1992 300SE Head Gasket - PeachParts Mercedes-Benz Forum

ehopkins · #1 04-06-2009, 10:54 AM

Hello all,
I recently purchased a 1992 300SE with a known head gasket issue. It is the M104 motor with the dual overhead cams. I'm currently in the process of replacing the head gasket. My problem is that the cams are not lining up so that I can place the 4mm rods to keep the cams aligned when the head is removed. I have confirmed that I am at TDC on the compression stroke but only the intake cam lines up. There are signs that someone has tried to stop an oil leak at the front cover. Whold it be safe to assume that who ever worked on the car did not get the cams lined up properly? Where should I go from here?

ehopkins · #2 04-06-2009, 03:45 PM

Can anyone please advise?

Gilly · #3 04-06-2009, 05:43 PM

At this point is the head on or off or where are you on the process? Is the chain tensioner still in place? At this point if you are disassembling the engine (getting ready to pull the head) it shouldn't matter if the pins are in or not.

Gilly

ehopkins · #4 04-06-2009, 05:53 PM

Head is still on the car and the tensioner has not been removed yet. Everything that I've read (from a couple of sources) says that you need to be at TDC on the compression stroke then mark the position of the cams in relationship to the chain and then insert the 4mm pins so that the cams don't move for the reinstall.

Gilly · #5 04-06-2009, 06:41 PM

How close are you on the exhaust cam (how close is the pin to dropping in to the hole)?
Gilly

ehopkins · #6 04-06-2009, 06:59 PM

Not by much even if I try backing it off from TDC still no luck.

Gilly · #7 04-06-2009, 07:19 PM

OK, there is a hex shape on the cam, I think towards the back, you can stick a wrench on that and twist the one cam, probably be better to take the chain tensioner out first.
Gilly

ehopkins · #8 04-06-2009, 07:24 PM

Yes, I know about it. It is on the exhaust cam. Moving the exhaust cam with the chain still in place wouldn't that move everything with it? i.e. intake cam and valvetrain and the crankshaft and rotating assembly?

engatwork · #9 04-06-2009, 07:34 PM

Excuse me for not remembering it right off the top of my head but aren't there some marks on the cams? How far off are they?

ehopkins · #10 04-06-2009, 07:35 PM

Basicly, what I am asking is can I or would it be advised to remove the head as is. With a pin in the intake side then position the exhaust cam to where it should be during assembly?

engatwork · #11 04-06-2009, 08:15 PM

It would not stop me from pulling it off. Has the chain tensioner been removed?

Gilly · #12 04-06-2009, 08:16 PM

If you take the tensioner off, you will have some slack in the timing chain, if you are off a tiny bit you should be able to get the pin in the exhaust cam(without making any thing else move). The holes the pin goes in and the top surface of the head (that the pins rest against) are the official cam timing marks.
Gilly

Gilly · #13 04-06-2009, 08:20 PM

As long as you get it back together where it should be I wouldn't agonize over getting the pins in now. AS LONG as they are both close now, if you are way off, then there is the possiblity the crank is actually at TDC but not on the compression stroke. And actually, I guess even that wouldn't matter as long as you put it back together as it should be. You also have to be careful about getting the intake sprocket on correctly relative to the cam (due to the solenoid for cam advance)

Gilly