Timing Chain SOS - please help!! - Page 4 - PeachParts Mercedes-Benz Forum

sixto · #1 02-22-2009, 03:50 PM

+22* is 22* ATDC or BTDC? Spec is 15* ATDC so 22* is not too far off. Might not be within the adjustment range of the IP. Might have to move the IP timer a spline or two to get it in range.

What do you mean cam timing is 180*? Cam timing when the IP lug is showing is irrelevant. Give the crank another spin to align the cam notch with the cam tower then read the crank pulley again.

Sixto
87 300D

Ace Taxi · #2 02-22-2009, 04:05 PM

To clarify:

By +22* I meant 22* ATDC, that is, the hash marks to the RIGHT of 0* as you look down on the crank pulley.

JonL · #3 02-22-2009, 04:12 PM

Looking down at the pulley, the marks reading left to right start at ATDC. In other words:

ATDC 30 20 10 0T 10 20 30 40 BTDC

I don't recall exactly the marks, and the "ATDC," and "BTDC" aren't actually marked.

Here's what you want it to look like when the pump is timed properly:

20 * 10 0T 10 20 30

0T is TDC. the * is where you want the pointer on the front cover. The number one cam lobes should be pointing more or less away from the valves, in other words, valves closed.

Ace Taxi · #4 02-22-2009, 04:28 PM

Then if I have the nomenclature correct, the crank pulley reads 22* BTDC with the tang visible.

30 20 10 0 10 20* 30

I will double check this and try to snap a pic to eliminate any doubt.

Ace Taxi · #5 02-22-2009, 04:31 PM

also - the pointer has a flat face on the passenger side, angled face on the driver's side. I am reading the mark that is aligned with the flat face of the pointer. This is the correct reading as I understand it - but I add it here to eliminate all doubt.

Brian Carlton · #6 02-22-2009, 04:53 PM

Quote:

Originally Posted by Ace Taxi

also - the pointer has a flat face on the passenger side, angled face on the driver's side. I am reading the mark that is aligned with the flat face of the pointer. This is the correct reading as I understand it - but I add it here to eliminate all doubt.

Please do two things:

1) Take a good photo of the pointer when the tang is in the middle of the window on the IP port. Please post it.

2) Look at the camshaft.........take the valve cover off if necessary........are the lobes of #1 generally pointing up and away from the valves (valves closed)........or are the lobes pointing downward and both valves are open?

Ace Taxi · #7 02-22-2009, 05:38 PM

Here are the pics

sixto · #8 02-22-2009, 07:05 PM

What DIESELVOLVO said. What you should do, according to me, is align the notch in the cam sprocket flange with the mark in the front most cam tower then look at the crank pulley and read the position. The passenger side edge should be at or within a couple of degrees of 0T. If not, that's a problem. Then, remove the IP plug and watch for the lug to center in the port as you nudge the crank to 15* ATDC. If not, that's a problem.

Sixto
87 300D

babymog · #9 02-22-2009, 07:50 PM

Makes perfect sense AT.
Rotate the engine 1revolution, should have the camshaft at the TDC point and all lined up except the IP.

I don't know if it is possible, can one remove the IP timing device, rotate the pump 180* and reinstall the timing device instead of removing the IP?

sixto · #10 02-22-2009, 11:01 PM

Quote:

Originally Posted by babymog

I don't know if it is possible, can one remove the IP timing device, rotate the pump 180* and reinstall the timing device instead of removing the IP?

You can slip a plastic or metal sheet between the timer and chain then use the timer to rotate the IP by hand. Not sure if anyone is strong enough to do that. Using grips on the timer could damage the centrifugal advance mechanism. Alternatively, remove the timer and use very well padded grips to turn the IP splines. I'll tack JonL's paperweight warning here.

Either way there could be some trial and error because the tensioner has to be out to gain enough slack to lift the chain off the timer.

Sixto
87 300D

JonL · #11 02-22-2009, 08:36 PM

Theoretically, you don't have to do anything with the cam. Just go to TDC with the cam mark aligned (that will be TDC on the compression stroke). Go another 15 degrees. That is where the IP should be timed. Remove the IP, turn it so the tang is centered in the port, install it, and you should be good to go. HOWEVER... there is more to it than just that (of course).

1. I'm not sure if there is anything to be concerned about regarding the timing device and the vacuum pump cam. I'd have to look at the manual, which I do not have here.

2. When you remove the IP, you are supposed to use a special tool called a "centering tool" to hold the pump sprocket in position while the pump is out. I improvised something myself, but I don't want to risk the wrath of the paperweight police. You should get the manual (it is available online at a few places) and study it. I saw the centering tool on ebay for $10 or something really cheap like that.

3. When you remove the IP and set it so the tang lines up, you will need something to hold in position when it is installed. There is a special tool that goes into the port and engages the tang to hold the IP cam in the right position. I made a tool to do this, but once again... there's that whole paperweight issue.

Brian Carlton · #12 02-22-2009, 10:54 PM

Quote:

Originally Posted by JonL

3. When you remove the IP and set it so the tang lines up, you will need something to hold in position when it is installed. There is a special tool that goes into the port and engages the tang to hold the IP cam in the right position. I made a tool to do this, but once again... there's that whole paperweight issue.

I apologize...........you've clearly proven your mettle with regard to the knowledge of these engines.

I have the tool to do this and I've never been successful in using it. Apparently, two people are required to prevent turning the IP notch right through the very tiny notch in the tool.

sixto · #13 02-22-2009, 11:18 PM

Quote:

Originally Posted by Brian Carlton

I have the tool to do this and I've never been successful in using it. Apparently, two people are required to prevent turning the IP notch right through the very tiny notch in the tool.

I'm sure you've figured this out but you have to have the lug already in view and just a little higher than the center of the port before inserting the tool. The difficulty I have is keeping the tool's slot absolutely horizontal. Once the tool bottoms on the lug, a quick nudge of the IP shaft engages the tool.

Sixto
87 300D

Brian Carlton · #14 02-22-2009, 11:20 PM

Quote:

Originally Posted by sixto

I'm sure you've figured this out but you have to have the lug already in view and just a little higher than the center of the port before inserting the tool. The difficulty I have is keeping the tool's slot absolutely horizontal. Once the tool bottoms on the lug, a quick nudge of the IP shaft engages the tool.

Sixto
87 300D

I understand it...........but never accomplished it..........because I'm down by the crankshaft trying to "feel" the engagement at the IP..........never going to happen.

I don't understand why the tool cannot have a deep slot in it.......about 3X deeper than the current "screwdriver" slot.