Hi! My name is Matthew and I daily drive a 1982 300d, some of you may have seen my rebuild thread. The motor is completely gone through, thousands invested and,unfortunately, everything is not perfect. Ive been trying to diagnose my problems for about 6 months now and no luck. So I decided that it would be smart to get some outside opinions and help because many people are smarter than one. Let it be known I have done my hw, probably cumulative hours spent on this forum would add up to days, and I've tried all the simple obvious things. Anyway, I will list out the problems, symptoms, and what ive tried as follows, any help or pointers or even ideas would be incredibly helpful!!

1. The Vibration, the Smoking, the Blow By.
As I said earlier the engine is completely gone through. New cylinder sleeves bored to spec of the pistons. Pistons measured and weighed all in spec of each other. Head was completely redone, new exhaust valves, vacuum tested, valve stem seals, valves adjusted (and frequently checked!). Brand new injectors. All of the things that I would think could possibly contribute to this fairly brutal idle vibration, the constant WHITE smoke out the tail pipe, and some pretty substantial blow by. EXCEPT, the injection pump. Well, months later, I now have the injection pump rebuilt. New delivery valves, internals, and calibrated. I was expecting this to cure the majority, if not all of my problems. Granted, all of the problems(except blow by), were noticeably reduced, I still dont consider it a complete win. At this point im starting to believe that all of these problems are connected. Perhaps the machine shop botched the head, im getting blow by from leaky valves, which is also causing it to run rough and smoke..?...? I have no idea, my next test will be the compression. Hopefully that will tell us something interesting. Feel free to ask questions, and any thoughts are helpful! Really need to get this guy fixed as I cant have it consume my life, and bank account, forever..

2. Oil Cooler lines.
Yes, kind of off topic, but scary to say the least. I have brand new oil cooler lines, replaced during the rebuild about 6 months ago, and what do you know?! Leaking like a siv above the ac compressor.... I want a more reliable, more permanent fix, that wont leave me wondering if ill ever be stranded on the side of the road with a seized engine. #1 fix in my head is practicing brazing on the old lines, braze on some an fittings, and run short braided an flex line. #2 is tapping the oil cooler for an npt fitting? Then converting to an, then running an line straight from cooler to filter housing and getting metric to an fittings for the housing? Any thoughts on which would be better? Or possibly even better ideas?

I know you guys will be helpful, always are, so thank you in advanced! Hopefully we can solve these problems together.
Have a blessed day!

Did you spec the camshaft?

Timing is spot on?

If air was getting in the fuel, you would have rough idle, and white smoke...

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John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!

I agree check the static timing if you are getting white smoke = un burned fuel
Oil cooler - search for thread by Mach4 on -AN fittings and hose.

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The OM 642/722.9 powered family
Still going strong
2014 ML350 Bluetec (wife's DD)
2013 E350 Bluetec (my DD)

both my kids cars went to junkyard in 2023
2008 ML320 CDI (Older son’s DD) fatal transmission failure, water soaked/fried rear SAM, numerous other issues, just too far gone to save (165k miles)
2008 E320 Bluetec (Younger son's DD) injector failed open and diluted oil with diesel, spun main bearings (240k miles)

1998 E300DT sold to TimFreeh
1987 300TD sold to vstech

Make a trip to Harbor Freight for a compression tester AND a leak-down tester. The leak-down really gives more useful info than compression though both are helpful.

I'd listen especially to VStech - very sharp hombre. I'm guessing he's giving you the best place to start.

Dan

How many minutes has the engine run after the rebuild and how did you seat the new rings? How did you time the IP?

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85 300D turbo pristine w 157k when purchased 161K now
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

That was going to be my question. If it hasn't been run for very long, there is a good possibility that the rings have not seated yet. Just a stab in the dark.

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96 E300d

After doing all that work and you still have this?

Stop spending money until you know what is going wrong!

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1992 W201 190E 1.8 171,000 km - Daily driver
1981 W123 300D ~ 100,000 miles / 160,000 km - project car stripped to the bone
1965 Land Rover Series 2a Station Wagon CIS recovery therapy!
1961 Volvo PV544 Bare metal rat rod-ish thing

I'm here to chat about cars and to help others - I'm not here "to always be right" like an internet warrior



Don't leave that there - I'll take it to bits!

Egr valve not sealing or closing? Cam off one tooth? Really carefully drip timed?

If none of the above I would verify the engine harmonic balancers indicator is dead on by filing the number one cylinder with light oil when approaching the top of the stroke.

Seal a straw into the number one injector opening and advance the engine until the oil level in the straw peaks. This of course should show 0 degrees at the balancers pointer. Just a few considerations I might check. No certainty any of them are the issue.

At least these are the least complex things that occur to me other than air ingress or a very weak fuel supply at idle. Being a slow thinker if anything else bubbles to the surface in the next day or so I will mention it as well. You have to give working mechanics their due. Their instinctual strength is hard to replace. Unfortunatly I am not one.

Before doing a lot of things you have already done. In my case I would have employed the milli volt method in the archives to reduce the shotgun approach. What it would have shown or not shown is almost always signifigant if done with no short cuts. It can avoid the blind leading the blind syndrome when there is no indication of cause.

I agree and it is self serving for me. I really dislike spending money and effort where not needed. It could have gone to a much more useful need. Plus it consumes a lot of time.

It may have also been a learnt thing in my career. I was almost always forced to run down a problem with various tests to the actual component issue. Even when I at times had to manufacture a test protocol.

I still at my advanced age have problems come up that require a day or two to decide their most likely cause. Especially when I have designed the function they are to preform.

The blowby is the problem. Until that is solved, all the other "fixes" are just a waste of time and money.

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'83 300D, 126K miles.

I'd run a compression test first.

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

Blow-by has to do with engine internals (piston rings, cylinder walls). Do not spend a single dollar more until you figure out the compression numbers on each cylinder. Bad / uneven compression will make the engine shake and vibrate, especially at idle.

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[GONE] - 1995 Mercedes E300 Diesel - 130k miles - Smoke Silver (702) over Mushroom leather (265) - Bladder blasting, coast-to-coast work machine.

Well it may not or may be the problem. Every engine I have rebuilt has never had heavy blowby after putting it back together.

Perhaps luck in my case yet it seems strange to me to be noticeably present. I never rebuilt a 616 or 617 though as well. If I did from my past experience I would still not expect this.

Thank you guys so much for the quick responses! I will just go ahead and answer our questions in chronilogical order.

1.vstech: The camshaft was not spec'd, but looks very very healthy, no scoring or scratches or rounded lobes.
The timing is absolutely perfect, unless the marker is wrong. was very careful with that.
How would air get in the fuel?
-I was very suspicous of ip timing, but drove it for months dailyat exactly 24* BTDC(carefully drip timed). When the new pump went on, I timed it at 26*BTDC to try and reduce some cold start coughing. That solved that issue, and seems a tad more responsive.

-Compression Tester is going on order very very soon. Not a fan of Harbor Freight.

-The engine has run for months on a dailybasis, so I think its out of the break-in period... And the IP is drip timed.

-The money is being spent on things that would get replaced anyway. Every compenent before I started had 250k+ miles on it. It may seem crazy, but the goal of this project is to get the car back to its original glory to experience exactly what the person who drove it off the lot in 1982 felt.

-Like I said earlier, as far as I can see the engine reads perfectly timed, but that is a very good idea for checking if the markers are right. Do you mean just stick a straw in the prechamber and tape the base of it? How do you seal it in?



Once again, thank you guys. Already lots of useful info and things I need to try now.

Heres another question though. the other day when we were in checking the valves, we found large traces of oil in the air cleaner flex tube, and into the turbo. Now while i know this is coming from the top of the valvecover into the oil seperator, and while im posotive the oil seperator isn't doing its job, do you think that it is just the fact that the excessive blow by is shoving more oil up there than the seperator was ever meant to handle?

Thanks!
- Matthew.

https://www.flickr.com/photos/113280060@N03/with/13308911603/
Here are some photos documenting the rebuild process also, for your enjoyment.