Mercedes-Benz Forum banner

1 - 13 of 13 Posts

·
Registered
1979 Mercedes Benz 300TD 4spd Manual (Euro)
Joined
·
12 Posts
Discussion Starter #1
Hello!

I'm the new guy here. I'll be sure to pester and ask some stupid questions. I imported a '79 300TD 4spd manual from Germany and am completely addicted to working on it.

Some things I'm troubleshooting at the moment are:

Rough Starts - converted from series glow plugs to monarch parallel.

Lots of white smoke on start. No smoke once warm - plan to swap in new valve stem seals.

Some oil leaks - plan to replace a few different gaskets. I use the Liqui Moly 10w40 high mileage.

I did a compression test on the engine last week when it was stone cold. Results - #1: 340 #2 340 #3 300 #4 325 #5 325

Today I wanted to start with my valve stem seal replacement and, as a part of the job, I checked the cars internal timing since you need to get the car to top dead center anyway. When lining up the marks on the camshaft/cam tower, the counterbalance dial wasn't even close to the TDC mark. However, the camshaft lobes on piston #1 were in the positions suggesting TDC. My mind then went into a bit of a pretzel as I know you can be 180 degrees off, however, going with the opposite approach of getting the counterbalance to TDC, the marking on the camshaft was at a little less than 12 o'clock, not even close to the raised arrow on the cam tower.

Lastly, when lining up the marks on the camshaft/camtower, the dial on the counterbalance perfectly lines up with another random line carved into the counterbalance. Is it possible that someone along the way didn't do some timing work completely right and fudged a different TDC mark on the counterbalance?

Anyway, from a paranoid and anxious new w123 owner, I appreciate your help! I've read that driving these cars with bad internal timing is a good way to fry the engine.
 

·
Registered
1979 Mercedes Benz 300TD 4spd Manual (Euro)
Joined
·
12 Posts
Discussion Starter #2
Hello!

I'm the new guy here. I'll be sure to pester and ask some stupid questions. I imported a '79 300TD 4spd manual from Germany and am completely addicted to working on it.

Some things I'm troubleshooting at the moment are:

Rough Starts - converted from series glow plugs to monarch parallel.

Lots of white smoke on start. No smoke once warm - plan to swap in new valve stem seals.

Some oil leaks - plan to replace a few different gaskets. I use the Liqui Moly 10w40 high mileage.

I did a compression test on the engine last week when it was stone cold. Results - #1: 340 #2 340 #3 300 #4 325 #5 325

Today I wanted to start with my valve stem seal replacement and, as a part of the job, I checked the cars internal timing since you need to get the car to top dead center anyway. When lining up the marks on the camshaft/cam tower, the counterbalance dial wasn't even close to the TDC mark. However, the camshaft lobes on piston #1 were in the positions suggesting TDC. My mind then went into a bit of a pretzel as I know you can be 180 degrees off, however, going with the opposite approach of getting the counterbalance to TDC, the marking on the camshaft was at a little less than 12 o'clock, not even close to the raised arrow on the cam tower.

Lastly, when lining up the marks on the camshaft/camtower, the dial on the counterbalance perfectly lines up with another random line carved into the counterbalance. Is it possible that someone along the way didn't do some timing work completely right and fudged a different TDC mark on the counterbalance?

Anyway, from a paranoid and anxious new w123 owner, I appreciate your help! I've read that driving these cars with bad internal timing is a good way to fry the engine.
I should add that there does not seem to be any play at all when pulling upwards on the timing chain. It seems very tight.
 

·
Registered
W123 300CD, W123 300TD, W202 C250D Turbo
Joined
·
334 Posts
A manual wagon all the way from the fatherland !!! ... How did you prize that away from the oldtimer market there as I suspect they are highly valued. Enjoy working on it as all problems are solvable with patience and logic (and the closet to an onboard computer you will get is the tuner in your radio).

There are two sets of marks on the harmonic balancer. One for TDC and the other for timing the IP pump at 25° BTDC. Don't get the 2 confused like I did where I fitted the IP at TDC and wondered why I couldn't get it to start .... eventually I retraced my steps and found the error. I doubt any fudging would work as they are pretty picky about lining things up.
 

·
Registered
1979 Mercedes Benz 300TD 4spd Manual (Euro)
Joined
·
12 Posts
Discussion Starter #4
A manual wagon all the way from the fatherland !!! ... How did you prize that away from the oldtimer market there as I suspect they are highly valued. Enjoy working on it as all problems are solvable with patience and logic (and the closet to an onboard computer you will get is the tuner in your radio).

There are two sets of marks on the harmonic balancer. One for TDC and the other for timing the IP pump at 25° BTDC. Don't get the 2 confused like I did where I fitted the IP at TDC and wondered why I couldn't get it to start .... eventually I retraced my steps and found the error. I doubt any fudging would work as they are pretty picky about lining things up.
😀 yes, I was looking for a long time and finally found one that seemed suitable. My choices were to buy an auto turbo in the USA or a non turbo stick shift from Europe. I favored the latter and don’t really get too stressed about the backed up traffic behind me.

so there is only one set of numbers on my counterbalance.

I bring the markings on the camshaft/tower together, which brings the #1 valves into what I believe to be TDC. When looking down at the counterbalance markings, I’m nowhere near the TDC markings. However, there is this mysterious (to me anyway) line that is present maybe 2-3 degrees from the pointer. I’ve attached some pics.

thanks for your help!

2662422
2662423
2662424
 

·
Registered
1984 300D
Joined
·
5,196 Posts
Locate the intake and exhaust camshaft lobes for the cylinder you are going to work on. When the lobes form a "V" with the tips of the lobes pointing up you are near TDC on that cylinder.
 

·
Registered
'85 300TD Turbo
Joined
·
6 Posts
Also a new OM617 owner here and also getting familiar with the ways of the turbo diesel. I adjusted the valves this weekend and want to verify cam timing while I was at it. These are pictures of the cam lobes with #1 at TDC and the 2 timing marks. Everything look good to you guys and girls?
2662486
2662487
2662488


Thank you all!

Showtime, I hope you get it figured out. Looks like a PO might have bodged something.

Cheers
Alex
 

·
Registered
1979 Mercedes Benz 300TD 4spd Manual (Euro)
Joined
·
12 Posts
Discussion Starter #7
Also a new OM617 owner here and also getting familiar with the ways of the turbo diesel. I adjusted the valves this weekend and want to verify cam timing while I was at it. These are pictures of the cam lobes with #1 at TDC and the 2 timing marks. Everything look good to you guys and girls? View attachment 2662486 View attachment 2662487 View attachment 2662488

Thank you all!

Showtime, I hope you get it figured out. Looks like a PO might have bodged something.

Cheers
Alex
Alex, that looks mint to me. Well done!
 

·
Registered
W123 300CD, W123 300TD, W202 C250D Turbo
Joined
·
334 Posts
looks like 0.5° chain stretch to me but that could be parallax error in the photo and me just being a bit picky .... I would be happy with that result.
 

·
Registered
1982 300d four speed turbo & 1984 300d four speed N/A euro
Joined
·
389 Posts
looks like 0.5° chain stretch to me but that could be parallax error in the photo and me just being a bit picky .... I would be happy with that result.
Off-topic but what a good word. Parallax. My exact thoughts. If there was ever a time and place for that word, it would be here.
 

·
Registered
1979 Mercedes Benz 300TD 4spd Manual (Euro)
Joined
·
12 Posts
Discussion Starter #10
Also a new OM617 owner here and also getting familiar with the ways of the turbo diesel. I adjusted the valves this weekend and want to verify cam timing while I was at it. These are pictures of the cam lobes with #1 at TDC and the 2 timing marks. Everything look good to you guys and girls? View attachment 2662486 View attachment 2662487 View attachment 2662488

Thank you all!

Showtime, I hope you get it figured out. Looks like a PO might have bodged something.

Cheers
Alex
So, after speaking with a seasoned w123 enthusiast in my area, he mentioned that the counterbalance can be attached in six different positions and its likely that the person put the counterbalance on in the incorrect position and made a new mark for TDC. Furthering this thought, the counterbalance position on the pulley can affect timing and engine performance, however, if in the opposite position from the original TDC, the timing is perfectly fine. My personality is such that I really want to get that counterbalance back in the correct spot though! Thanks to everyone for your input here!
 

·
Registered
W123 300CD, W123 300TD, W202 C250D Turbo
Joined
·
334 Posts
I would want the counterbalance in the right place as well, to ensure complete harmony in the system. Thanks for letting us know as that adds to the knowledge bank
 

·
Registered
1982 300d four speed turbo & 1984 300d four speed N/A euro
Joined
·
389 Posts
So, after speaking with a seasoned w123 enthusiast in my area, he mentioned that the counterbalance can be attached in six different positions and its likely that the person put the counterbalance on in the incorrect position and made a new mark for TDC. Furthering this thought, the counterbalance position on the pulley can affect timing and engine performance, however, if in the opposite position from the original TDC, the timing is perfectly fine. My personality is such that I really want to get that counterbalance back in the correct spot though! Thanks to everyone for your input here!
For the record, the crankshaft pulley can be bolted on 6 different ways which is arbitrary since the balance is neutral. The harmonic balancer, however, can only be mounted two ways as there are two keys that fit into the keyways on crankshaft:



The person before you probably got it 180 degrees off. Basically, a 50/50 shot if you don't mark it.

Someone correct me if I'm wrong
 

·
Registered
1982 300d four speed turbo & 1984 300d four speed N/A euro
Joined
·
389 Posts
Also, you might as well replace the front crank seal while you're in there since you have to remove all of the front end anyways.
 
1 - 13 of 13 Posts
Top