If you run a 2.25 (3 main bearing) or a 2.3 (5 main bearing) Diesel engine Series and your reading this then your more than likely having trouble with a smoky exhaust. A heavily smoking Series diesel is probably one of the most talked about subjects regarding this vehicle as its a common problem and one that can be the most difficult and confusing to rectify. Having experienced this problem myself I’d thought I would share my findings and try to explain some of the mystery's of reducing exhaust smoke to an acceptable level. First things first though, this engine dates back to the 1950’s in the form of the 2 litre diesel engine. Then in 1958 it became a 2.25 petrol engine which in turn went onto being the 2.25 diesel in 1962. This 3 bearing variant in 1962 became the ‘10J’ engine which continued right up until 1980 after which a 5 bearing variant was
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produced. So if you think about it the engine design is about 60 years old ! 60 years ago engine designers were concerned about reliability, power, fuel consumption to a certain degree but certainly not emissions. In fact they had probably never heard of the word until they started to export the Series Land Rover to places such as New Zealand and America. So what we need to achieve is an ‘acceptable’ amount of smoke as compared to a modern eurobox TDI engine which is virtually nil. The 10J engine principles are they same as a modern engine in that it sucks air in, which is then compressed before diesel is injected into the now hot compressed air. This causes the fuel to burn which produces power to push the piston down the bore. This motion is transferred to the crank, then via the transmission and onto the driving wheels. What we need to do is ensure that the engine is running as efficiently as possible to help reduce the amount of excess exhaust produced. Now this engine will always produce some smoke, that is the design of the engine so you must accept that it will never be a completely smoke free experience. However the 4 things which will probably be of concern to you are 1) Efficient running to increase MPG, 2) The environment (good luck with that one) 3) To reduce emissions to enable it to pass an MOT or equivalent. (Note if yours is a pre 1980 model then it doesn’t require a probe up the exhaust as its only a visual test). 4) To prevent the embarrassment of producing a smoke screen.
For starters the engine must be in reasonable good health. That means not using excessive oil, water or diesel fuel. Its difficult to say how much it should be using as every vehicle is driven different, with different loads and on different roads. But if your engine has started to suddenly use any of these in vast quantities then its pretty safe to say something is amiss. Its difficult to do an assessment on your own engine as you probably don’t want to admit its knackered. My own engine would start on the button (even after sitting for weeks) had excellent oil pressure but would drink oil as quick as I could put it in and would smoke like a destroyer on full chat. The exhaust smoke can tell a lot about the state of an engine however.
VISUAL EXHAUST STATE WHEN ENGINE UP TO TEMPERATURE:
The above is only a guide as there can be other factors which affect the exhaust smoke. One of these is the butterfly valve (if you have a servo fitted) shown in the picture on the right. This is designed so that when you lift off the throttle and apply the brake, the flap closes and produces a vacuum that feeds the servo to assist the brakes. If this isn’t adjusted correctly it can starve the engine of air causing problems during combustion. Take the inlet pipe off so you have the view in the photo and gently press the throttle pedal. Watch the flap slowly open and then look at the throttle assembly on the Injector pump. The butterfly valve should be opening just before the Injector pump throttle has started to move. This is to allow extra air into the cylinders before extra Diesel is injected such as when pulling away from a standstill. This helps prevent excess smoke being emitted as you pull away.
If this is ok then continue to push the throttle to the floor. The butterfly valve should now be horizontal to the body of the unit so that an unrestricted air flow can enter the engine. If adjustment is necessary then this is done by adjusting the arms on the throttle control rod.
Firstly make sure that the valve is fully closed when the throttle is released. If not release the nut/bolt circled in the photo on the left and move the arm until the valve is closed. Tighten the nut/bolt and move onto the Injector pump end.
Try the test as described above to see if the valve opens slightly before the pump does. If it doesn’t then release the nut/bolt as circled in the photo on the right and push the arm down so there is a bit of slack at the end of the outer cable. Tighten the nut/bolt and check the operation. If there is to much valve movement before the pump moves (thus stopping the valve from fully opening on full throttle) then reduce the amount of slack at the end of the outer cable. This is easier to do than to explain! Once your happy everything is working correctly you may find your brakes work a bit better too!
If your exhaust smoke isn’t too bad (not blocking the sun out) then maybe a slight tweek of the timing may be all that’s needed. To make small adjustments to the timing then it will be necessary to move the injector pump one way or the other to alter at which point the fuel is in injected. This may also be necessary to fine tune your timing after setting it up as described HERE. To do this release the three bolts securing the Injector pump to the block and undo the 4 Injector pipe unions at the top of the pump. Don’t remove them completely but just undo them by a couple of turns. This allows the pipes to move as you turn the Injector pump. Do NOT do this with the engine running……! The arrow on the pump body shows which way the pump turns when the engine is running. So to
advance the timing you need to turn the pump against the arrow (clockwise) and to retard the the timing you turn with the arrow (anti clockwise). Observe the mark on the pump base in relation to the pointer and only move it literally 1mm at a time. It goes like this, release 3 bolts on pump body and release 4 pipe unions at the top. Move pump 1mm which either way is required then tighten up all bolts/pipe unions. Start engine and check running. If further adjustment is needed then release bolts/pipe unions turn another mm and do everything up again and check. It seems a bit of a ball ache and it is but its the only way to achieve what you want. If you find the pump wont turn then it will probably be stuck on the gasket underneath it. Rock the pump gently to free it and try to move it. If no joy then use a rubber oil filter strap wrench wrapped around the top to give you a bit
Arrow on pump body
of extra leverage. Failing that a rag rolled up, wrapped round and the ends twisted tight may be a good alternative to the strap wrench. Do not use a screw driver or bar shoved through the top or against the pipes or brackets as leverage as damage to the pump could result. I have never found it necessary to bleed the pump afterwards as long as the pipe unions are only loosened and not removed. If you find that you cannot move the pump in the direction you want (usually clockwise to advance it) because the studs at the base of the pump are at the end of the elongated hole. Then the only option is to renew the timing chain/gear as described HERE. You may read on the Internet that you can file the hole bigger (yours may already have been done) so that the pump can turn, but to be honest its not the best way as the valve timing will also be out. If by turning the pump both ways has no effect on the smoke then chances are the timing chain and components are worn or have gone slack.
Pipe unions (x4)
bolts around base(x3)
Pointer and mark on base
Wrap strap wrench around here
Of course you may have a mixture of smoke colours indicating more than one problem,. You will need to work on one area at a time to eliminate the issues. As a guide (but not set in stone) Blue smoke is burning oil and is usually an expensive and more involved fix. Black smoke can be expensive but not to difficult to solve. Whitish smoke is usually the more straight forward to solve and can be the cheaper fix of the three. The problem with a smoking engine is that many factors can cause it. Its not like an oil seal leaking where you can see it straight away and know what to do to fix it. It comes down to a bit of guess work, perseverance and a bit of luck.