I recently dropped a valve in my 2.5TD. After buying a replacement second-hand short engine and a remanufactured cylinder head, I have at last got it back together. I had considerable trouble with the clutch after the slave popped out when separating the gearbox. It took me a complete weekend to finally get the clutch working again. Then, on starting the engine it ran like a bag of nails.
After re-checking the timing, I next removed the intake manifold (another virtually impossible feat). I discovered that 2 of the little valve to rocker cradles had jumped out of position. Could this have been because the hydraulic tappets were slow to fill with oil and therefore take up the clearance? Anyway, I popped these back into position and put everything back together (virtually another weekend). Once again, it refused to run properly with starting difficulty, rough running with clouds of smoke. Next, I put a length of clear tubing in the diesel feed line and immediately discovered that the pump was drawing in great gobs of air. This, I traced to the usual splitting of the feed pipe in the inaccessible lower region behind the engine, drivers side. I corrected this and still found air in the line, this time, after the filter. Took the filter apart and on investigation found that as the central bolt was being tightened, the threaded portion of the casting had split and the bowel could now not be tightened enough without the risk of breaking this part away completely. This, of course rendered the filter housing so much scrap. After fitting a replacement, at last no bubbles. Fingers crossed. Car started, not as easily as I would have wished and ran OK -no excessive smoke, smooth and all seemed well. Took for a road test and all seemed well at first so gradually increased throttle openings to check out fully. Pulling nicely, revs going up, turbo working nicely, but, on releasing the throttle and going to idle, the roughness returned with again, clouds of smoke behind the car.
I managed to nurse the car and switched off. I while later, it again started, a little reluctantly, and ran fine again. It seems that as it warms up it is OK unless I give it some revs, say above 3,500 and let the throttle return to idle, the roughness and smoke returns. I am hoping that someone here may help. My line of thinking is now that maybe it has something to do with the Exhaust Gas Re-circulating system. It seems, at the moment that everything I look at has is the root of the problem until I fix that and discover it was not that after all. I would be thankful for any thoughts, suggestions etc. This is starting to get to me.

Hi rosspa,

Having been there myself I need to ask you to describe accurately what you mean by "I checked the timing". As a rare occurrence the Haynes book of lies describes the timing process very well.

If there's a trick its correctly identifying the correct hole on the flywheel into which you insert the locking pin via the lug on the engine block. There are six threaded holes which can be seen from the back side of the flywheel. These are the six securing bolts for the clutch spring plate. Next to one of the holes there's a plain hole the same size as the others with no threads. It is about 1" or 25mm away from one of the threaded holes. Since the engine is running the timing can't be far away, so line up the cam and injection pump and look in the vicinity of the lug sticking out from the engine block. Please check very carefully that you are using the correct hole on the flywheel. Using the wrong but next closest hole will give you the symptoms you describe. I say this from bitter and embarrassing experience.

I am presuming you know the remainder of the timing process but if you have the time you could describe in detail how you are going about it.

cheers

noz

Noz. Thank you so much, You were spot on regarding timing mistake. I can’t believe that I made this mistake. Luckily, I still had the old block, so could work out exactly what had happened. What had confused me is that I carefully marked the original timing before I swopped over the blocks. What I didn’t realise is that I had already made the mistake of using the wrong timing hole at this stage. Therefore I repeated the error when swopping parts and setting timing up on replacement block/head. It really is one for wider awareness as it is so easy to do. Thanks again, engine is now running beautifully.

As I know to my own cost it is a very easy mistake to make. I'm just glad your car is running correctly now.

Cheers

noz

Hi,

I checked mine using the pin point on the back of the block -


Steve.

Have another problem now! low water light came on. On checking, I find I have a header tank full of oil!! I assume that this must be the water filled oil cooler under the filter leaking oil into the water? I am ready to give up. Though I must say that the car owes me nothing and has been brilliant over the 6 years and near 100000 mile that I have done since buying it.

Don't give up yet! The engine will run at a reasonably steady temperature with the oil cooler omitted from the circuit and replaced with a piece of suitable piping -Copper or rubber. A new cooler will set you back at least £250 unless you can land on one from a scrapper!.

If you don't want to run without one then you can run with one from another engine type. Whilst the 2.5's oil cooler is much larger than most it does seem to work fine with a different (smaller) one in the same way that it is works fine without one for those who have tried.

Mine has been running with an oil cooler from some unknown other scrap engine (unknown as the garage had it on their parts shelves for so long that they had forgotten what it came from). It is a more standard cooler and so it much smaller, but it just needed a bit of extra pipe length (some normal 15mm copper pipe did the job) to connect it all up. The engine never runs over temp and has been running fine like that for over a year and I do push it hard at times, but don't tow.

The other thing to do is make sure you clean out the coolant afterwards. Draining and re-filling doesn't seem to do much to remove the oil. Overfilling the expansion bottle gets more out, but it still leaves a lot in the system. My indy put a cleaner fluid in there and I ran on that for a while, and it is now spotless - though it did help me find the pre-existing pinhole leak in the front rad quite quickly You will probably need a new cap for the expansion bottle as the oil attacks that very fast.