Smoke. Clouds and clouds of smoke. 1984 300sd - Page 2 - PeachParts Mercedes-Benz Forum

rscurtis · #16 05-10-2012, 05:40 PM

It seems to have a miss at idle. That could be related to your smoke also.

angst · #17 05-11-2012, 12:32 PM

So, I am still at a loss for what to mess with next.
I have been meandering around pump timing threads and am considering fiddling with that. I do not have one of those drip tube things though.
The timing chain sounds like a possibility. Could a worn timing chain account for my symptoms?

Stretch · #18 05-11-2012, 12:50 PM

A drip tube can be made from a bit of cut off injector line (scrap yard visit in your future?).

The easiest thing to check first though would be the crankshaft timing - go through the more in depth 2mm method =>

PeachPartsWiki: Measuring Timing Chain Stretch

angst · #19 05-17-2012, 07:28 PM

I don't have one of those meters but I followed the tutorial Army posted and used the second method described of aligning and reading.

I seem to be getting a different reading every time I rotate the top around. One time it will be plus 10 and another time it will be minus 10.
I am not sure how sensitive the alignment of the mark should be.
Im not confident I have yet to get a reading dead center of the hash mark. It keeps wanting to hug either side of the mark.

From the attached pic does it look like I am centered on the mark enough to have an accurate reading?
The other pic attached is of the numbers taken at the same time as the alignment in the other pic.

And how do you read it exactly. Are you supposed to be looking from a particular angle? What is the reading in my pic? +7? -7?

Stretch · #20 05-18-2012, 01:16 PM

This sort of trouble is quite common for some reason or other when using that second method. I'm not sure why it is so unreliable I have my theories but I can't be sure so I'm not going to bring that to the table just yet...

I reckon you need to beg / borrow / steal a DTI (dial test indicator) and do the whole job if you want to do this. I will add that these gauges don't cost so so so much - and you will find that they are useful for other things (such as wheel bearing clearance measurements)

angst · #21 05-18-2012, 01:40 PM

Thanks Army.
I had just come to the same place in my mind that testing with a gauge was the next sensible thing to do. A stretched chain seems to really make sense with my symptoms and miles on the car (about 265k). I am pinning my hopes on that.

The gauges are in stock at my local HarborFreight store
I will pick one up in a few hours.

I have been reading up on this some more and am a little perplexed about the woodruf key. Anyone have a handy bookmark showing where it is located and how to use it?

If I knew where to look I could take a peek at any existing one that may be in there just for science to see if the chain has already been fiddled with before.

Stretch · #22 05-19-2012, 05:34 AM

Here you go

PeachPartsWiki: Camshaft Woodruff (offset) Key install

angst · #23 05-19-2012, 01:21 PM

Got stuck on some simple things since I have no idea what I am doing.

Quote:

3-Just remove valve lash.

What the heck? pic in the tutorial seems to show loosening the cap. Is the "lash" the cap part? Do I remove the cap completely? Throughout the tutorial it doesn't look like anything was removed.

Questions

1. Do I crank the lower nut down and then unthread the top nut till it comes off? For my test I just loosened the two valve adjusting nuts apart slightly. What should I be doing with them?

2. How do you read the gauge? I don't understand the scale. I started with my gauge at 0 and rotated the engine until the gauge rotated backward (counter clockwise) just shy of 1/4 of a full rotation to arrive at the position in the pic. The lobe of the cam is just shy of pointing straight down just like in the tutorial

3. How do you actually read the timing? Are you supposed to read to the left or to the right of the pin in the middle? Tutorial shows taking a reading to the left side of that pin. If mine is to the right does this mean I am 20 degrees off?

Stretch · #24 05-19-2012, 02:22 PM

Quote:

Originally Posted by angst

doing the dial test with the laptop out in the driveway now.
Got stuck on this simple step though

What the heck? pic seems to show loosening the cap. Is the "lash" the cap part? Do I remove the cap completely? In the pic later on showing putting things together it also doesn't look like anything was removed.
Do I crank the lower nut down and then unthread the top nut till it comes off?

Normally you'd have a clearance between the valve follower / rocker and the cam lobe. In this case you need to adjust it so there is no clearance. Don't grind it real hard up there though! Be gentle but make sure that when you look between the follower and cam lobe you can see no sunlight / torch light (well you'll probably see some small cracks shining through; the surfaces should be perfectly flat but hey ho...)

The point of this exercise that that the cam lobe pushes the valve open immediately.

Don't forget to adjust the valve when you are done - you need the clearance for when the engine is running.

angst · #25 05-19-2012, 02:48 PM

if I am understanding your right I should essentially adjust the valve, but instead of adjusting to the normal gap I should adjust it until the gap is right at "0" plus just a touch of additional pressure.
do I have that right?

Stretch · #26 05-19-2012, 02:55 PM

Quote:

Originally Posted by angst

if I am understanding your right I should essentially adjust the valve, but instead of adjusting to the normal gap I should adjust it until the gap is right at "0" plus just a touch of additional pressure.
do I have that right?

Leave out the additional pressure bit and you're good. Adjust to a clearance of zero mm or as near as damn it.

(Additional pressure is a bit vague - one man's additional pressure is another's flattened finger)

angst · #27 05-19-2012, 03:14 PM

sweet. I'm kind of getting somewhere.
With the valve "adjusted" to the point of not allowing a feeler in plus a little bit extra my observed measurement at the timing mark is pretty much the same.
Rotating the lobe from the starting position starts moving the gauge when the lobe is getting close to pointing down.
With the dial gague rotating counter clockwise not quite a 1/4 turn to "20" on the small red numbers the reading on my timing mark reads about "13" on the numbers to the right of the center.

So does that mean my timing is 2 off or 22 off?
22 off would mean a slam dunk that my timing chain is the issue right?

bigblockchev · #28 05-19-2012, 08:46 PM

I don't ever remember seeing a turbo with that much side play!!

Stretch · #29 05-20-2012, 05:11 AM

Quote:

Originally Posted by angst

sweet. I'm kind of getting somewhere.
With the valve "adjusted" to the point of not allowing a feeler in plus a little bit extra my observed measurement at the timing mark is pretty much the same.
Rotating the lobe from the starting position starts moving the gauge when the lobe is getting close to pointing down.
With the dial gague rotating counter clockwise not quite a 1/4 turn to "20" on the small red numbers the reading on my timing mark reads about "13" on the numbers to the right of the center.

So does that mean my timing is 2 off or 22 off?
22 off would mean a slam dunk that my timing chain is the issue right?

I want to make sure that I understand what's going on - so please excuse my pedantic questions.

1) You are "doing" this to the intake valve over cylinder #1 - right? That's the second valve from the front of the engine.

2) The deflection of the valve should be 2mm - that's 0.08 inches according to the DIY - is that what you've done?

3) If the answers to above two questions are good you end up reading 13 degrees AFTER TDC at the crank?

The intake valve needs to open AFTER TDC not before!

You now need to check which cam is fitted to your engine - there is a number stamped into the back of the camshaft => closest end to where the driver should be sitting.

If for example you have cam code 05 for a turbo motor (OM617a) then a new chain would be reading 9 degrees. If your measurement comes out at 13 degrees at the crank then you can calculate the elongation as follows =>

13 degrees - 9 degrees = 4 degrees elongation.

angst · #30 05-20-2012, 02:45 PM

MEGA EDIT.
nuke all that. I re-tested and used and read my dial gauge correctly this time (i think)
With my new dial reading skills and actually letting the dial spin around 3/4 of a rotation to 80/20 on the other side of the dial all my readings on the balancer are making sense now.
In the attached pic the red color was my old reading. My new reading is what I have annotated with purple.

With the dial gauge method the balancer reads 7
I also managed a flawless line-up when revisiting the aligning timing mark method which reads about minus 2. The reader arrow is aligned with the left edge of the pin.
(I realize now that the pin is not 0 but rather just to the right of it)

If I understand it right. with the gauge method it should read from 9 to 11 to be in tolerace and I have 7.
With the aligning marks method I should be getting +2 and my actual reading is -2.

I am now pretty bummed. I thought I had this figured out as a chain or key would put me back in business

If my timing is pretty close then it is going to be something else all together that is causing the smoke then right?
damn

Army I appreciate you help and want to be sure I addressed all the things you brought up

Quote:

1) You are "doing" this to the intake valve over cylinder #1 - right? That's the second valve from the front of the engine.

yes

Quote:

2) The deflection of the valve should be 2mm - that's 0.08 inches according to the DIY - is that what you've done?

Nope. Looks like I did the dial gauge wrong first time. With my new dial set up and reading skills I am getting a value of about 7 for the timing mark.

Quote:

3) If the answers to above two questions are good you end up reading 13 degrees AFTER TDC at the crank?

About 7 is the reading now with better dual use skills.

Quote:

You now need to check which cam is fitted to your engine - there is a number stamped into the back of the camshaft => closest end to where the driver should be sitting.

R617 051 12 13 is the number on the back of the tower part that holds the cam. That is the only number I could find back there poking around with a mirror.

Quote:

If for example you have cam code 05 for a turbo motor (OM617a) then a new chain would be reading 9 degrees. If your measurement comes out at 13 degrees at the crank then you can calculate the elongation as follows =>

13 degrees - 9 degrees = 4 degrees elongation.

Humm, so I am getting a bit shy of what even a new chain should read and numbers will go up as a chain wears. Does that mean my readings are still whack?