step by step 2.5NA Rebuild thread (picture heavy)

[samc88]

I know I have another rebuild thread but thats more a collection of random photos

As most know, there is also a 90 on the go in our garage which is my brothers and the time has come for an engine rebuild. (Yes that project is still on the go just havent updated it for ages)

Stage 1: Getting the engine ready to lift onto the engine stand

Before doing anything, mark up the clutch and the flywheel so you know which way it goes when re-fitting. It makes life much easier if there is a chance of different hole centres in the clutch - just something I learnt through my own experience in work. The first thing to take off will be the clutch assembly



As the engine spins when you try and crack open a bolt, the proper timing pin was placed into the flywheel to hold it in position to stop the engine turning. (you could also either have a socket on the crank pulley or jam the ring gear if starter is removed)



The 6 retaining bolts were then removed using a 13mm socket





Once the assembly was removed, the bolts were put back in place so we dont lose them.



The flywheel bolts were removed using a 22mm socket on air driven impact gun, note the big retaining plate/ washer behind the bolts along with the dowel meaning the flywheel can only go back on one way





Revealing a rather oily flywheel housing, comfirming my suspicion that the rear crank seal is passing oil



Before taking the housing off, the starter motor was removed using 17mm socket and spanner. The earth bolt for the cable from the block to the motor is removed with a 13mm socket.





Next the flywheel housing itself is taken off, again with 17mm socket. There are 6 bolts inside the housing and 2 above. These 2 bolts have a bracket on them to hold wiring. These are also longer than the other 6



Its all pretty oily



Ready for lifting tomorrow evening



Tools needed:
Clutch assembly - 13mm socket
Flywheel - 22mm socket
Starter motor to engine block earth bolt - 13mm socket
Starter motor - 17mm socket and spanner
Flywheel housing - 17mm socket

 

[jamesmartin]

its not a good idea to use timing pin to lock engine for bolt removal

 

[samc88]

I wouldnt use it for crank bolt but worked well for the others. Also with an impact gun i dont think it puts much turning force on the flywheel anyway

Also when rebuilding the steyr engines in the marines boats in work we use timing pins to lock it

 

[Flossie]

Clutch cover bolts whip out easy enough by shock then I use a couple of bolts and a bar to hold the flywheel when cracking the flywheel bolts.
Whip the sump off and a block of wood to jam the crank for the damper bolt.
I'd get a box of latex gloves anorl, makes life nicer and pleases health and safety bods.
Got a very good FIP for one of them if you need it?
Change the core plugs or at least the rear one cos its a pain to do if they fail later, its cheap and easy and you can clean the water galleries somewhat too.

 

[Mick Guilbert]

Looks good

 

[zeaphod]

Always look forward to a good rebuild thread - looking good so far!

 

[samc88]

Stage 2: Removing the cylinder head

More progress, the engine stand was still set up for my 2.5N/a when that was on the stand which made life simpler. (Needs turning round in the photo)



Next up is to remove the breather pipes. These werent standard jubilees on this one, instead they were 6mm hex



The pipe going to the filler cap is held in place with this bracket which is removed with a 10mm socket/ spanner





Once these were removed, it was time to remove the rocker cover nuts with a 13mm socket. The rear one holds the other breather hose in place, and the middle one has the bracket on it for the heater pipes and filler cap breather hose





Rocker cover should then lift off. If its stuck a tap with a mallet usually frees it





Next step was the exhaust and inlet manifold which are removed using a 13mm socket on an extension bar



The image below shows the clamps on the top and just nuts at the bottom



Next up was the thermostat housing. This is removed through using a 10mm socket on the three bolts on top. These are very long and thin so if they're corroded then they may snap, luckily these came out easily







Then it was the turn of the injectors, first the pipes were removed







For the injectors, the spill rail was first removed using a 10mm socket to remove the banjo bolts. Next a 13mm socket was used to remove the two injector bolts. To get the injectors out the bore, a brass drift was used on the underside to knock them up gently, then a pry bar was used to lever them out being careful not to damage anything and being careful that it doesnt fly out the bore and land on the floor.



My brother has since taken his injectors to college to test, all are fine cracking off slightly above 135 bar but one has a little injector dribble so will be having a look at that later on

Next job was to move the rear lifting bracket out of the way so as to gain access to the banjo bolt for the head oil feed. This was done with a 10mm socket.



Next an 8mm socket was used to remove glow plug wiring



Then the oil feed pipe was removed using a 19mm socket on the 2 banjo bolts, one in the head and one in the block





The glow plugs were then taken out with a 13mm dep socket and strung together with the wiring, at least now we cant misplace anything



Next the 13mm bolts holding the rocker cover to the head are removed (the smaller more gold looking bolts seen in this pic)



Once this was removed, the pushrods were taken out and placed into cardboard in order numbered 1 - 8. It is important not to get these mixed up



Once everything is off, the head bolts can be slackened off evenly going by the book to get the order for bolt removal



Can then be lifted off, ready to be serviced later, the hotspots have some large cracks going through them and theres a lot of crap in the water jacket

 

[zeaphod]

Great quality pictures and thread - thanks. I note your crankcase breather is quite different from my 1985 model - I just have one vent from the rocker cover into the intake manifold. Any idea on the age of this engine?

 

[samc88]

Great quality pictures and thread - thanks. I note your crankcase breather is quite different from my 1985 model - I just have one vent from the rocker cover into the intake manifold. Any idea on the age of this engine?

1986, mines also an earlier one from 84/ early 85 with the single breather.

Not sure if the double set up was wanted by the military or just a general improvement by land rover to cure the heavy breathing issue

 

[jamesmartin]

1986, mines also an earlier one from 84/ early 85 with the single breather.

Not sure if the double set up was wanted by the military or just a general improvement by land rover to cure the heavy breathing issue

was for the military
yours is a turbo diesel block

 

[samc88]

was for the military
yours is a turbo diesel block

Was it common for NAs to use turbo blocks from factory? No record of engine change in our paperwork post MoD and didnt think they used the turbo diesel. Also the pump is standard dps off a 12j

 

[jamesmartin]

Was it common for NAs to use turbo blocks?

only later when they thought it prudent to supply one block to do all the 4 cylinder engines, you can see by the bungs lhs of block for turbo feed and lower one turbo drain, td blocks use different main bearings stc3395 (rtc4783),compared to original na block rtc2992

 

[samc88]

only later when they thought it prudent to supply one block to do all the 4 cylinder engines, you can see by the bungs lhs of block for turbo feed and lower one turbo drain, td blocks use different main bearings stc3395 (rtc4783),compared to original na block rtc2992

Okay thanks James very helpful I did notice the extra bungs. Are pistons and big ends still the same?
Also id imagine the numbers to be stamped on the bearings so id know if they were undersize?

 

[jamesmartin]

everything else is std 2.5na,bearings and pistons should have size stamped on

 

[samc88]

everything else is std 2.5na,bearings and pistons should have size stamped on

Thanks james for the info, very helpful