Removing OM603 IP today - PeachParts Mercedes-Benz Forum

cmac2012 · #1 06-05-2021, 04:41 PM

This from my dead 300SDL while I still have it. I have a buyer lined up. Have the job half done. The vacuum pump, intake manifold, and steel fuel lines are off. I don't guess there's much demand for intake manifolds, trivia note.

I referred to this tutorial:

PeachPartsWiki: Injection Pump Removal

This is the second one I've removed, the first was at Pick n Pull from a 350SD that had been hit way hard in the rear end. We deteremined that it had a 3.0 liter - prolly installed when the 3.5 went bad. It had a #14 head, which a 3.5 wouldn't have.

So here I am again performing surgery on a cadaver. Pretty sure the business about aligning the timing, getting it right before you pull it pertains to needing to put it back into the same car, but I think it might be good to use this as practice. I can't figure out where the timing marks are found to get it at 15 degrees ATDC. Does the valve cover need to come off for this?

I have the vacuum pump off, it's not visible in there is it?

Usaguy · #2 06-05-2021, 04:55 PM

Crank at 15 ATDC If looking into the bolt hole at the back of the ip

Crank at 24 BTDC If you do it by aligning the slot at the front of the ip

15 atdc is on #1 cylinder power stroke and 24 btdc is on compression stroke. You need to remove the valve cover and verify it by looking at the cam ( lobes pointing away from the "lifters" in both cases)

cmac2012 · #3 06-05-2021, 05:20 PM

Are you talking about this view through the bolt hole (this photo from the turorial)?

He mentions this as a way to avoid taking off the valve cover (though he didn't say it that way):

Quote:

Rotate the engine by hand to 10 degrees ATDC (NOTE: you will hope to land at around 15 ATDC but start at 10 so you won't have to back up) and take off the oil fill cap. The reason the fill cap comes off is because you want to be sure it's the compression stroke and NOT the exhaust stroke (the fuel squirts in on the compression stroke). The cam lobes for #1 will be pointing up in the compression stroke (i.e. no valves held open on the number 1 cylinder).

Since I don't need to put it back on, with a new gasket anyway, I might try both methods, that is, take the valve cover off.

Usaguy · #4 06-05-2021, 05:50 PM

Yes that's the hole and you rotate it until it's in the middle. There's also AB light tool for that.

If you can see/feel #1 cylinder cam lobes through the oil fill cap then do it that way but it's safer to just take the cover off.

He also made a mistake saying to be on compression stroke while doing it 15 ATDC method. After Top Dead Center is a power stroke and not the compression stroke.

cmac2012 · #5 06-05-2021, 06:06 PM

I think I agree about taking the cover off. Not sure what can go wrong if you reinstall and try to start with the timing wrong. Somehow I don't think it would be good. Would hate to see a job like that fall to smash owing to not wanting to take the cover off.

Usaguy · #6 06-05-2021, 06:14 PM

Car won't start/run if you set it at the intake stroke(15atdc) or exhaust stroke(24btdc)

But after you install it it's good to verify it again in case something moved as you were installing the ip

cmac2012 · #7 06-05-2021, 06:24 PM

There's a lot I don't yet understand about this. Wrong timing can be disasterous in some scenarios - such as a BMW interfence six being cranked and run just enough off timing to still run and bang valves as well. But there's a lot different in that scenario. I swapped in about 5 or 6 timing belts in my two E30 rigs, so that was something big in my thinking.

Usaguy · #8 06-05-2021, 06:24 PM

Also another tip: if you've gone slightly past the timing mark dont be tempted to just rotate it slightly backwards. That will give you a wrong timing value because of chain play. You have to rotate it almost 720 degrees again in case you go past the mark

tjts1 · #9 06-05-2021, 06:46 PM

Pull the injectors if you got a deep 27mm socket.

cmac2012 · #10 06-05-2021, 10:13 PM

What, to make it easier to rotate the engine? I might do that.

For right now, I’m at a recurring theme in my life, stated best as a question: why are DIY instructions on the web so crappy? I’m trying to figure out how to access that little timing screwdriver looking thing pictured in post #3. I can’t for the life of me determine which nut/bolt he’s talking about. Here’s how he leads up to it:

Quote:

Remove the cover bolt on the side of the IP near the bottom (17mm I believe). Look inside and you should see a flat head screwdriver looking blade which is the IP's timing slot that mates up to the IP timing tool locking the IP in place.

People sometimes complain about pelican part’s DIYs, but the photos they generally provide with an arrow pointing to the part in question are pretty damned useful. “Cover bolt on the side of the IP near the bottom??” What the hell does that mean?

cmac2012 · #11 06-06-2021, 02:28 AM

Having calmed down a bit, there was some useful content in that DIY. Imagine we had none of that stuff. The Haynes manuals are weak. With my E30 I at least had the Bentley manual.

I found the bolt he referred to. When I first took it off, I'm thinking this must be it. There was a cavity in the center of it, so as to accomodate that screwdriver looking thing.

But I couldn't see anything in the hole with my inspection mirror. Then I looked at his photos again and got a better idea of what he was showing, I took the bolt off again and managed to see the small tab in question. It's not as well centered on mine as on his. Not sure what the upshot of that would be.

I took the valve cover off and THAT is one impressive looking camshaft. Like sculpture. I found the timing mark and oddly enough, I was very close to where I needed to be. And neither lobe was suppressing a valve.