OM603 Valve Seal Replacement and Each Piston TDC - PeachParts Mercedes-Benz Forum

oilslick · #1 11-12-2017, 05:52 PM

I’m replacing the valve seals in my OM603. I’ve already replaced them in cylinders 1 and 6 since they are at TDC to start with. Is there any number of degrees of rotation that I can follow per cylinder to change the rest of them so the piston will be at the top? I don’t really wanna get out the air compressor and use that method. I also have the cam sprocket set up to rotate as the crank rotates. If I can get the piston at the top of the cylinder with some degree of confidence then I’m golden.

dieselbenz1 · #2 11-12-2017, 06:29 PM

diesel300 just posted how he accomplished this

Mxfrank · #3 11-12-2017, 06:30 PM

If you start at TDC compression for cyl 1, then every 120 degrees gets you to TDC compression on the next valve in the firing order. If the valve drops, you can probably reach in through the port to lift it back up.

oilslick · #4 11-12-2017, 06:48 PM

Quote:

Originally Posted by dieselbenz1

diesel300 just posted how he accomplished this

I will look it up! Thanks!

oilslick · #5 11-12-2017, 06:48 PM

Quote:

Originally Posted by Mxfrank

If you start at TDC compression for cyl 1, then every 120 degrees gets you to TDC compression on the next valve in the firing order. If the valve drops, you can probably reach in through the port to lift it back up.

Good info! Thanks so much!!!

Diseasel300 · #6 11-12-2017, 07:16 PM

I took a string and wrapped it around the crank balancer and marked it at TDC. Took the string back off and marked it into 3 even sections and wrapped it back in the original position. Took a file and made marks to match the string so I knew where the 120 and 240˚ marks were. Worked like a pro. Make sure you have a helper keep tension on the chain and sprocket as you turn the crank. Beware of the spring on the vacuum pump, it will suddenly want to suck the chain in all at once!

oilslick · #7 11-12-2017, 09:19 PM

I found your thread explaining it. Good info.

Diseasel300 · #8 11-13-2017, 07:06 AM

I couldn't come up with any better way to do it. Those collets on the valve stems are on there TIGHT. Air pressure will NOT keep the valves in place, I tried it. They need a gentle pop on the piston face and they come right out. Short of pulling the head, there's no other way to do it and the 120˚ and 240˚ marks are not marked on the crank pulley or damper (opportunity lost there!)