If you are doing a major tune up what is the best place to start and the right order. IE check chain stretch repair if needed then adjust valves then time IP then adjust alda or adjust waste gate. Do you under stand my question I want to do a complete tune up what is the correct order of events
It is a 1979 300sd
Thanks Dave S San Jose Ca.

No expert, but I don't think it would hurt to do the valves first, the timing doesn't affect their amount of opening/closing and if you do the dial indicator method off the #1 valve it should be set right, but the rest sound like a good order to go after it.

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'84 300SD veg-oil bliss
'83 300SD veg-oil beater

The most important is the timing chain before the injector pump. If the chain is loose it will affect the injector timing. I would then do the valves, waste gate and then the alda. The alda is last because it gets its signal from the amount of boost.
Just my $0.02 worth.

If this is a new car to you, then in my opinion the best place to start is to plan on doing the valve adjustment - and while in there assess the timing chain.

If the timing chain is OK then you're set - if not you can get one ordered and continue on with the valve adjustment. If the timing chain is really elongated then you know not to drive the car, etc. etc.

I would leave the injection pump timing alone until you're pretty far along on other maintenance tasks.

And before alda & wastegate checks, I'd check the "banjo" bolt at the back of the intake manifold (near the firewall) and make sure that little pressure line going to the alda is clear.

Are you having performance issues or just working through a new car?

Oh, and if you find the valves are tight (as in no clearance - which is routine for a non-maintained car) then adjust them, run for awhile (maybe a few thousand miles) and then go back and set them again. They will need to seat themselves properly into the cylinder head after having been loose.

Ken300D

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1982 300D at 351K miles
1984 300SD at 217K miles
1987 300D at 370K miles

Don't stop with just the banjo bolt on the back of the intake. When I picked up my 300SD it was accelerating weakly. Read the threads here and asked a few questions. Checked that banjo bolt and it was plugged with gunk. Checked the line from it and it was plugged. Checked the crossover valve mounted on the firewall and it was also plugged solid. Once all those were clear it ran a lot stronger.
These old diesels sometimes do not get the care they deserve.

The motor is out of the car it was someone’s project that they never got to run. He took the head in had a valve job done never could get it to start and gave up on it. So far it has 1 degree at most of timing chain stretch. Valves are all over the place too loose too tight. I think the harmonic balancer is on 180 degrees out. I think this because something he told me I guess there must be some way to tell by the valves if #1 piston is at TDC. But only way I know is to put it so it should be at TDC put 5cc of oil in injector hole if it over fills then it really is TDC if it will take a pint of oil well then the harmonic balancer is on upside down. Does this sound like a sound way to check it?

You should be able to tell by lining up the valve timing marks on the cam shaft and checking where the harmonic balancer mark is. If the balancer is not showing TDC, then its on wrong. You ensure yourself that you don't get it on upside down by setting the valve timing mark first and then installing the balancer with the zero mark up.

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1976 240D
1987 560SL
2007 E320 Bluetec
1998 C280 (now son’s car)
1982 240D Manual - Sold

I got a manual that explains how to do that so I will do so. Unfortunately my 1985 300d euro needs a transmission I am going to try to rebuild it myself I think? I just ordered some manuals and am going to take a look inside before I order the parts so my motor is going to be put on hold for a few weeks.
Dave S

"But only way I know is to put it so it should be at TDC put 5cc of oil in injector hole if it over fills then it really is TDC "

You need to get this concept fully before you mess with your engine any more....

A four stroke engine takes two revolutions of the crank to make a full cycle...

THUS any piston is at the top TWICE during that cycle... what you are looking for is BOTH being at TDC AND being on the compression stroke....

Both valves will be closed on that upward travel during that stroke... and if turning by hand having either the glowplugs or the injectors out will lower the work involved.

Both cam lobes will be pointing away from the rockers and valves. This is assuming that your engine is timed correctly.

Is there no way to reach the top of the piston through the injector hole?

Is there no way to reach the top of the piston through the injector hole?

The prechamber effectively blocks anthing you might try.

You need to get this concept fully before you mess with your engine any more....

A four stroke engine takes two revolutions of the crank to make a full cycle...
Doesn’t that mean that the cam gear mark can line up and the harmonic balancer can show TDC when the piston is actually at the bottom. While the cam lobes show the valves to be closed, isn’t it possible to have the cam mark line up yet the harmonic balancer to be on upside down. The suspicion is he put the balancer on upside down then set the start of delivery on the IP and now the car wont start. Evan though it just had a valve job and compression is good. How can I verify the harmonic balancer is not on upside down or out of phase?
Thanks Dave S San Jose CA.

If compression is good then you can assume the valves/cam/crank are aligned ok ( someone yell loudly if there is any possibility this is wrong ).
Since this is pretty important.... perhaps you should consider pulling the number one precombustion chamber out ( pull glowplug first )... this will give you visual confirmation of the piston being at TDC and if both the valves are closed ( not being affected by the cam on the upstroke to that TD position ) then you can look at the crank and see if things are where they should be.
I was under the impression that it would be very hard to mount the harmonic balancer in the wrong position.....but I don't know for sure... are those pins 180 degrees away from each other ?
If your compression is good then your cam marks should be in the correct place with regards to number one being on compression stroke... the cam turns at half the rate of the crank... so ( assuming good compression) it will indicate #1 compression at TDC ..... where the crank position without other indicators is in the same position twice in a cycle... and you need to find the particular time it is at TDC for your determination as to the
balancer correctness... or not...
In OTHER words you check the position of the piston with other things... then look at the harmonic balancer to see if it is right....

We are also using this list for a new to my son 1979 300sd. We adjusted the valves fortunately all but 3 were in speck. We think this is a good Sign that it was cared for. It is a 1978 motor we have checked chain stretch on three other motors in the past. We could not find a mark on the camshaft sprocket we took an hour off for lunch after adjusting valves looked again still no mark. We got a very bright light still no line on the camshaft sprocket to line up with the one on the cam tower. We had our neighbor look no mark. We can’t find the line on the cam shaft sprocket to line up with the line on the cam tower. We pulled valve cover off 1980 300sd motor found the marks immediately. We are quite happy to see that the chain tensioner looks brand new and hope that means the chains new too but no kidding we can’t find a straight line on the cam shaft sprocket to line up with the one on the tower.
Our second adjustment after valves is throttle linkage because it was so obviously bent up and not traveling its full distance. Did MBZ ever use any thing other than a line on the cam shaft sprocket for alignment prepossess? There are several numbers, symbols logos but no straight lines if I get to it tomorrow I am going to pull the cover just to check again it must be there right?
Dave S

leathermang regarding the 1980 300sd motor. I guess I will have to make a pre combustion chamber tool I assume you mean too pull the glow plug so you dont brake it correct me if I am wrong. It was a crummy gas mechanic to begin with that put this motor together he took the harmonic balancer off while he had the head off never marked the chain to cam shaft sprocket and rotated the crank shaft to look at cylinder walls then guessed at putting it back together before he was finally thrown off the premises by the owner of the car. Regarding the compression test if the engine had the compression stroke occurring 180 degrees out of turn would it not still read good on a compression tester it would not care that it was injecting fuel while the valves were open just that the valves were closed on at least one of the 10 or so revolutions the motor turns during a test. Evan if the valves were open on 9 out of 10 turns you would still get a good reading if they were closed on the tenth turn I know that is not possible I hope you understand what I am getting at because I value you’re input greatly and I am in a little over my head on this someone else worked on it and screwed it up first I guess I am pretty convinced he put the harmonic balancer on upside down I checked you can do it. Also putting the timing chain on so it skipped links witch I know he did while it was like this he set the start of fuel delivery or whatever he did thinking he was doing that. He was hired to remove head have valve job reinstall head he dissembled the injectors in 1 pile of parts pulled the harmonic balancer to fix a non existent front seal leak and all kinds of good helpful stuff to do a friend a favor while the head was at the machine shop. Well that is how it ended up like this I have what should be a real good motor but the timing is all screwed up if I could only put a orange stick in the spark plug hole I would be fine but I do appreciate your input a great deal.