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#1
12-30-2016, 12:32 PM
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740 2.4 TD GLE - D24+T Budget overhaul
Hi there.
I am in the process of doing a overhaul on my high-miler D24+T. It has been more and more annoyning to start in cold weather, due to lack of compression. But lately, another problem showed up. The engine coolant constantly turns black. I have done a coolant system flush, but it only lasts a few days, then the coolant is black again. So, now it is "engine-out-of-engine-bay-time"...  ...Black coolant   Also a bit leaky at the cylinderhead.  Pulled the engine out at a friends house, and took the engine with me home.  ...In the process of disassembling...   Finally got the head pulled off the block.  Good 'ol crackhead!  ...Cylinder wall on the 6th cylinder not so pretty. Budget overhaul = Just deglaze it, and then done   New vs. old pistonring. Guess which one is the new   Block-cleanup before a new coat of paint.    Piston-prep for new rings. Cleaning the grooves with a piece of old snapped pistonring.  Pistons ready for new rings, and new con-rod bearings...  When all the soot and dirt gets cleaned off, it reveals a thing that had happened in the engines youth. Notice valve-marks on the pistoncrowns. I think the engine have had a case of snapped-cambelt. I have driven this engine for a lot of KM's, so I decided the pistons are OK. Budget overhaul, remember More pictures will come, as the project proceeds... Happy newyear, ladies and gent's  / Dennis from Denmark. 
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#2
12-30-2016, 02:33 PM
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Good winter project!
What are you going to do about the crack in the head? Is that where the oil was mixing with the coolant? What kind of headgasket did it have, fiber or MLS? Did this engine run synthetic oil (wondering about the piston ring wear)? What was the oil consumption, before this recent catastrophic problem?
__________________
1985 744 gle d24t 1985 745 gle d24t
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#3
12-31-2016, 07:14 AM
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There is a solution to cracked cylinderhead. I have a spare, from my old engine where the cam-belt suddenly lost all its teeth
 The cam snapped in three pieces, but i assumed the head could be used again. It got twelve other used valves, and the lifters that were damaged got swapped with some good used ones. The valves are ofcourse re-lapped, and the valve-stem seals replaced.  Notice one the height of one of the last valves. Stuck in an unusual position = Bent valve!  ...A little bit stuck  A damaged lifter, notice the small cracks.  All the parts for the budget head-repair. Set of used valves, and a used cam.  Ready for fitting of the cam, and valve adjustment. The engine with the cracked head, had a two-notch fiber gasket. And when it comes to which one to choose for this project, I am in doubt. The "new" head is straight, and just cleaned by hand with one of these green "scotch brite pads". But do you think a MLS would be ok, when the block and head not have been machined? A thought would be that the fiber one is better for "imperfect" surfaces. This engine have always used a lot of oil. Started to run 5w/40 part synth on it, but then I had to refill quite often. Lately I had to refill more often, and tryed 10w/40 part synth, and it consumed 1 liter pr. 800-1000km. (0,26 US Gal to about 600 miles). Lately it also was a bit smokey out of the exhaust. A fine nice blue fog when engine was cold   There were also a lot of soot in the downpipe, due to the massive oil consumption. Anyway, I think thats why
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#4
12-31-2016, 08:07 AM
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Here is a video I did before the engine was taken apart. After a couple of minutes, the blue smoke is sort of noticeable. About 2-3 mins into the video.
https://youtu.be/Cq5dMGSIZ2A Another video. At operating temperature. Blue smoke not noticeable. Only the black, when it gets som revs. https://youtu.be/7-7FhNxVHfc /Dennis from Denmark
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#5
01-16-2017, 11:07 AM
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I made at little more progress the last few days.
 Cylinderhead ready for valve-adjustment..  One of the original tools. This is the "Valve-lift" tool. Notice the Volvo partnumber.  The other tool. This one made for changing of the valve-shims.  New piston rings, to be installed.   ...Lets get em' in!  Voila!  Also cleaned/refreshed the threads for the cylinderhead bolts... More pictures about to come in a few days. Waiting for the next shipment of parts, for this cheapskate overhaul :-)
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#6
01-16-2017, 09:04 PM
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Nicely done!
__________________
1985 744 D24T M46 49mm t3 @20psi 280k
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#7
01-23-2017, 12:32 PM
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Another update... I've been busy the last few days, so I only managed to get the cylinderhead torqued down. But next weekend, I have planned to put the rest of the engine together.
  Ordinary headgasket used in the rebuild. I do not want to go with the MLS, because neither the head or block have been machined.   To be continued... Next weekend
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#9
01-28-2017, 02:47 PM
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So... Now im almost done with the rebuild. Next step is to put the engine back in the 740
 One of the downpipe-studs snapped during disassembly. So I had to drill it out and make some fresh threads.   Injectors torqued in place. 297's.  Glowplug-testing before installing  "Wahler" Our preferred brand in thermostates, for these engines.  Running a stock turbo @ stock boostpressure.  Pump timing @ 0,97mm...  Decided to go crazy with the rattle-can..  Almost done..   More pictures are on their way.. 
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#10
01-30-2017, 11:37 AM
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Looks great. Some of those pistons got whacked hard by the valves, did the rods all look good? Checking piston out-of-deck height could have been useful to look at, but as you said, if it ran fine before, it will probably continue to be OK.
I agree with the choice of the fiber gasket, seems like they are more forgiving of a quick-n-dirty surface prep process and/or a little head warp beyond spec. Remember they need the retorque after 1000 miles that the MLS gaskets don't need, though. The color is a good one - should look nice when back under the hood of the car!
__________________
86 745 D24T/ZF 345k lifted 2.5" 83 764 D24T/M46 155k
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