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Great news.
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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.
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86 745 D24T/ZF 345k lifted 2.5" 83 764 D24T/M46 155k |
#2
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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. |
#3
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Couple questions for you: Quote:
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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.
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1985 744 gle d24t 1985 745 gle d24t |
#4
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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. |
#5
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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:
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!
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86 745 D24T/ZF 345k lifted 2.5" 83 764 D24T/M46 155k |
#6
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I looked at a tutorial where I am pretty sure the guy said counter clockwise on the crank until the number on the dial stops rising and then back and see if it shows the same amount. Your way of doing it is way different so I will definitely check what the reading is with that. Today I noticed the car has started to run better and the smoke was just a thin haze when hot now so something is going on and it's being improved over time. |
#7
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I have driven a few D24 N/A 240s. Lots and lots of rowing the shifter for relatively meager benefits.
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1985 744 gle d24t 1985 745 gle d24t |
#8
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It turns out I accidentally put the wrong fuel in the car.
I looked at my purchases and saw that I had accidentally put biodiesel in the car. I guess the fuel nozzles looked very similar This could maybe be the cause for the bad running aswell? |
#9
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Not really, i think. Even regularly using Biodiesel would be alright except if you accidentally used the cheapo european *heating oil* by mistake. That was usually very low quality and highly acidic. IP seals hated it. Are you in Europe?
What did they call "biodiesel" btw? what percentage was it? b5,b20 or much higher such as b99? If clean and well filtered, they all are fine fuel into these cars. But not the heating oil ..idk if it was heating oil what you used. Last edited by RedArrow; 05-21-2022 at 09:16 PM. |
#10
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*High Quality* BD should run extremely similar to PetroD. Some notice it quiets the engine a tiny amount. Performance differences should be well within 10%. BD exhaust smells A LOT better.
BD *may* have a slightly higher gel point than winter grade PD but I think those low wintertime temperatures have passed in your area by this time of year. Not likely the cause of your problems, unless the BD was low quality or waterlogged. Warning: 100% BD can prematurely degrade non-BD compatible fuel system rubber (fuel hoses, older IP seals), causing them to soften and weep. OTOH, BD inherently has higher lubrication qualities than current ULSD, potentially increasing IP and injector lifespans (assuming IP seals are BD resistant). Previously you stated you thought eyeballing the camshaft timing was close enough and wouldn't cause performance problems. ("The cam timing could be a little bit wrong but I don't think that could effect the engine too much.") I don't have direct experience with this so will not overtly dispute that but--- Why would the factory make a special tool and additionally specify loading the adjustment 0.2mm to one side if eyeballing was close enough? Why should they complicate the process? Also: "Adjusted the valves to pretty much exactly to what the book says..." What is "pretty much exactly to what the book says?" Either followed the method and specs or not? If not, what did you do different? Did you measure clearance with the head fully torqued to the block or before? Hot or cold? Not meaning to run you around but there must be something amiss. We agree that it should be running better, not worse, after a new head, light rework, new headgasket, timing, etc., no? Let's verify and clarify where you are at now. Apparently the performance and driveability are continuing to incrementally improve? Acceptable smoke? Only remaining issue is low RPM stumble? Please clarify if I misread.
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1985 744 gle d24t 1985 745 gle d24t |
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