i just removed the cylinder head from my 603, before removal i alligned the cam with the mark on the cap, i assumed it was tdc for cylinder #1 coz both valves were closed, compression stroke.

anyway, i noticed that cylinders 1 and 6 were almost flush against the top of the block, while all the rest were well below the top of the block but were all level? is this normal? i would assume that they'd be at different levels, they differ only by a millimeter i think.

comments? opinions?
thnaks guys!

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85 190E 2.3(SOLD)
86 230E (-->300D) sold
87 300D (-->300TD) sold
68 250S w/ a 615 and manual tranny (RIP)
87 300TD (SOLD)
95 S280 "The KRAKEN" (Turbo 2.9 602 transplant) traded
86 190E 2.3... current project

This is correct. 2 cylenders are on TDC, #1 on thecompression stroke, #6 is on the exhaust stroke.
2 and 5 are on the way up with #5 starting the compression stroke and #2 starting the exhaust stroke.
3 and 4 are on their way down with #4 on the power stroke and #3 on the intake stroke.
I think I got that right.

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84 500 SEL (307,xxx miles)

A normal straight six engine fires on each cylinder every 120 degrees of crank rotation. So, when one cylinder is at TDC (#1) on the compression stroke there will be another cylinder (#6) that is at TDC on the exhaust stroke.

At this exact point in time there will be another cylinder (#5) that is 120 degrees before TDC on the compression stroke. There will also be another cylinder (#2) that is 120 degrees before TDC on the exhaust stroke.

Also at this exact point in time, there will be another cylinder (#4) that is 120 degrees after TDC on the compression stroke (the power stroke). There will also be another cylinder (#3) that is 120 degrees after TDC on the exhaust stroke (the intake stroke).

The interesting thing is that the piston heights of cylinders 2,5,3,and 4 are all the same. 120 degrees before TDC is the same height as 120 degrees after TDC.

I'm sure that it looks quite strange, but it's normal.

WOOHOO!

thanks guys! i actually understood what you said! about the 120 degree thing, coz as i understand there are 2 crankshaft revolutions per complete firing order. haha, i got confused somewhere along the line that's why i panicked a bit and thought maybe i had bent rods or something! i didn't realize that if there are two cylinders at tdc, which means 2 con rods are vertical, the other pair at 120 degrees would be forming the "Y" which means they would be perfectly level with eachother. i've got a big smile on my face right now coz i don't have bent rods! AND, i actually understood the explanations.

hehe, i wish i could've read this 15 minutes earlier, coz i went out and turned the crankshaft to check if all the pistons reached tdc. i had someone pull on the cam pulley to keep chain tension.

thanks guys! whew!

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85 190E 2.3(SOLD)
86 230E (-->300D) sold
87 300D (-->300TD) sold
68 250S w/ a 615 and manual tranny (RIP)
87 300TD (SOLD)
95 S280 "The KRAKEN" (Turbo 2.9 602 transplant) traded
86 190E 2.3... current project

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