Smoking rebuilt Perkins Diesel help needed!!!

[artfulltune]

I have 2 Perkins Range 4's, 354 c.i., 6 cylinder naturals that also had developed smoking and throwing a nasty sheen on the water. Rebuilt the injectors, clean with new nozzles. I spoke with the mechanic doing the work regarding your problem and he said worn bores need to be re-sleeved on most Perkins. Could be your issue?

[MHW382]

Sounds like timing problem. Over the past 9 years I have had the unfortunate experience of having 3 injector pump repairs. After each one The engine smoked (white) upon startup with a strong diesel odor. On each repair I have had to argue with the mechanic that the problem was timing, not some other factor. Ultimately they adjusted the timing and the white smoke immediately disappeared. To me, the timing would be the easiest and quickest step to try.

[Sojourner]

Update: So I talked to a trusted owner friend who has lived here for a long time with 3 big boats, ie he has a good mechanic, whom he asked to come over straight away. Dude came over and looked at it, stethoscoped it with a dowel, checked for contamination in oil/radiator/under caps etc... He thinks it's gonna be a top end issue, valves or valve seals. Wants to pull the top off and take it to some pro rebuilder. Seems adamant it is not unburnt diesel.

Should I force him to start with less invasive things like pulling/testing injectors and compression before ripping into the motor? I dont think it is a timing issue cause the engine is reassembled and set back exactly at the marks. But still smells like unburnt diesel to me.

Do blown valve seals produce both unburnt diesel and oil? Seems like they could....

[SwellGuy]

Originally Posted by Diesel3446

In your case you may have to rotate about 1/16" more than the mark alignment, because it sounds like it is quite retarded.

woah woah woah no need to get nasty

[Sailmonkey]

Originally Posted by Sojourner

Update: So I talked to a trusted owner friend who has lived here for a long time with 3 big boats, ie he has a good mechanic, whom he asked to come over straight away. Dude came over and looked at it, stethoscoped it with a dowel, checked for contamination in oil/radiator/under caps etc... He thinks it's gonna be a top end issue, valves or valve seals. Wants to pull the top off and take it to some pro rebuilder. Seems adamant it is not unburnt diesel.



Should I force him to start with less invasive things like pulling/testing injectors and compression before ripping into the motor? I dont think it is a timing issue cause the engine is reassembled and set back exactly at the marks. But still smells like unburnt diesel to me.



Do blown valve seals produce both unburnt diesel and oil? Seems like they could....

Leaky valve seats lower compression and cause unburnt fuel to be exhausted, and worn valve seals/guides cause oil to enter the exhaust stream as well as be sucked into the engine for ignition.

Lots of blue smoke from oil.

[a64pilot]

Originally Posted by Sojourner

Do blown valve seals produce both unburnt diesel and oil? Seems like they could....

Worn or dried valve guide seals would not cause un burned Diesel, they would account for smoke on start up that goes completely away in a minute or so though. What happens is oil leaks past them on shutdown so that it burns off pretty quickly after start up.
Some motors don’t even have valve guide seals, usually smaller more primitive motors, they just smoke on start up.

A type of compression test called a leak down test will tell you if your motor has any excess compression leakage, and more importantly tell you exactly where.
It puts air under pressure into the cylinder when it’s at top dead center.
If you hear leaking in the intake manifold, you have a leaking intake valve, same for exhaust, if you hear the air leaking from the valve cover when you remove the cap, you have leaking rings.

I would find someone that can do a leak down test if possible cause that will tell the tale without disassembly.

[skipperpete]

Hi sojourner. Ideally you should be getting the engine rebuilder to solve the smoke/diesel on the water problem but the idea of getting the trusted independent mechanic is also a good one. Your Perkins Prima is a difficult engine to deal with due to the overhead cam and timing belt setup and if the belt is even just a tiny bit out, all the settings are wrong .... cam timing as well as injection. Also the valve adjustment procedure is quite a challenge and requires the fitting of an adjusting spacer for each valve to increase or decrease the clearance between it and the camshaft so really a job for a mechanic since the cam has to be removed to install the adjusting spacers.
Good luck with the diagnosis and repair, let us all know if you solve the problem.. and how.

[Diesel3446]

As I said previously, the injection pump timing is late, retarded. (Wihte/gray smoke, especially at cold start, and spitting raw fuel) This often happens when CAV pumps are removed and reinstalled. THE INJECTION PUMP NEEDS TO BE ROTATED. Look at the top of the mounting flange on the injection pump and the corresponding engine mounting surface. There should be 2 marks, one on the engine and one on the injection pump. They should be aligned. The injection pump needs to be rotated in the OPPOSITE direction of rotation in your case. Look at the blue tag on the side of the injection pump, the injection pump needs to rotate in the OPPOSITE of the arrow on the tag. Loosen the 3 injection pump mounting nuts slightly, and rotate the pump, ENGINE NOT RUNNING, until the marks align. In your case you may have to rotate about 1/16" more than the mark alignment, because it sounds like it is quite retarded. The injection pump can be timed by lining up the engine timing marks with the engines #1 piston on compression stroke and aligning the timing marks under the tear drop shaped cover on the injection pump. SEE MANUAL.

[Diesel3446]

Your engine seems to have the timing quite retarded. I have, many times, had to do this to get an engine, most often a Perkins, to stop white smoking. To rotate the injection pump as much as you will have to, you will most likely need to loose, by 1/2 turn, the high pressure lines on the injection pump so that it will rotate more easily. Tell the mechanic to try it WITH THE ENGINE NOT RUNNING, he will see that it improved, and will need to continue in small increments, 1/16", until the smoke stops. OR get the manual and set the timing that way.

[Diesel3446]

If this engine starts pretty much immediately when cold, having not run for 10 hours or so, ...then there is not a compression issue. The less invasive check, as Martin and others have said, is to check & adjust the injection pump timing. I get that it was set to the marks... Been there done that. If it walks like a duck, and quacks like a duck... it is the timing.

[shakey doug]

Old copper injector seal joint can be left in bottom of hole, new joint fitted to replacement injector then fitted= 2 joints in place = white/ grey smoke.

[Sojourner]

UPDATE:

The original guys came back and did a compression test and pulled the head. The pic is below. The compression numbers were within spec and near each other: 23, 22, 22, 21

The cylinder heads and valves look fine except that they are all uniformly black, instead of nice brown, and the exhaust pipe coming out of the head is coated in fine black oil. As is the turbo. So oil is entering the process upstream of the block? Because I can't imagine all valves being equally bad or poorly reassembled surely....? And compression as well was decent and uniform.

Can the fuel pump on these old diesels introduce oil to burn? I was told in that case there would be diesel in the oil, not vice versa, but I don't know these engines well yet....

Any ideas?

[Sailmonkey]

The only common device upstream of the intake that contains oil is the turbo. If the seals in the Turbo are shot, it will inject oil into the intake.

[DaveSIM]

Originally Posted by DaveSIM

When did you have the high pressure diesel pump overhauled?? Looking at the age of it I would say the seals are gone and timing off. New diesel does not have Sulphur for lubrication in it so wrecks the old seals. Did the injectors meet the specs for opening and closing pressures? Sounds to me like both pump and injectors need checking again. This happened to me a while ago and I had the same symptoms. Take the injectors to the shop first and they can check them while you wait. If they are the problem OK. If not then take the pump in for checks. Are you getting any diesel in the lubricating oil? A bad pump will leak into the crankcase. Check the dipstick. Good luck and let me know what you find! Dave

QUOTE DavesIM The black residue that is oily is probably diesel mixed with the soot and coating everything. Have you been loosing oil from the crankcase? All previous comments say no. You would get blue smoke if it is burning oil that leaks from the turbo. Your problem is the injectors and high pressure diesel pump. Too much fuel and poor combustion. Compression ratio is good so all points to the fuel system. Take the injectors to a good diesel fuel pump and injector shop and have them checked to specifications for pressure open and close and jet. If they are good (which I don't believe) then check the high pressure pump for timing. If the timing is off then the combustion is incomplete and you'll get unburnt fuel and soot. Let me know what happens. Thx DavesIM

[rbk]

Originally Posted by Sailmonkey

The only common device upstream of the intake that contains oil is the turbo. If the seals in the Turbo are shot, it will inject oil into the intake.

Is there a vent from the timing cover/crank to the intake on this engine? The new compression in the crank may be feeding the oil into the intake? I remember on some Perkins there is a piece of gauze or wire mesh in the vent tubes to reduce the amount of oil passed to the intake, just taking shots in the dark here.