Uneven engine operation.
 

Hi all!
I overhauled the D24T.
-put new sleeves, squandered
-installed new Kolbenschmidt pistons
-installed new valves, ground them
After repair, the motor, during operation, sways at a certain speed.

I want to record a video of his work. Post it here so we can diagnose.

But I don't speak English and I won't be able to comment on the video
Attachment 1914

Welcome!

Looks like very nice work you did on the engine.

Uneven engine speed is often caused by air getting into the fuel system. Are there any places where air could be getting sucked in, for example near the fuel filter? Is the fuel filter installed tight and does not have a doubled up inner O-ring causing it to not seat the outer O-ring? Can you see any air bubbles moving in the translucent hose from the fuel filter mount up to the injection pump?

Do you smell diesel fuel under the hood anywhere? Any difficulty starting the engine if the car has been parked facing uphill? Those are also common signs of air leaking into the system.

Does the uneven operation happen all the time or just when the engine is cold?

If you are sure there is no air getting in, then the next place to look would probably be to double check injection timing and some other possibilities.

Thank you very much for your quick response and detailed tips.
Yes it was not easy! :)

I couldn't take a video or photo today. Because we are at war.
Tomorrow I will definitely record a video of how the motor works and show you. Then you will understand what is the reason and you can tell me.
Thanks again!
See you tomorrow...
Attachment 1915

Attachment 1916

Hello.:)
Managed to make a video. But after uploading to YouTube, the quality was lost.

I look forward to your comments after viewing.

If something needs to be changed or added, please let me know.

https://youtu.be/BIL1OrFaprQ

Attachment 1917 Attachment 1918 Attachment 1919

I answer your questions
The fuel system is completely sealed. Was checked by me from the tank to the fuel filter.

The engine starts great. Starting is independent of temperature or vehicle position.

- all the time.

-yes i'm sure of it

I look forward to further advice from you.

Very nice looking car in your photos. And yes, hope you and your family are in a safe place from the violence in Ukraine. We in the US have been paying close attention to the war there and are inspired by your country's efforts.

After watching the video, it's hard to tell exactly what the engine is doing but I think I can see and hear the uneven operation you are describing. It sounds to me like the injection pump timing may be set incorrectly.

What was the timing value (mm) that you set the injection pump to?

And, did you remember to disconnect the cold start device cable when setting the timing? Easy to forget this, and if you do, it results in retarded injection timing that leads to issues like what you are seeing.

It sounds like it starts right away so I agree you can probably rule out air in the fuel. Looks like you did very nice and clean work and I am sure it will run great once you find the issue. :)

Unfortunately, there are no safe places in Ukraine now.
Thank you! Your country helps us very well.
I have tried different options for setting the injection timing. 0.8; 0.85; 0.9; 0.95mm
With a smaller value, the motor runs softer. With a larger value - works hard.
However - at any value, the motor staggers at about 1400 rpm.
I turn it off during setup.
Yes, the engine starts immediately(right away). Both hot and cold.

Perhaps somewhere there is a video on how this motor should work correctly ... I have nothing to compare with.

Watched the video, sounds/looks like an intermittent miss to me. The engine shakes more than it should, especially at idle. Have you tried cracking one injector line at a time to see if you can narrow it down to a certain cylinder that isn't firing correctly? Could have an injector nozzle hanging up. I'd also run a piece of clear hose for the fuel return from the pump/injectors and see if you're getting any air bubbles. You can have air pushed into the injection pump from a fualty injector which will really screw up how it runs... Ask me how I know! If you don't see any air, but can narrow it down to a particular cylinder, I'd do a leak down test of that cylinder, and depending on your findings, I'd swap injectors from one cylinder to another and see if you mis-fire follows the injector.

Jason

Thank you Jason for your input. I am very glad for your help.
I will answer your questions
Yes, I did. Result: at the moment of releasing the nut of each nozzle, the engine runs on five cylinders. It starts shaking even harder.
Unable to identify a cylinder that is not performing well.
I did. There is no air in the return pipe.
All injectors were tested on the stand. The high pressure pump is also tuned.

Do you have access to another known good injection pump? I think at this point I would swap it for another pne and try it.

Jason

Unfortunately, in this situation, it is not possible to install another fuel pump.
Do you still think it's the pump?
In the same way, the motor worked with the previous pump. before pump repair. Repair of the pump did not give any result.

Well if it's not the pump it would have to be a mechanical problem with the engine, however the miss sounds to be intermittent. If there was a cylinder down on compression due to a ring issue or valve not sealing, the low compression would cause poor running consistently which typically will diminish as rpm increases as there is less time for the engine to loose compression. Have you done a leak down test? Another possible way to help with diagnosis would be to pull the injectors and inspect the tips of the nozzles. If there is a cylinder that is struggling to fire correctly the nozzle will be either moist with fuel or carbon'd up more than the other nozzles. Something to look at anyway. If you still can't narrow it down to a particular cylinder via injector inspection or a leak down test, I would suspect the pump and try swapping with another one.

Jason

Thanks for helping!!! Thanks to your advice, it is easier for me to endure the war. You give advice. I check them. It takes away from the war.
v8volvo - this applies to you too.

Yes. I did a test. The difference between the cylinders is 0.5 kgf / cm2
Attachment 1922Attachment 1921 (Instrument readings are not correct)
That's the difficulty, that soot on nozzles and washers is the same. Even after a long trip.
It may be necessary to do so:rolleyes:


I have a question:
what if the engine has a different degree of compression in the cylinders? If anyone cylinder protrudes from the block less than the others. A leak test won't show this.
Can I try to reduce the thickness of the washers under the injectors?

There is no adjustment for injector height, just the heat shield. But you would be able to detect difference in compression via a compression test.

Jason

Compression test:

Cold........Hot

1) 25,5....27
2) 25 ......25
3) 25 ......26
4) 25,5 ...26,5
5) 25,5....25,5
6) 25 ......26,5

The readings of the device may differ from the actual ones.
The device shows values less than another. Add 1.5 to the data.

I'm used to psi here but I'm assuming those values are bar? Looks pretty consistent across the board. Not much left to do other than swap to another pump.. I'm fresh out of suggestions.

Jason

Yeah, I agree, it sounds like the only option left may be to try a different known good pump.

Or another option that could be easier if another known good pump is not easily found: If you have a Bosch fuel system rebuilder shop that is operating near you, then you might also be able to bring them the injection pump and have them run it on their test bench. If there is any issue with the pump they would be able to see it when they run their tests, and then probably would be able to rebuild the pump and fix whatever might be wrong. These old VE pumps are still used in many pieces of equipment and vehicles all over the world so any good diesel injection shop with the Bosch sign out front should be experienced and certified to work on them.

One other test that could be worth a try: if you are able to get an infrared thermometer, you could check the temperature of the exhaust manifold at the port for each cylinder. If it has a weak/skipping cylinder (due to any issue -- fuel pump or injector, or something in the base engine) then you might be able to see that the problem cylinder is running cooler than the others.

The compression readings look nice and the engine sounds good in the video other than the driveability problem.... so it hopefully should be a very nice runner once this issue is figured out. :)

Yes.

v8volvo and Jason!
Thank you for your advice. When the opportunity arises, I will try.

My recent 940s 1995 purchase runs like this ......lumpy on warm tick over. Cold and hot start works perfectly

I changed the fuel filter and clogged air filter but still lumpy

Will investigate further after I change the cam belt

Is the crank bolt 27mm and the torque setting 300 lbs ??

I don't have the tool for locking the crank pulley, but will figure something out. Also need to find a bigger torque wrench lol

Too little info to make a diagnosis, if that's what you are looking for. What is the history? Did it come on immediately one day? Have you checked the IP timing? Valve clearances? What is the power? Smoke? How many mileage?

More like 350 lb-ft. You may be a mechanical genius but most "figure something out" with a monster torque wrench solutions don't work out successfully in the end.

Forum members have made satisfactory facsimilies of the Volvo special tools, you can search here and find them. Involves welding and fabbing skills.

Indeed, I am starting to think this engine is more trouble than it's worth. A nice merc 300 straight 6 would be a lot less trouble. Just changing the rocker cover gasket is a bleeding nightmare to change, especially if the nuts on the injector side are rusty and seized. It is probably just a matter of time before it starts leaking again on the exhaust side

I took the cambelt cover off to have a look at the belt as I am still in contemplation mode regarding the belt change, as I need so many specialist tools before attempting the replacement. So with the slack on the adjusting pulley side, I slackened the adjuster bolt and let the adjuster take up any slack, which it did. What a difference that made, no stuttering when pulling away or when changing up the box and a little less lumpy on tick over.

The air intake pipe that goes over the rocker cover has evidence of oil in it so suggests the engine is breathing heavy and at 165K I am thinking it is in need of a rebuild ......but is it worth it ??

Is that strong evidence for a rebuild? Where did you get this information?

What is your oil consumption?

What are the compression numbers?

With proper maintenance these engines can run strong for several thousand miles. Most early death examples are from botched maintenance practices (mainly insufficient tightening the crank pulley) causing catastrophic piston/valve interference.

How so? You mean the OM603? They are far more expensive to maintain and get parts for and harder to work on. Cylinder heads fail all the time, flawed castings. Trap oxidizers always plugging, injection pump delivery valves constantly leaking. The D24T is a much better engine with far fewer inherent issues, speaking here from firsthand experience working on both day in and day out for years back when I was an employee in a professional shop.

14 nuts from my memory, maybe 16... Easy access with a regular 10mm socket on all of them, are we missing something here? :cool: The updated style rubber one piece gasket is not common for leaking and is even reusable. Once you get one of those in there, it's set for good.

Total number of special tools is something on the order of a half dozen depending on what you are doing and needing exactly. Pretty standard for any diesel engine, it's the nature of the beast. You are absolutely correct that you do need the right tools.... but it's usually not a deal breaker. Very easy and inexpensive to improvise with slightly modified 2.5L 5cyl TDI cambelt tool set also, which is widely available for example on UK Ebay.

Glad to hear the engine is running better :cool:, but am I reading you right that you made adjustments to cam and IP timing by altering belt tension, without using the tools to verify timing? It's always nice to know what timing setting you are running -- might be valuable to check it now. If changing the timing improved it this much, then there could still be further room for improvement, if for example the last fellow who did the belts failed to get timing adjusted correctly (perhaps hence your improvement from playing with timing). In other words you may still have not seen the best of it yet.

Like on any other diesel engine, the crankcase vent tube will -- and should -- have some oil vapor in it. That's the reason it is there. :p Evidence of some oil presence in the CCV tube is NOT an indication of poor engine health by any means. Especially not on an engine that runs well, starts easily, and doesn't consume excessive amounts of oil. Those factors, and a compression test, are your real indicators of engine health. As ngoma already pointed out.

From everything I am hearing so far, you have a nice car and engine that could use a little attention but sounds like it's in sound basic condition and is most certainly worth the effort to keep it up. :cool:

Welcome to the board!

100% agree with v8volvo and Ngoma on this. As I understand from the owners forums you have been looking for a D24T for some time and now you have one it seems you're not overly impressed. The real questions to ask yourself is what were you expecting? And do you want to keep it?
I have to admit I'm not a mechanic by trade, this is a hobby for me and I'm assuming it is for you too. The D24 is a great engine when maintained correctly and the performance potential is there at a fraction of the price of modern diesels due to its simplicity.
I hope you choose to stick at it, the guys on here currently and in the past have shown passion and enthusiasm for something that most have forgotten and that is another reason I like this engine so much, the community is small but it's still there.
Hope you have happy spannering in the future :D

I just wrote a post and pressed send and needed to log back in again then lost the post

Need to remember to copy the post before sending it .....doh !

Shorter version .........thanks for your replies and your optimism much appreciated. Obviously this engine is very different to other diesels that I have owned. It is not just a case of oil and filter changes and away you go. The car is in excellent condition, inside and out, a 1995 940S TD, so in the right hands would be a keeper for sure, of that there is no doubt. I love the way the car handles, it turns like my Peugeot 309 GLD, very quickly. It is a smooth ride and very reassuring, no knocks or bangs.

On a run down to Pitlochry yesterday ......2hrs each way, I could feel the engine holding back/missing intermittently, when on a constant throttle. When accelerating it seemed to pull ok. It hasn't done this before, even with a very dirty/blocked air filter. The engine still starts well on the cold start and when hot and idles ok, not as lumpy as before the slack was taken up in the cam belt. So as has been said, the valve timing and IP timing needs to be checked and adjusted before I get too despondent.

I need to find a dial gauge and cam lock plate. For changing the cam belt I need to make up the tool for the crank pulley .......is that a 27mm bolt ? Instead of using the tool to lock the crank pulley is it possible to lock the flywheel instead ?

Here is a useful vid, but lacks certain details
https://www.youtube.com/watch?v=Bp0UxiNM3SA

Just ordered a dial gauge and camshaft locking plate kit, hopefully should fit

https://www.ebay.co.uk/itm/265142893171

Hi. The timing tools you bought look good hopefully they fit okay. The sudden missing and holding itself back is probably fuel related, perhaps if you have a fresh fuel filter it is a bad injector or maybe a sticky delivery valve on the pump, more likely an injector though. One inexpensive thing you could try before spending silly money is get a new fuel filter or empty your existing one if it's almost new, fill it with a diesel injector cleaner or Automatic transmission fluid (ATF) screw it back on. Run her up for a good while and that should clear any small dirt or debris if that's what's causing the problem. Be warned some people don't like using ATF to do this, in my experience it works better than any crap injector cleaner you can buy. Also do you have the green book service manual for this engine? It may help you out a lot.
Cheers
Tristan

Hi, I have changed the filter and emptied the old one into a bucket and found some debris in the fuel. Running some cleaner through is a good idea. I agree on the injectors and currently bidding on an injection nozzle pop tester on ebay to refurbish the injectors

Once I have rounded up all the appropriate tools, parts and info I will get the timing and fuel system sorted. No green book as yet

Bought a spare deep 27mm impact socket to either fabricate the crankshaft tool or to use with a nobar break back torque wrench

Also picked up some domed head 6mm nuts and spring washers today for the rocker cover. The standard nuts allowed the thread above the nuts to rust through, snapping the top off two studs, as the shoulder below turns against the rocker cover. Luckily the stud left under the rocker cover is loose and easily taken out once the cover is removed. The studs can now be secured in the head with locktite. The domed nuts will protect the threads from now on

Ideal. Sounds like you're getting some bits sorted. There was a reasonably priced bound copy of the Green book on eBay I'll link it here https://www.ebay.co.uk/itm/354252013...mis&media=COPY
If you want a PDF copy instead of buying one I can get you one but it's for the D24 NA engine. All the procedures are pretty much the same it just doesn't include anything about the turbos and some of the figures for emissions and injector pop pressures etc will be different. I personally prefer having a hard copy as page turning is much easier. :D

I've just bought all the stuff for reconditioning my injectors, so keep us updated to see how yours are going.

That's a good idea about the rocker cover nuts. I've never had trouble with them seizing on mine but clearly it can happen. Being mechanical lifters on mine it comes off fairly regularly so I guess that's why it's not a problem.

Many thanks for the link much appreciated, thats a 100% must have. So, there can be no excuses when armed with the correct data, will get the other half to purchase one tonight as it is her account ;-)

I just received the timing kit set and looks perfect and includes the camshaft plate and IP locking plug.

Ordered another rocker cover gasket ....this time the same as the original, a one piece rubber gasket

Just going to do a pre- mot check as it is due on the 22nd. I have a sympathetic local mot tester who loves old motors. He was well pleased with our 1989 Peugeot 309 GLD and went sailing through. Finger crossed