300D Timing Check - PeachParts Mercedes-Benz Forum

DSlater · #1 05-30-2009, 06:57 PM

When I line up the marks under the valve cover, the section of balancer that has the reading marks is still about a half rotation of the crankshaft away and the number one valve lobe is pointing to 3 o'clock.

From what I've been able to gather, being one tooth 'off' is equal to 18 degrees, which would seem like the ballpark my 'reading' is in. Exactly how is that possible? I've read what I can find about this issue and saw someone mention loosening the tensioner and using a 'wave' motion on the chain to bring it around a link. That makes some sense, but not really. It would seem that if you left a links worth of slack somewhere when putting the chain on, the chain wouldn't link up at all, and if a tooth was 'skipped', it would be too long by one link at the join point. Or do the chains not come with the correct number of links? Very, very confusing and frustrating.

I do not have a dial gauge or I would have tried that by now. And fwiw, the teeth on the cam gear look nice - square and sharp.

Diesel911 · #2 05-30-2009, 10:45 PM

You will have to re-check it and make sure you are on the compression stroke and that you rotate the Engine Clockwise viewed from the Radiator looking at the Engine. When it was a new assembled Engine it lined up on Zero indicating TDC (Top Dead Center). If for some reason you went passed the Timing marks you must continue to rotate the Engine Clockwise back to the mark. As, turning it backwards risk the Chain jumping teeth on the Timing Gears.
you need to get your Eye up really close to the Timing Marks on the Camshaft Gear and Chamshaft Bearing Tower; if you are looking at any sort of an angle it throws the reading off.

As the Timing Chain Stretches and the Timing Gears wear the Camshaft Timing becomes late and the Damper goes past Zero/Top Dead Center.

Also keep in mind you are checing the Camshaft Timing not the Fuel Injection Pump Timing.

Also you did not say why you were doing the check. If this happend after a Timing Chain Replacement or if you have had the Timing Gear off of the Camshaft it may indicate the Timing Chain slipped teeth or a tooth.
Here is a pic where on the left is a mark not alined on the right side of the pic is one alined. That little bit of differance made alot of differance down on the Crankshaft Damper.

Diesel911 · #3 05-30-2009, 10:56 PM

This is mine at 198,000 miles
The Damper marks (on the right side of the split picture) are hard to see but the pointer shows that my timing is late somewhere between zero and 5 Degrees. I figure my Camshaft Timing is about 2 degrees late.

DSlater · #4 05-30-2009, 11:25 PM

Thanks for the reply. I was editing while you were sending I think! Mostly I'm checking it because I never have. Also, my current mission is to eliminate the (fairly bad imo) nailing she has right now. In reading about nailing I came across a thread where things to check to make SURE it's just injector noise were mentioned and timing was among them. I just ordered the injector socket from Samstag today, so I can't swap them around yet.

Anyway, heres a few pics of what things are looking like for me:

JonL · #5 05-31-2009, 01:39 AM

Is it normal for the lobe to be at 3:00 when the marks are aligned that way? I don't have that engine, so I'm going from very hazy memories, but it seems to me that the lobe should be closer to vertical (but not quite vertical). Either 11:00 or 1:00. Perhaps it is the wrong washer that's in there?

DSlater · #6 05-31-2009, 01:51 AM

One more pic. The alignment of the pins is (seemingly) obviously suspect to me, but I have no frame of reference for judging how far out the left pin should be under 'normal' conditions.

DSlater · #7 05-31-2009, 01:59 AM

From what I can see of the lobe in the first pic of Diesel911's second post, it's also at 3 o'clock when the marks are aligned. Makes me feel a little better...

JonL · #8 05-31-2009, 10:50 AM

Quote:

Originally Posted by DSlater

From what I can see of the lobe in the first pic of Diesel911's second post, it's also at 3 o'clock when the marks are aligned. Makes me feel a little better...

Yes, it does look that way, but there's so little of the lobe showing it's kinda hard to tell for sure. I'd like to hear what he says, or perhaps he's got another picture to post.

Brian Carlton · #9 05-31-2009, 11:45 AM

Quote:

Originally Posted by DSlater

When I line up the marks under the valve cover, the section of balancer that has the reading marks is still about a half rotation of the crankshaft away and the number one valve lobe is pointing to 3 o'clock.

From what I've been able to gather, being one tooth 'off' is equal to 18 degrees, which would seem like the ballpark my 'reading' is in.

Let's get the facts straight, first. No work can be done to this engine until we are positive of where it currently is.

If the camshaft is aligned with the tower mark.........and from the photo, you've done this correctly, the crankshaft should be close to zero degrees. The fact that it is not is a problem.

The question is whether the crankshaft is "about a half rotation" which would equal 180 degrees........or is it actually 36 degrees.......which would be one tooth on the camshaft?

The engine cannot run if the error is more than one camshaft tooth........because the valves will hit the pistons. So, this discrepancy in the data must be resolved before we go further.

Diesel911 · #10 05-31-2009, 12:03 PM

Quote:

Originally Posted by JonL

Yes, it does look that way, but there's so little of the lobe showing it's kinda hard to tell for sure. I'd like to hear what he says, or perhaps he's got another picture to post.

Sorry, that is the only picture I have left.
I know it seems like extra trouble but what I do to be sure I am on the compression stroke is remove a Glow Plug and put my finger over the Glow Plug Hole while I turn. That way I feel tha air pushing against my finger I know it is the compression strioke.
That way I do not worry what position Camshaft Lobes are in.
Also with the Glow Plug remove it is slightly easier to line up the timing mark as you are not turning against the compression in the #1 Cylinder.

By the way, nice photograpy.

jt20 · #11 05-31-2009, 12:09 PM

the centerline of the first camshaft lobe is in line with the washer mark.

DSlater · #12 05-31-2009, 12:22 PM

Here's a pic of the balancer from under the car. The timing marks are still aligned. You can see that the section that has the pin sticking up is at about 190 degrees (the pin is anyway). Will try to get more shots if it will help, sorry for the blur.

Brian Carlton · #13 05-31-2009, 12:34 PM

Quote:

Originally Posted by DSlater

Here's a pic of the balancer from under the car. The timing marks are still aligned. You can see that the section that has the pin sticking up is at about 190 degrees. Will try to get more shots if it will help, sorry for the blur.

This becomes a more complicated issue.........it's not simply a result of a one tooth error on the camshaft. Some PO has done something that is totally in error.

However, the end result might still be acceptable.

What's the 0-60 time for this vehicle?

DSlater · #14 05-31-2009, 01:04 PM

I haven't put a watch to it, but seat of the pants I'd say it's definitely under 15 secs, for sure if I'm using S instead of D. She pulls about 2900rpm at 65mph in 4th. At a Florida hot idle after running 60mph+ for ~20mins, the oil pressure sits at 1.8. It's actually pretty quick now that I've performed about five years worth of maintenance on it in the last six months. Primary helps though were cleaning switchover lines, valve adjust, new filters all around, new vacuum X and Y connectors by the IP, and running some DP through it. In addition to checking the timing I opened it up this time to also check that the #1 cylinder valves were holding there setting after a week of running hard, and they are. I adjusted them several months ago but decided to check-up on them a couple weeks ago. The #1 cylinder intake was at .055 and the exhaust was closed so bad I think a .127 barely fit. Must have not locked the nuts tight enough on that one (or...?). Only one other valve needed a minor tweak.

She goes like hell, just has a steady thwack-thwack-thwack when at hot idle. Any rpm makes it go away, or so it seems so far. Just tuned in to really listening closely in the last few days and she's been apart for 36 hours now. Shakes a bit more than I think it should at hot idle too fwiw. Did motor and trans mounts but not engine shocks, helped some. Haven't messed with the rack dampener yet. She _really_ likes the DieselKleen, runs noticeably smoother and stronger with healthy dose of it. From the look of the injectors they've never been touched, which is what led me to investigating the sound as nailing, if that's what it actually is.

DSlater · #15 05-31-2009, 01:26 PM

And one other thing I had put out of my mind, but is worth mentioning. The trunk smells of vegetable oil. Not kidding. I have no other real evidence that it was running it save for these bolts in the engine compartment that look suspicious. No idea at what point in it's life it was, but the original owner had the car for it's first 15 years. After that the records start trickling off and basically end about 5 years ago with only oil changes in evidence after that. Last owner only had it about a year. Some bit of whatever was attached is still behind the left bolt: