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1984 MERCEDES-BENZ 300 TURBO DIESEL, 1978 CHEVROLET K20 CUSTOM DELUXE
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Discussion Starter #1
so i checked the timing chain today but i am not sure what i found. when i turn the cam gear and line it up with the mark on the tower i am able to turn the crankshaft between 0-5 degrees before the cam starts to move. i am confused because i can set the timing mark at zero and the cam gear notch and cam tower line match perfectly but they also match perfectly when the timing mark is on 5 degrees.
 

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1984 300D
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What Engine is this and what Year and Model? You also did not say if it was 5 degrees before or after Top Dead Center (OT on the Crank Damper).
Don't forget to give the how many Miles are on the Engine.

Also this sort of check is only done in the direction of normal rotation of the Engine.
You line up the Camshaft Gear and Bearing Tower Marks exactly and then look down at the Pointer down by the Crank Damper to see the Degrees.

If when you do that you are showing 5 dgrees that is an extremely rough estimite of your Timing Chain/Gear Wear. Often referred to as Timing Chain stretch.
If you really did a good job of lining up the Camshaft Timing Marks and are getting 5 dgrees after top dead center you might consider doing the 2mm Method wich is the definiative method to determing the Timing Chain Stretch.

If after doing the 2mm Method you still have 5 Degrees of Timing Chain Stretch you have 2 options. One is to install an Offset Woodruff Key on the Camshaft Shaft or to replace the Timing Chain.

If all of the below picture shows up on the left side of the picture is the Camshaft Timing Marks lined up and on the Right side is the Crank Damper and the Pointer is showing about 2-2.5 degrees after top dead Center (That means my Camshaft Timing is late by 2-2.5 Degrees).
I did this check at about 200,000 miles.
 

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1984 MERCEDES-BENZ 300 TURBO DIESEL, 1978 CHEVROLET K20 CUSTOM DELUXE
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365 Posts
Discussion Starter #3
hello, i have a 1984 300d with the 3.0 5 cylinder turbo diesel. i will have to recheck my marks tomorrow because i forgot what they read exactly. also could you explain the 2mm method and is it easy to do. thank you very much for your response and pictures.
 

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1981 W123 300D non turbo, 1992 190E 1.8 <=> 2.0
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hello, i have a 1984 300d with the 3.0 5 cylinder turbo diesel. i will have to recheck my marks tomorrow because i forgot what they read exactly. also could you explain the 2mm method and is it easy to do. thank you very much for your response and pictures.
Easy to do?

Well after the first time! And after you realise that what you read at the crank isn't the end of it. Read on!

PeachPartsWiki: Measuring Timing Chain Stretch
 

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1984 MERCEDES-BENZ 300 TURBO DIESEL, 1978 CHEVROLET K20 CUSTOM DELUXE
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Discussion Starter #5
hello. i have decided to change my timing chain. this might sound like a dumb question but i would like to know if there is a cover on the front of the motor that can be taken off to replace all the timing chain guide rails. also should i replace the gears that the timing chain wraps around. if i should replace the gears i am only able to find the cam gear and not the crank gear. is it worth it to replace just the cam gear and not the crank gear or should just leave the gears alone. also i want to replace the oil pump chain and guide rail. its cheap and i think it is good insurance. how easy is it to replace the oil chain. has anyone ever done it before. thank you for your help everyone so far. btw the car has 262000 mi on it.
 

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1981 W123 300D non turbo, 1992 190E 1.8 <=> 2.0
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There is no cover that comes off the front of the engine. You need to do a fair amount of part removal and fiddling about to reach it all.

The guides can be removed after the chain is out of the way by using metric nuts and bolts as pullers to withdraw the locating pins. Use nuts and washers that are larger than the thread on the bolt that you screw into the end of the locating pins to act as reaction blocks.

Before you start this job I think you need to get hold of a copy of the factory service manual (FSM). This can in principle be found at www.startekinfo.com You can also find information via the on line tech links thread sticky at the top of this forum.

To the best of my knowledge all of the cogs are widely available - I would check for wear on your existing cogs before replacing them however. Original parts on these cars - even worn ones - sometimes last longer than new patern part replacements. I wouldn't be in a rush to replace old parts with new just for the sake of it. You will not necessarily be buying yourself future reliability...
 

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1984 MERCEDES-BENZ 300 TURBO DIESEL, 1978 CHEVROLET K20 CUSTOM DELUXE
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Discussion Starter #7
If there is no front cover how do they get the gears in there. also do you think it is wise to change the oil chain. how do the guide rails come out. also will the head need to come off. thank you. ps does anyone have a chain crimping tool i can borrow.
 

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1981 W123 300D non turbo, 1992 190E 1.8 <=> 2.0
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Follow the links to the FSM - all will become clear!

The head does not need to be removed - just the lower oil pan and the valve cover up top and the vacuum pump...
 

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1984 MERCEDES-BENZ 300 TURBO DIESEL, 1978 CHEVROLET K20 CUSTOM DELUXE
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Discussion Starter #9
timing chain guide rails help

hello. i am going to change the timing chain on my 1984 300d 262000mi. anyway i wanted to know how to check my guide rails for wear and what to look for. also if i do decide to change my guide rails what about the bearing bolts. i have no problem getting the bearing bolt out but what if they need to be replaced. how much are they and where do i get them. also are there different sizes of the bearing bolt thank you. how many miles can you get out of your guide rails. thank you.
 

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"(That means my Camshaft Timing is late by 1-2.5 Degrees)"
Did you adjust injection pump timing based on late camshaft timing?
 

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"(That means my Camshaft Timing is late by 1-2.5 Degrees)"
Did you adjust injection pump timing based on late camshaft timing?
That should have been 2-2.5 Degrees of late Camshaft timing.

Yes, I re-timed it with the Drip Method and also later I removed the Fuel Injection Pump to change the Block to Fuel Injection Pump Gasket.

When I did the re-install of the Fuel Injecting Pump I use a Timing Locking Pin instead of doing the Drip Timing. I was able to do that because My Fuel Injection Pump has the port on it that fits the Tool.

At some point I need to Drip Time again as I am not sure the Timing Locking Pin gives the optimal Timing. But, the using the Pin is entirely Functional

I also have the Metric Dial Indicator and Base to do the 2mm Method but like doing the Drip Timing I cannot get up the motivation to do them.

I have new Flex Discs for 3 weeks and have not got around to changing them.

I guess I keep waiting for the Mercedes Good Fairy to do those jobs for Me:)
 

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Interesting.
My opinion is that injection pump timing is an imprecise manual procedure.
It looks like MB had a more precise electrical procedure and it was not deployed or was not used by dealers. Most likely because they didn't bother to check pump timing.
I would be inclined to advance the timing 2 to 4 mm and call it done. If it has a negative effect then take out some and drive test again.

I did the Flex and Drive Line Center Support and Bearing a week ago. MSource for the Support, bearing and instructions. Damn near didn't get it done even though I used a wheels hanging auto lift.
Issues and fixes:
*Use a bungee cord to support the exhaust near rear bumper. Drop the exhaust to access the Support and 46mm pinch nut.
*The 46 mm is tight access. 15 inch adjustable might work better.
*Tranny spport bracket and mount must be removed.
*Use a medium size pry bar to deflange.
*The shaft balance was marked each section. Use tape markers to be sure.
*A 2 leg puller extracted the Support but could not free the bearing. Treat the bearing with PB. It took a hefty 3 leg puller. The assy went on easy after emery cloth and oil.
"V" Support apex to differential and dust cover next to joint opens towards the Support. Note on disassembly.
*I used Lemforder disks. Nice quality. Has allen hex bolts which caused some interference problems tranny disk due to length of allen tip. All bolts head facing the shaft. Flex Disk embossed characters facing shaft both ends.
*I could not get enough forward shaft movement to flange the new rear disk differential side. Lacked 1/8 inch to slide the shaft with the shaft flanged disk up and on the differential shaft. This after flanging the front disk both sides to ensure full forward drive shaft position. Finally assisted by guy in the shop who had owned MB and had installed disks, bearing. He, big guy, pried and I max effort banged the shaft up and into position. Otherwise SOL.
 

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Interesting.
My opinion is that injection pump timing is an imprecise manual procedure.
It looks like MB had a more precise electrical procedure and it was not deployed or was not used by dealers. Most likely because they didn't bother to check pump timing.
I would be inclined to advance the timing 2 to 4 mm and call it done. If it has a negative effect then take out some and drive test again.

I did the Flex and Drive Line Center Support and Bearing a week ago. MSource for the Support, bearing and instructions. Damn near didn't get it done even though I used a wheels hanging auto lift.
Issues and fixes:
*Use a bungee cord to support the exhaust near rear bumper. Drop the exhaust to access the Support and 46mm pinch nut.
*The 46 mm is tight access. 15 inch adjustable might work better.
*Tranny spport bracket and mount must be removed.
*Use a medium size pry bar to deflange.
*The shaft balance was marked each section. Use tape markers to be sure.
*A 2 leg puller extracted the Support but could not free the bearing. Treat the bearing with PB. It took a hefty 3 leg puller. The assy went on easy after emery cloth and oil.
"V" Support apex to differential and dust cover next to joint opens towards the Support. Note on disassembly.
*I used Lemforder disks. Nice quality. Has allen hex bolts which caused some interference problems tranny disk due to length of allen tip. All bolts head facing the shaft. Flex Disk embossed characters facing shaft both ends.
*I could not get enough forward shaft movement to flange the new rear disk differential side. Lacked 1/8 inch to slide the shaft with the shaft flanged disk up and on the differential shaft. This after flanging the front disk both sides to ensure full forward drive shaft position. Finally assisted by guy in the shop who had owned MB and had installed disks, bearing. He, big guy, pried and I max effort banged the shaft up and into position. Otherwise SOL.
During 1975-1980 I worked in a Fuel Injection Shop.

After a Bosch inline Fuel Injection Pump was re-assembled during a rebuild each of the Elements (Plungers and Barrels) was Drip Timed (a.k.a. Flow timed).
We had a Gravity Feed setup to take care of the Fuel Pressure and you attached a Degree Wheel to the drive end of the Fuel Injection Pump.
At X mount of degrees (at Full Throttle) #1 Element had to drip X amount and then you did the same to the rest of the Elements each at their specified degrees.
If they were not correct there was an adjustment on the Tappet or you exchanged thickness of a Shim on the Tappets.
(I never saw an MW pump back then; the MW has those adjustment shims on top of the Fuel Injection Pump Housing and under the Element Flanges.)
So the whole Fuel Injection Pump was Drip Timed (where I worked they called it Phasing the Pump); just like you do when you time the Fuel Injection Pump on the Engine.

Other inline Fuel Injection Pumps besides Bosch ones were timed in a similar manner and it seems to be entirely adequate.

On Caterpillar Fuel Injection Pumps you did the same but you used a Dial Indicator or a Depth Micrometer.

On a 617.952 the Timing/Locking Pin, the A&B Light and the RIV Method all use a port on the side of the Governor Housing.
The Pickup that screws into the port references on a raised sort of blade portion of the Camshaft.
(The Timing/Locking Pin is cheap and easy to use, The A&B Light is easy to use but costs more, The RIV Method setup has a hefty cost to it and is slightly more complicated than the A$B Light.)
So when you use this method of timing you are Timing the Fuel Injection Pump Camshaft to the Engine at 15 Degrees ATDC (After Top Dead Center).

You decide which is more precise:
The 3 methods that use the Fuel Injection Pump Camshaft as a reference only times the Camshaft correctly and does not compensate for any of the wear on the Camshaft or the Tappet Rollers.
With the above method all of the Elements could actually be of time due to wear as this method does not check any of the Elements.

The Drip Method of timing compensates for the wear on the Camshaft and the Tappet Rollers but it only does that on the #1 cylinder.
(The Drip Method is cheap because you can make your own Drip Tube. But, people have trouble doing it. Once you know the technique it is not a problem.)
With the Drip Method the #1 Cylinder gets timed good but it is possible for the rest of the Cylinders go be off time; because you do not check the rest.

I also bought the Lemfoerder Flex Discs; made in Germany and if you shop around cost the same as the lesser Brands that claim to be OEM.

I know how to replace the Flex Discs I just have trouble with motivation; part of it is I am over 60 years old now.

Below is the last time I had the whole Drive Shaft off and about 3 Months ago I had the Differential End of the Flex Disc off as I had to remove the Differential and Axles to make room to do some Welding on the Rear Cross Member.
My U-joint Repair thread 2011
http://www.peachparts.com/shopforum/showthread.php?t=293976
My Benz World post with all of the U-joint sources.
http://www.benzworld.org/forums/w123-e-ce-d-cd-td/1581728-another-u-joint-driveshaft-thread.html#post4677977
 

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Interesting but I'll pass as the engine idles and runs well with no black smoke issues.
I did clean the injector pump with the MSource kit. Recycles cleaner through the system. Significant amount of carbon granules in the prefilter. I changed the primary filter and left the prefilter. Most of the granules have dissolved. The process did result in a noticeable engine response smoothness. Sweet running MB D.
 
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