OK - tomorrow I will do the following:

1.) I will reposition the camshaft 180* as discussed.

2.) I will then line up the tang on the IP and remove the IP in that position per the DIY instructions

3.) I will then turn the engine to 15* ATDC and re-install the IP.

What am I overlooking?

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Josh
Ace Taxi
Bangor, ME

Cab 2: '87 300D
Cab 3: '92 300D
Cab 4: '90 300E 4Matic Wagon
Cab 6: '96 E300D
Cab 7: '87 300TD
Cab 8: '91 300E 4Matic Wagon
Cab 9: '98 E320 4Matic Wagon
Cab 10: '98 E300D
Cab 11: '98 E320 4Matic Wagon

'96 Suburban 6.5 Turbodiesel

If you are sure that the camshaft is in proper alignment with the crank..........the notch on the tower is aligned when the engine is at 0 degrees..........then you don't need to move the camshaft again. We had some misunderstanding from your original post as to the position of the camshaft relative to the crankshaft. Was it OK originally.........or is it OK now?

Turn the engine so that the IP lug is in the port window and remove the IP.......carefully, so it doesn't rotate.

Rotate the engine so that the damper reads 15°ATDC on the compression stroke (cam lobes basically upward).

Reinstall IP.

Check IP timing again.

I am a little confused on this point myself. Maybe you can clarify it for me.

When we changed the TC originally, I believe that the cam lobes on #1 were at "10 & 2". Then we turned the crank one rotation, reopened the TC and turned the camshaft 180* - because we thought it would fix the IP timing problem (let's not go there again).

My understanding is that the crankshaft turns 2x for every 1x of the camshaft. Even if the cam mark and the mark on the #1 bearing cap line up at 0*TDC, how can I be sure #1 piston is the top of the stroke & not the bottom? I don't want to be half a cycle out of phase again.

__________________
Josh
Ace Taxi
Bangor, ME

Cab 2: '87 300D
Cab 3: '92 300D
Cab 4: '90 300E 4Matic Wagon
Cab 6: '96 E300D
Cab 7: '87 300TD
Cab 8: '91 300E 4Matic Wagon
Cab 9: '98 E320 4Matic Wagon
Cab 10: '98 E300D
Cab 11: '98 E320 4Matic Wagon

'96 Suburban 6.5 Turbodiesel

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?

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Gone to the dark side

- Jeff

If the mark on the #1 bearing cap aligns up with the mark on the cam and the crankshaft is at 0°, there are only two possibilities:

1) The #1 piston is at TDC on the compression stroke.

2) The #1 piston is at TDC on the exhaust stroke.


In the first case, the cam lobes are pointing generally upward and the valves are closed.

In the second case, the cam lobes are pointing downward and the valves are open.

If you've got the first case, you don't need to bother with the camshaft.

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.

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1987 W201 190D

And in the second case, the cam is mismarked. There is no second case. The mark only lines up when the valves are closed, i.e. cam is at TDC on the compression stroke.

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1987 W201 190D

When you remove the IP, the IP cam WILL rotate. You need a special tool to hold it in position. The plunger springs in the pump will push on the cam and turn it away from that 15 ATDC installation position. It will not stay there by itself.

Agreed that the if the cam mark is aligned with the bearing cap mark when the crank pulley reads 0T you do not need to change it again, even if you changed it before. Once you retime the IP, the engine won't know that the cam was ever changed.

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1987 W201 190D

In theory, yes...........but he turned the cam 180 degrees..........where was the mark prior..........where is it now?

Let us leave no stone unturned at this point...........

I wasn't aware of that. It complicates the situation without the locking tool.

It's going to have to be a bit of trial and error, I'm afraid.

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.

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

I'm not sure how necessary this is if we're talking about the same tool. The tool I'm thinking of requires removal of the IP then installation of the tool. Since there's a time neither the IP nor tool is touching the timer, I conclude the tool is not mandatory if you don't turn the crank or release the tensioner.

When I removed an IP to replace the big o-ring, I left the timer hanging on the chain with zip ties. The zip ties were optional. The timer wasn't going anywhere and neither was the chain. I didn't remove the tensioner.

Sixto
87 300D

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.