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Old 01-13-2007, 06:52 PM
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Join Date: Dec 2006
Location: Boston, MA
Posts: 27
Unhappy Trouble turning engine during valve adjustment

Hey guys,

I finally had the time and the weather to do my very first valve adjustment. I have a 1980 240D. I downloaded the instructions from Diesel Giant and went at it. The problem is I couldn't turn the engine. I was turning the power steering pump bolt as it said in the instructions, but I could only get the engine to turn the slightest bit and then when I'd take the wrench off the bolt to reposition it, the engine would rock back to where it was. I tried for over an hour and didn't get it to turn more than a couple degrees. I finally had to give up and put everything back together. I'm terribly frustrated. What is the problem?

Also, just for the sake of argument.....suppose one of the lock nuts on one of the valves was loosened and the top nut wasn't tightened down on to it. What would happen if the car were run?

1980 240D 4-spd 185K (The Tooter)
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Old 01-13-2007, 06:59 PM
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Join Date: Jan 2002
Posts: 18,355
Sounds like you had a manual transmission car still in gear. Did you try turning it with the starter with the shut off valve pushed down?
1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13
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Old 01-13-2007, 07:02 PM
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Join Date: Feb 2002
Location: Virginia
Posts: 550
A 27mm socket on the crankshaft is the best way to turn the motor. You may need to remove the fan to turn it. If you dont have/can't find 27 mm a 1 1/16 socket is virtually the same thing. You also may use a remote starter or jumper wire in a real pinch. Just snug the lock nut down first...why in the world wouldn't you?

82 300 SD
77 450 SL (gone)
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Old 01-13-2007, 07:21 PM
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Join Date: Dec 2006
Location: Boston, MA
Posts: 27
D'oh! Manual transmission in gear. I'm an idiot. Didn't say anything about that in the instructions!

As for not tightening the valve adjusting nut onto the lock nut, I ask because I may have forgotten to do that on one valve. Even though I couldn't turn the engine, one valve was in proper position to adjust and so I tried to adjust that one. I was having a hell of a time getting the wrenches in there and kept having to reposition myself. During one of my repositionings, I ended up with the wrenches on a different valve by accident. I may have loosened the lock nut a bit on that one before I realized it was the wrong one. I didn't bother to check it to to see if I had indeed loosened it because I was going to get to that one eventually for adjustment. But then I couldn't move the engine and never got to any of the other valves. I put everything back together, cleaned up, and then remembered that I might have loosened that other valve's lock nut. So I ask because I want to know if I should not run the car until I get back in there and tighten up that lock nut. I'm not certain that I actually loosened it, but it's certainly possible and I don't want to take any chances.
1980 240D 4-spd 185K (The Tooter)
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Old 01-13-2007, 07:27 PM
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Join Date: Mar 2006
Location: minnesota,hey.
Posts: 1,840
may as well redo it, and finish the job. FWIW< the FSM states 2 ways to turn engine. the crank nut-27mm, and using a remote starter switch. I built one for less than $10. makes it easy. done w/ a valve, reach over and hit the button. next. It does not recommend the PS bolt. It is your car, so whatever...

since you have a stick, you can also jack up 1 tire and turn that to rotate engine(not in the FSM)
1984 123.193 372,xxx miles, room for Seven.

1999 Dodge Durango Cummins 4BTAA 47RE 5k lb 4x4 getting 25+mpgs, room for Seven.
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