D24T.com  

Go Back   D24T.com > Technical Discussion Area > Diesel Engine and Drivetrain

Reply
 
Thread Tools Display Modes
  #1  
Old 05-09-2022, 12:53 PM
Echo1975 Echo1975 is offline
Junior Member
 
Join Date: Dec 2021
Location: Finland
Vehicle: Volvo 240
Posts: 25
Default Engine running bad after rebuild

Here we go again

In my previous posts I have explained how I cracked my D24 head and have started to look for a new one.

During this time I found a head and had it machined and I lapped the valves. Adjusted the valves to pretty much exactly to what the book says. I got new stem seals, installed a new metal head gasket and tightened it correctly following the instructions it came with.

But... After all this I got the car running again but it runs like shit and barely stays running without the glow plugs even with full operating temperature and has white smoke when idling even at full operating temp. When at low throttle the engine sputters and jerks so much that driving normally is impossible. Also getting it started is a chore. It starts up and revs up and stalls multiple times before getting it barely to run with the throttle.

I have verified that the valve timing is correct and I have matched the mark on the injection pump as good as I could. The head gasket doesn't seem to be leaking. Liquids are not mixing. Engine feels like it has very good compression when turning by hand. It feels like the engine has been cammed because of how much the rpms jump around constantly at idle.

I'm so lost with this again. The only things I can imagine it being is the pump timing because why would only messing with the head affect how the car behaves under throttle. I tried it an hour ago and the engine doesn't have nearly as much power as it had before. The acceleration took over half as long to 60 mph as it had taken before.

When I looked at the pump timing mark, I am uncertain of it because it doesn't exactly match the mark on the pump frame but I can't get the marks to match any better. It looks like if I go a tooth further on the belt, it will just jump too much to the other side.

Also could 1 tooth off on the pump mess it all up so bad?

I really need some input on this.
Reply With Quote
  #2  
Old 05-10-2022, 08:12 AM
v8volvo v8volvo is offline
Supporting Member
 
Join Date: Jun 2009
Location: Montana, USA
Vehicle: '86 745, '83 764
Posts: 1,514
Default

Quote:
Originally Posted by Echo1975 View Post
I have verified that the valve timing is correct and I have matched the mark on the injection pump as good as I could. The head gasket doesn't seem to be leaking. Liquids are not mixing. Engine feels like it has very good compression when turning by hand. It feels like the engine has been cammed because of how much the rpms jump around constantly at idle.
When you say you verified valve timing, was that with the camshaft locking plate inserted and the rear cam gear removed?

Quote:
Originally Posted by Echo1975 View Post
I'm so lost with this again. The only things I can imagine it being is the pump timing because why would only messing with the head affect how the car behaves under throttle. I tried it an hour ago and the engine doesn't have nearly as much power as it had before. The acceleration took over half as long to 60 mph as it had taken before.
This sounds like textbook incorrect pump timing so I think you are correct about that. The good news is that it will be easy to fix -- you just need to get the right equipment and process. Very simple steps compared to the other major work you have already successfully done.

I would guess one of these two things has happened.
1) Pump is timed 180 degrees out from camshaft. Did you verify that the cam lobes for #1 cylinder are both pointing upward (#1 compression TDC) when the injection pump gear's timing is approaching the notch on the injection pump bracket? The engine will still run with timing 180 out but extremely poorly.
2) Timing is not 180 degrees out of phase, but is also not set correctly. See below.

Quote:
Originally Posted by Echo1975 View Post
When I looked at the pump timing mark, I am uncertain of it because it doesn't exactly match the mark on the pump frame but I can't get the marks to match any better. It looks like if I go a tooth further on the belt, it will just jump too much to the other side.
The way you get the marks to match better is with the timing process using special tools -- BUT at the same time, the marks don't really matter. They only are an extremely rough guide help you confirm that you are timing the pump to the correct cylinder, lining up to TDC. From there everything is done with fine adjustments using a dial indicator as shown in the factory service manual (or find youtube videos online like this one https://www.youtube.com/watch?v=LWyhxPM9TOE). Did you use that process?

It's not adjusted tooth by tooth -- that is much too large of an increment to achieve the needed precision.

Quote:
Originally Posted by Echo1975 View Post
Also could 1 tooth off on the pump mess it all up so bad?
A whole tooth???? Oh yeah, it sure could. Timing is required to be EXTREMELY exact on this engine, like on any diesel without computer control. Even a fraction of a tooth out of time will make it start/run poorly, and on many engines, a full tooth off will either make it not able to start (if retarded) or risk blowing headgasket or bending connecting rods (if advanced). This is why the timing on this engine is all done with taper or friction fit, no keyways, and why the timing process and tools are so sensitive. You can't just "line up the marks and go" like on a gas engine or computerized diesel. Visual timing just doesn't work here, you *have* to use the correct locking tool for cam timing and the dial indicator for pump timing, and go through the steps in exactly the right method and order.

The good news, again, is that as long as you have the necessary equipment and info, the process is easy and the engine will run perfectly afterwards.
__________________
86 745 D24T/ZF 345k lifted 2.5"
83 764 D24T/M46 155k
Reply With Quote
  #3  
Old 05-10-2022, 11:37 AM
ngoma ngoma is offline
Supporting Member
 
Join Date: Nov 2009
Posts: 1,166
Default

Quote:
Originally Posted by v8volvo View Post
The good news, again, is that as long as you have the necessary equipment and info, the process is easy and the engine will run perfectly afterwards.
I agree that optimism is warranted here but there is one other item that we need to verify: appropriate head gasket thickness. Unless the piston protrusion was checked and correct thickness head gasket installed the OP may still encounter hard starting, lackluster performance, and poor fuel economy even after (the probable) timing issues are rectified.
__________________
1985 744 gle d24t
1985 745 gle d24t
Reply With Quote
  #4  
Old 05-10-2022, 01:14 PM
Echo1975 Echo1975 is offline
Junior Member
 
Join Date: Dec 2021
Location: Finland
Vehicle: Volvo 240
Posts: 25
Default

Quote:
Originally Posted by v8volvo View Post
When you say you verified valve timing, was that with the camshaft locking plate inserted and the rear cam gear removed?



This sounds like textbook incorrect pump timing so I think you are correct about that. The good news is that it will be easy to fix -- you just need to get the right equipment and process. Very simple steps compared to the other major work you have already successfully done.

I would guess one of these two things has happened.
1) Pump is timed 180 degrees out from camshaft. Did you verify that the cam lobes for #1 cylinder are both pointing upward (#1 compression TDC) when the injection pump gear's timing is approaching the notch on the injection pump bracket? The engine will still run with timing 180 out but extremely poorly.
2) Timing is not 180 degrees out of phase, but is also not set correctly. See below.



The way you get the marks to match better is with the timing process using special tools -- BUT at the same time, the marks don't really matter. They only are an extremely rough guide help you confirm that you are timing the pump to the correct cylinder, lining up to TDC. From there everything is done with fine adjustments using a dial indicator as shown in the factory service manual (or find youtube videos online like this one https://www.youtube.com/watch?v=LWyhxPM9TOE). Did you use that process?

It's not adjusted tooth by tooth -- that is much too large of an increment to achieve the needed precision.



A whole tooth???? Oh yeah, it sure could. Timing is required to be EXTREMELY exact on this engine, like on any diesel without computer control. Even a fraction of a tooth out of time will make it start/run poorly, and on many engines, a full tooth off will either make it not able to start (if retarded) or risk blowing headgasket or bending connecting rods (if advanced). This is why the timing on this engine is all done with taper or friction fit, no keyways, and why the timing process and tools are so sensitive. You can't just "line up the marks and go" like on a gas engine or computerized diesel. Visual timing just doesn't work here, you *have* to use the correct locking tool for cam timing and the dial indicator for pump timing, and go through the steps in exactly the right method and order.

The good news, again, is that as long as you have the necessary equipment and info, the process is easy and the engine will run perfectly afterwards.
Turns out this is absolutely the way.

I didn't get the tools but did a way better job at the timing and the engine runs 5 times better atleast. It runs at a constant rpm and has good power. I need to fine tune the pump but would like to get the valve timing 100% correct beforehand and I am still unsure if it is since I didn't have the right tools.

So after today I have made some observations. The pump timing absolutely was the reason the engine ran so bad. I wish I could say the smoke is completely gone but no, it smokes white smoke when cold. The smoke also was reduced from filling the whole workshop with smoke to having some visible smoke.

Since adjusting the timing had such an improvement already, I hope fine tuning it will make it way better.

Thank you very much for your input on this. Got my hopes back up for this car.
Reply With Quote
  #5  
Old 05-10-2022, 01:18 PM
Echo1975 Echo1975 is offline
Junior Member
 
Join Date: Dec 2021
Location: Finland
Vehicle: Volvo 240
Posts: 25
Default

Quote:
Originally Posted by ngoma View Post
I agree that optimism is warranted here but there is one other item that we need to verify: appropriate head gasket thickness. Unless the piston protrusion was checked and correct thickness head gasket installed the OP may still encounter hard starting, lackluster performance, and poor fuel economy even after (the probable) timing issues are rectified.
I chose the new headgasket by the amount of notches the old one had.

measured the piston protrusion and it was in the accepted range for the head gasket manufacturer information
Reply With Quote
  #6  
Old 05-10-2022, 02:00 PM
v8volvo v8volvo is offline
Supporting Member
 
Join Date: Jun 2009
Location: Montana, USA
Vehicle: '86 745, '83 764
Posts: 1,514
Default

Great news.

Quote:
Originally Posted by Echo1975 View Post
I wish I could say the smoke is completely gone but no, it smokes white smoke when cold. The smoke also was reduced from filling the whole workshop with smoke to having some visible smoke.

Since adjusting the timing had such an improvement already, I hope fine tuning it will make it way better.
Yep it seems like you are definitely on the right track. Although you have already made a massive improvement by doing some timing adjustment, like you said, the timing is still probably not exactly right on, resulting in the excess smoke you are still seeing. But the improvement from your initial adjustments confirms the timing was the cause of the issue.

Once you have made the final cam and injection timing adjustments using the proper instruments, that should be further reduced and the engine should run at least as clean as it did before this work. Or possibly even better than that, depending on how accurately the timing had been set before by the previous fellow.
__________________
86 745 D24T/ZF 345k lifted 2.5"
83 764 D24T/M46 155k
Reply With Quote
  #7  
Old 05-13-2022, 01:47 AM
Echo1975 Echo1975 is offline
Junior Member
 
Join Date: Dec 2021
Location: Finland
Vehicle: Volvo 240
Posts: 25
Default

Quote:
Originally Posted by v8volvo View Post
Great news.



Yep it seems like you are definitely on the right track. Although you have already made a massive improvement by doing some timing adjustment, like you said, the timing is still probably not exactly right on, resulting in the excess smoke you are still seeing. But the improvement from your initial adjustments confirms the timing was the cause of the issue.

Once you have made the final cam and injection timing adjustments using the proper instruments, that should be further reduced and the engine should run at least as clean as it did before this work. Or possibly even better than that, depending on how accurately the timing had been set before by the previous fellow.

So I need to set this clear.

I have set the cam timing the way that cyl 1 has the cam lobes pointing up and in the rear there are 2 notches and I have aligned those with the head surface.

The cam timing could be a little bit wrong but I don't think that could effect the engine too much.

Also I didn't have the locking pin for the pump so I loosened the rear camshaft gear and held the pump in a position where the pump gear mark aligns with the mark on the pump frame, then tightened the camshaft gear which left the pump mark aligned with the pump frame mark.

When fine tuning the pump, is it normal that when starting to rotate engine counter clockwise the dial indicator number doesn't rise instantly after the 0 mark on flywheel.

I measured the pump timing and adjusted it and got the piston travel to 0.92mm. It was about 0.65. Although this has improved the engine, it still smokes a bit when hot.

Also I still keep having this issue where the car jerks with very little throttle. This can be seen by giving just a little throttle with the clutch pressed because the rpms go up and down constantly with little throttle.

I am currently thinking it could be air in the fuel system or a fault related to the pump shutoff solenoid but doubt this one but it has to be kept possibility.

I have tried it without the fuel filter and it runs the same without it so it's not about that. The pump pulls fuel very well from the tank.

I'm still kind of devastated by how the engine literally ran smoother with 5 cylinders before the rebuild. It has more power now but it runs kinda rough now.
Reply With Quote
  #8  
Old 05-13-2022, 11:57 AM
ngoma ngoma is offline
Supporting Member
 
Join Date: Nov 2009
Posts: 1,166
Default

Quote:
Originally Posted by Echo1975 View Post
...held the pump in a position where the pump gear mark aligns with the mark on the pump frame, then tightened the camshaft gear which left the pump mark aligned with the pump frame mark.
The IP position is not the way to set the IP timing. The marks cannot be used for anything but extremely rough guessing. In fact, we like to have the IP positioned rotated outward from the head, to make future replacing of the rear glowplugs easier.

Couple questions for you:

Quote:
Originally Posted by Echo1975 View Post
I have set the cam timing the way that cyl 1 has the cam lobes pointing up and in the rear there are 2 notches and I have aligned those with the head surface.
Did you use Volvo tool 5190 with a 0.2mm feeler gauge or similar or did you eyeball it?

Quote:
Originally Posted by Echo1975 View Post
I measured the pump timing and adjusted it and got the piston travel to 0.92mm. It was about 0.65. Although this has improved the engine, it still smokes a bit when hot.
0.92 is fine but did you measure this while the cold start device was deactivated?

Quote:
Originally Posted by Echo1975 View Post
I'm still kind of devastated by how the engine literally ran smoother with 5 cylinders before the rebuild. It has more power now but it runs kinda rough now.
Yes me too, it should only be running better. We need to go thru it methodically. It's really not that complicated but the process does require special tools and unorthodox procedures to guarantee success. Many many have tried to "cheat" and use commonly accepted mechanics practices instead and failed.
__________________
1985 744 gle d24t
1985 745 gle d24t
Reply With Quote
  #9  
Old 05-13-2022, 03:59 PM
Echo1975 Echo1975 is offline
Junior Member
 
Join Date: Dec 2021
Location: Finland
Vehicle: Volvo 240
Posts: 25
Default

Quote:
Originally Posted by ngoma View Post
The IP position is not the way to set the IP timing. The marks cannot be used for anything but extremely rough guessing. In fact, we like to have the IP positioned rotated outward from the head, to make future replacing of the rear glowplugs easier.

Couple questions for you:


Did you use Volvo tool 5190 with a 0.2mm feeler gauge or similar or did you eyeball it?


0.92 is fine but did you measure this while the cold start device was deactivated?


Yes me too, it should only be running better. We need to go thru it methodically. It's really not that complicated but the process does require special tools and unorthodox procedures to guarantee success. Many many have tried to "cheat" and use commonly accepted mechanics practices instead and failed.
I don't have any special tools except a dial indicator. I basically eyeballed the cam timing.


I had the cold start device in the hot position while setting the pump timing.

I am very lost with this one considering I don't understand how the pump timing works if what you people are saying is true.

If the marks align and the piston where you measure with the dial indicator displays a correct amount of travel, how can the timing be wrong and how do I set it in that case?

I have been driving for a few days now and the car has been working pretty good. There is still that problem where the car sputters a bit with low throttle.

I swear the car is slower than it used to be when it worked good but it could be because I had a 1.9 tdi while rebuilding the engine and I got used to that.
Reply With Quote
  #10  
Old 05-15-2022, 11:47 AM
v8volvo v8volvo is offline
Supporting Member
 
Join Date: Jun 2009
Location: Montana, USA
Vehicle: '86 745, '83 764
Posts: 1,514
Default

Quote:
Originally Posted by Echo1975 View Post
I am very lost with this one considering I don't understand how the pump timing works if what you people are saying is true.

If the marks align and the piston where you measure with the dial indicator displays a correct amount of travel, how can the timing be wrong and how do I set it in that case?
I don't think that method is necessarily wrong. I think your pump timing setting process should give a successful reading, assuming you are using the method of loosening the four fasteners holding the pump to its brackets and rotating the pump in order to get the desired reading on the dial indicator. Correct?

When saying this is not the way to do it, ngoma meant that this is not the "best/easiest" way -- it's easier/better to do using the 9995199 counterhold tool and rotating the cam sprocket rather than moving the pump. However, correct timing can be achieved using your method as long as you understand how to do it. It's just more labor intensive and can sometimes leave the pump in a resting position that obstructs access to #5 and #6 injectors and glow plugs (although on the NA engines without as tall of an IP, this too is less of a factor).

So, bottom line, your methodology of adjusting timing should not prevent you from getting a successful setting, as long as you are able to tolerate the extra effort versus our preferred method.

But there are still things that could be causing a problem. You asked,

Quote:
is it normal that when starting to rotate engine counter clockwise the dial indicator number doesn't rise instantly after the 0 mark on flywheel.
Not understanding this exactly. Why are you rotating counterclockwise (backwards from engine rotation)? I think it is true that if you go CCW, the reading would be falling as you pass through the zero mark and then not begin to rise again for several degrees. But you do the timing process in the CLOCKWISE direction, and in that direction the above is not true.

The way the timing *checking* process works is that you:
- disengage the cold start device so that it is resting in the hot position (sounds like you did this)
- install the dial indicator and its holder, then begin turning over the engine and adjusting the holder so that you achieve the correct ~2mm (at least 1mm) preload on the dial indicator AND have it zeroed successfully. it should return to the same zero point consistently each time the reading falls AND that zero point needs to be with preload so that you know it's zeroing on the low position of the pump plunger, NOT zeroing on the tool's own internal stop. Recognize that if you don't achieve these things then the dial indicator's readings are meaningless and could misinform you.
- then once you are sure you are set up correctly in terms of preload and zero point, continue to turn the engine over until the notch on the IP pulley begins to approach the marks on the pump case and bracket, indicating that your #1 cylinder's piston is on the approach to compression TDC
- when you see the dial indicator fall to zero one last time before #1 TDC, then start to climb again, now look into the bellhousing at the flywheel and slowly bring it up to the 0 mark. When it centers the 0 mark with the pointer in the bellhousing, look at the dial indicator. Whatever it says there is your correct timing reading.

NOTE that in this process, the dial indicator will begin to rise BEFORE the zero mark on the flywheel is reached. In fact the 0 mark on the flywheel is where you need to stop to take your reading, and by that point, the timing on the indicator should already be around 0.90-0.95mm.

If readings do not appear at the expected crank angles on the dial indicator, then to me, that means that your dial indicator may not have had enough preload set on it. It could also mean timing is grossly retarded but if it were that bad the engine probably wouldn't run.

Is that question I'm asking making sense? The setup and calibration of the dial indicator is a key step that is easy to overlook so may want to revisit that if you are not sure.

I still think the driveability (bucking and low power) you are mentioning could be improved with known correct timing. To be sure on cam timing you do need the locking tool. It is available on ebay very cheap for the VW application so worth getting one and getting it right. Easy to do with valve cover and rear cam gear removed. It does need to be correct. Eyeball is really not good enough -- again remember that, unlike say a TDI, this engine has no computer controls so it cannot compensate at all if things are not set up right.

The inconsistent RPM behavior does sound like air in the system but it could also be a light load misfire due to incorrect timing. Try timing first, once you are rock solid on being sure that's right, there would be other things to look at.

It will get there!
__________________
86 745 D24T/ZF 345k lifted 2.5"
83 764 D24T/M46 155k
Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -8. The time now is 12:19 AM.


Powered by vBulletin® Version 3.8.10
Copyright ©2000 - 2022, vBulletin Solutions, Inc.