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2.5 N/A timing belt replacement.

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This is the method used to replace the timing belt on a rather nice ex-military 90.

Parts needed to do this job properly are timing belt (Dayco), tensioner, water pump gasket, timing cover gasket, crankshaft front oil seal, and timing cover dust seal.

These engines are real workhorses, and seem to go on forever. Ruined by Land Rover, when they then fitted a turbo in the hope of a cheap upgrade. This engine had been stood for a year, but still starts on the button and pulls like a train.

The noticeable thibg about this engine when you open the bonnet is the huge cowling that takes up 1/3 of the room.


The cowling is held to the radiator by these 4 little screws along the top - flimsy, awkward things they are and wouldn't budge.


The big jubilee clip was the next option, and the clever thing about these is that you only need to turn them a few times, and the threaded screw will then flip outwards, and you can then slide plenty of the band through.


Detach the lower radiator hose and drain the system.


The forward part of the cowling is steel, and is held to the engine in three places, and mounted on small vibration rubbers.



Once the three nuts are removed, the cowling can be flattened and removed from between the radiator and fan.

The viscous fan is left hand thread, so while the fan belt is holding the pulley for you, undo the 32mm nut behind the fan with a water pump spanner - clockwise.


Also slacken the 4 x 13mm bolts that hold the pulley to the water pump body.


Looks like somebody didn't do a very good job!


Slacken the alternator, and oush it towards the engine and remove the fan belt, water pump pulley, and the belt tensioner - note the spacer tube on the adjuster bolt.


These three bolts are very prone to snapping - they pass through the water pump, timing case, and into the engine block. They rust and seize solid, and it's almost impossible to stop one from shearing off if it's stuck in the thread through corrosion. Judging by the looks of this - someone has had problems in the past. One bolt (at the top) is the correct 13mm M8, the right hand lower is 17mm M10, and the left hand is 14mm M10.

The pump body was threaded as well as the timing case, so it look like someone drilled and tapped the whole lot without taking the pump off first. There were no leaks, so I supposed its good enough. Right swine to take the pump off though.


The gasket is in there somewhere - buried in a whole load of gasket goo.


Crank bolt next - 42mm on this one - later bolts were smaller.


Easiest, but dangerous way to undo the bolt is with the assistance of the starter motor.

41mm impact socket on a breaker bar - make sure it's a good fit on the crank bolt.


The end of the breaker bar goes under the chassis on the drivers side (turn the crank until the bar is snug against the underside of the chassis rail.


Next, unplug the fuel cut off switch wire - the engine musn't start, and removal of the wire will prevent that from happeneing. The idea is to crank the engine on the starter a few turns to undo the bolt.


Close the bonnet down, and then briefly flick the starter switch - the energy of the starter will 'crack' the thread, and the bolt will them come undone.

With any luck the crank pulley will then slide off. Sometimes these are stuck pretty solid, and a puller is then needed.


there are supposed to be two bolts either side of the wading plug hole - both are missing. The oil is from the crank seal being loose/worn.


Undo all the timing cover bolts and keep them in order (make a bolt tidy from a bit of cardboard)

The timing cover will then lift off, revealing the timing belt, tensioner, crank sprocket, cam sprocket, and injector pump sprocket. (dunno why there's two yellow dots on each sprocket)


Replace the crank bolt and rotate the engine until all timing marks are in line with thier respective pointers.

Left hand sprocket is the injector pump - there is an 'F' mark and a line to indicate that position, and then the next tooth is the timing pip, which you will use when replacing the timing belt, and aligns with a cast arrow in the rear timing case.


The cam sprocket has just the one timing mark, and aligns with an arrow that is cast in the timing cover rear face.


Finally the crank sprocket, the timing mark on that should be at 12 'o' clock position - once again in line with an arrow cast in the rear of the timing case.


The tensioner is held in place by two 13mm nyloc nuts - remove these and the tensioner can be lifted out and discarded, the timing belt will have gone slack with the tension released, discard it.


The crank front oil seal was very loose, and the oil in this picture is a result of that. Normally the seal is a tight fit, and requires some careful leverage to remove.


Everything needs to be cleaned - the rust staining on the nose of the crank is removed with 1200 wet/dry with oil.


The timing belt is fitted, then hook the tensioner behind it and tension correctly. Make sure the timing marks are still where they should be. Rotate the the crankshaft clockwise 2-turns - this equates to one turn of the canshaft and injector pump sprockets.


put anew dust seal in the front timing cover.


Re-check the timing marks and tensioner, then re-assemble the timing cover and the rest of the components. I used a new gasket on the water pump, but as the bolts were a bit of a mess, I also used RTV sealant. That's it really, make sure the crank bolt is correctly tightened.

A couple of things I noticed while doing this job -

The air filter was sitting in a pool of oil, the filter was pretty bad, but apart from this, the engine runs very well - no smoke or horrible noises, and it starts on the button.

Perhaps it's just overdue for a service.



The bowl of the filter housing has some cracks in. Not seen that before - vibration?? sounded and felt ok to me.


Les. :)

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