Land Rover mailing list may be confused by the reference to "Oily Wadders" with respect to diesel engines,and their drivers.The writer has to plead guilty to the introduction of this term.For those interested,the term is derived from the early days of Destroyer development. Early ships were coal fired,and involved their crews in the "interesting" exercise called Coaling Ship,which reputedly covered everything and everyone in coal dust.The introduction of oil fired destroyers ridded the ship's company of this chore,much to the disgust of those serving in the older vessels. These disgruntled matelots therefore invented the derogatory term "Oily Wads" for the newer ships,and Oily Wadders were those serving in them. Since the bunker fuel is akin to diesel,the writer thought it appropriate.The situations are somewhat similar,too,since neither the sailors nor the diesel drivers were,or are,in the least upset by it!