Series IIA Diesel has issues

[Aaron IIA]

I have just rebuilt my 2.25L diesel engine, and now it has developed a mysterious problem. The engine will start and run fine, (after the usual glow time when cold) but after about three minutes (just as the temperature gauge is starting to move) the engine develops a bit of a knock and puffs out large amounts of oil based smoke. It appears to be coming from only one cylinder judging by the regular puffing nature of the smoke. This all dissappears and behaves as normal after about a further three minutes.

My thoughts on the issue so far:
Engine is cold and runs normally.
Engine warms up a bit, to a temperature where non-vapourised oil can burn, engine runs partially on oil.
After a while oil is burnt out, operation returns to normal.

During the rebuild, I did replace the valve stem seals. They are the O-ring type. I did not measure the valve to valve guide tolerance, but the valves are not wobbly in the guides, and a small amount of compression can be felt when the valve stem is thrust up the guide with a finger blocking the other end. This would tend to indicate that the tolerance is reasonable.

Where can the oil be leaking from? The new stem seals were tested on the stems - they wiped the stems perfectly clean from oil in the first pass. Is it possible that the seals are marginally too small, and that oil is leaking between the seal and the valve guide? I purchased the seals from a reputable Land Rover parts dealer in Adelaide, who deals in Series parts. One would therefore assume that the seals are correct.

The valve guides are an interferance fit within the head. Is it possible for oil to leak between the head and the guide?

All help and suggestions will be appreciated.
Aaron.

[Blknight.aus]

does it do it only from cold?

does it do it more or less when your over running (engine braking) the engine?

how is your crank case ventilation setup on that engine?

hows it go under load?(and does the smoke get worse?)

Which air filter have you got? (oil bath or paper element?)

to work out which cylinder is doing it get it started and as soon as it starts puffing the wierdo smoke crack off the injecter unions one at a time (tighten them up after each one and cover with a rag to prevent fuel spray

if you can answer those questions then we're on the way to an answer.

it could be a handful of things starting with a compression ring not sealing and vaproising enough oil to be drawn into the combustion process via the crankcase ventilation to cause the smoke, to an oil ring sticking and not scraping the bore enough with the resultant oil causing the smoke.

if youve got an oil bath air filter you might be drawing something up out of that (and thats on the way to a runaway)


If it is burning oil in any of those ways you need to investigate it and recitfy imediately, while the 2.25 struggles to turn over on one pot when its cold if you get 2 or more going they can run away when hot... doesnt happen often as you can usually just dump the clutch in 4th with the brakes up hard to stop them but imagine if youd just walked away from it for a couple of minutes and it all turnes to pears.

[Rad97]

Sounds like one of your valves is starting to stick!!

or if pushrod operated this could be riding slightly.

[Aaron IIA]

It only does it from cold or when left for a period of time. It didn't do it after standing for one hour, but it did do it after standing for four hours.

I try to wait for it to stop oil burning before driving off, as I would get pulled over for creating a smoke screen, so I don't know what would happen in over run. When I put a load on the engine (ride the clutch in fourth with the brakes on) it goes down a bit but comes back when the load is removed. It gets worse when revs are increased with no load.

This engine has the old style open vent on the oil filler, so no crankcase pressure could develop. It does not breathe out of here like it did before the rebuild. The rocker cover cap has a pipe that is directed into the inlet manifold.

I have an oilbath air cleaner

I just spoke with a diesel mechanic friend on the telephone and he suggested that it might be the breather line from the rocker cover to the inlet manifold. This enters the end of the manifold at number four cylinder, hence the one cylinder knock as most of the oil would be drawn into the first available cylinder. We thought that the problem has arissen only after the rebuild, as during the rebuilding process, I restored proper pressure-fed lubrication to the rocker shaft which was missing before. This has resulted in much more oil being available and thrown around than in the past. More oil would be flung around, drawn up the cap and into the manifold through the breather line. Now that he has told me this, I can remember there being a slight amount of oil weaping from the join in the breather line where there was no weap before the rebuild.

Probable diagnosis:
More oil is available after repair, and is flung anround and suspended in the air, resulting in much more oil fumes being drawn through the breather line and into the inlet manifold.

I will test for this by disconnecting the breather line from the inlet manifold. Long term solution will be to manufacture a baffle to put below the rocket cover cap, and repack the cap with finer gauze to capture any oil and drain it back into the sump.

Please stay tuned, as I will let you know how it went, and if not successful ask for more suggestions.
Aaron.

[Blknight.aus]

if its not the breather line I have an alternative that leans towards an injector not being set up correctly.

to solve the breather line the best thing Ive done is inserted a fuel filter from what I think was a datsun, one of those plastic jobbies that has the outlet pointing stright out from the center along the axis and the inlet pointing out along the radius. that will fill with the oil and then when you shut down it will flow back into the engine.

Onto the possable injector theory, assuming that you have good cold compression on all pots

hows it idle before it puffs smoke?

is the idle improving when it is puffing smoke?

if its idling rough to start with but gets better you have an injector thats needling the fuel in instead of spraying it or is dribbling while its cold.

for a very short time and for diagnostic reason only remove the exhaust and look at what comes out FFS wear earmuffs.

[Aaron IIA]

Injectors and pump were professionally rebuilt about 5000 miles ago.

The engine will start, run and idle perfectly well from cold. Im guessing that it is the breather line thing.

When I first rebuilt the engine a month ago, I first started it up without any manifolds on. I did this so that I could see that all cylinders were exhausting evenly. They were. If the breather line does not fix it, I will pull the manifolds off to see which cylinder is smoking and causing the problem.
Aaron.

[UncleHo]

G'day Aaron 11A :)

I take it this is a 2 1/4 litre 3 bearing Diesel:), this motor's rocker gear is fed by an external nickol plated brass pipe with 2 banjo ends, this pipe is of approx 1/16 in bore, it feeds a metered amount of oil to the rocker shafts which in turn drains back into the sump through the pushrod holes also lubricating the roller rocker cam followers, IF, you have replaced this thin pipe/tube with one of large diameter, you are grossly over lubricating the rocker shafts and filling the head and valve gear with oil, it then has no option other than spill down the valve stems, hence causing excess smoke and the potential for motor destroying run-on:(

cheers

[Aaron IIA]

Problem solved.

I pulled the breather line from the end of the inlet manifold. It was full of liquid oil. The gauze in the rocker cover cap was absolutely soaking with oil. I removed the breather line and blocked the port in the manifold. From what I can remember, the adaptor in the end of the manifold that accepts the breather line can be removed and replaced by a welch plug the same size as the big ones in the side of the block. I then replaced the rocker cover cap with a petrol engine version, which is just vented to the atmosphere.

The engine is an early 2.25L three main bearing diesel. Early engines have O-ring valve stem seals (replaced with new ones, so I don't think it is leaking here) and tall injectors that are held in via a clamping bar across the top.

I mentioned in an earlier post that I had to repair the oil pressure feed to the head. I am still using the original oil pipe with the two banjos between the block and the head. What I modified was the block which holds the rocker shaft. Through this the oil passes from the head to the rocker shaft and so forth. The holes between the head and the rocker shaft block did not line up. I ground a small channel sideways on the bottom face of the rocker shaft block, to allow the oil to travel through. Did I do something wrong here? Is this making too much oil spray around in the rocker box? Without this modification, I could not see how oil was supposed to get to the rocker shaft. I assumed that the rocker train had come from a different year head, and this was why they did not perfectly line up. I have pictures which illustrate this, but I don't know how to put them into the posting.

To replace the breather lines to how they are meant to be, should I put a baffle underneath the rocker cover cap, to try and stop too much oil from being flung up into the breather line? Or have I made too much oil available in the valve area? Without doing the modification to the block that holds the rocker shaft, no oil at all was seen to be lubricating the rockers, pushrod ends or valve tops.
Aaron.

[isuzurover]

2.25 diesels have a reputation for breathing fairly heavily from the crankcase. Since yours is a new engine, it may take a while for the rings to bed in and the blowby to reduce.

Mine is a late model 2.25D (1979). It has no crank breather, and the rocker breather feeds into the air intake. When I first installed it as a rebuilt short motor, I installed a catch can to collect the blowby oil until the rings had bedded in. Since then I have done about 40-50k miles on the engine with no problems.

Your blowby problem may be made worse by the larger oil-feed pipe someone mentioned?

The LR breather is very low-tech and it is easy to make a better one (that will capture more oil and drain better) - but it should be sufficient.