HELP! Turned engine by hand, not sure of direction.
 

Last night I started to do AT Fluid/Filter change. I turned the motor with a screwdriver on the flywheel teeth, to get to the converter drain plug. Today I read about possible damage by turning the motor the wrong direction. I don't have a clue which direction I turned it. Have not yet started it. Now afraid to.
PLEASE HELP THIS IDIOT!

Thanks in advance,

Looking at the car from the front, you turn via the nut on the end of the crankshaft. The proper direction as seen from the front is clockwise. On the 6 cyl. M103 motor, this nut uses a 27MM socket. Not sure about other 126 cars.

I cannot speak for going the wrong way on MBs, but when this is done on Asian models with rubber timing belts, you'll sometimes cause the belt to jump one or more teeth, thereby throwing off the valve timing.

What now?
 

Having already turned the motor about 1/4 turn, can I correct any possible damage by now rotating the crank cw?
Will I have to strip off the valve covers to check if I've jumped a tooth?
I am sooooooo stupid!!

Thanks again,

SuperSyn Mobil I
 

Has anyone else recived an e-mail from Mobil/Exxon about their new Super Syn Mobil I?

P E H

BigMiket57,

I hope someone who knows better jumps in and explains why not (added not in edit), but if you want to run the car now, I say go ahead. I believe the issue with MB's and turning them the wrong direction has to do with timing the car. If you turned the engine half a turn or so and just want to run it now, I do not think there is a big deal. I have had the my cars roll backwards in gear (like 4th or 3rd on my 240D and 5th or 4th on my 190E) and never thought twice about starting it up afterwards. And never developed a reason to either. So, my personal experience says it is not a running concern, but I can see how the chain tension might change if you do this when you are lining up timing marks and the ones you can't see could be off significantly. Resetting them and then running the engine in the other direction would then lead to timing problems.

Good luck and I hope this helps! Jim

BigMike:

I'd like to tell you all is well, but I'm not sure if anyone can really safely say that.

To know for sure, you'd need to take off the valve covers and ref. index marks on the cams with the crank when this is lined up with that, etc., etc.

Hopefully someone versed in the 420SEL will chime in with their 2 cents.

The above post about Mobil I was supposed to be a new post. I clicked the wrong button. I will repost as a new topic.

BigMikeT57,

You didn't say which engine (motor is incorrect) you turned backward. If it is a Diesel and you can turn it forward (2 complete revolutions), without the valves hitting the pistons, you haven't jumped the timing because on a Diesel if the timing chain jumps one tooth, the valves will hit the pistons. As long as the valves clear the pistons, it won't hurt to start the engine. If it runs as before, the injection timing didn't jump. If it doesn't run as before, you should retime camshaft and injection pump to the crankshaft.

My quess it that you won't have problem.

I'm not sure if the pistons will hit the valves on a gasoline engine with one jumped tooth. So the above test might not work for a gasoline engine.

Always turn the engine 2 revolutions in the direction of travel by hand if there is any question about timing. Even cranking the engine with the starter will break parts if valves hit pistons.

P E H

Many thanks!
 

This is the 4.2 gas engine. I will try turning it over 2 rev's by hand as suggested, while keeping an eye on this thread for any furthur advise.

Thanks again, you've saved me much mental anguish!

BigMikeT57,

I sure hope things come out fine for you as I cannot believe teaching my daughter and two sons to drive manual transmission equipped cars was so potentially dangerous to the engine. All along I thought the real danger was to the clutch! Each of them has done some really spectacularly difficult things to repeat at stop signs on hills. They always just restarted the cars and had no problems (with the engines, that is), and I cannot believe that was just luck. What you did by hand cannot even approach what they did (of course I was a quick learner and did nothing to stress out my Dad when he taught me....) in terms of generating potential to pop the chain or jump a tooth. Good luck, Jim

Mike,

You can pull the fan to gain easy access to the crank bolt, or try to access it (tight fit) from beneath. Should be a 27mm on your car. You'll need the socket and a short extension for the ratchet. Standing at the front of the engine, try turning the engine over (as if you were trying to tighten the crank bolt) through the two complete revolutions.

Chances are 1/4 turn didn't hurt anything, but be sure by rolling it over manually. The V-8s are as tight on the interference as the diesels, and jumping a tooth will bind things up. If you jumped a tooth, you will not be able to turn two complete revs.

If you were prying the flywheel up, from the right side of the bellhousing, that should have been turning the proper direction.

What a relief!!!
 

Rotated the engine 2 full rev's last night without any problem.
Started her up, and all is fine.

Many thanks to all who chimed in.
It is great to have such a deep well of knowlege and experience,
AND are willing to help those less informed.

Many, many THANKS!!

I am now in the process of writing "I will not turn the engine counter-clockwise" 1000 times on my garage wall.

Regards,

BigMikeT57,

Be careful, from the driver's position the engine does turn counterclockwise.

So you better write: "I will not turn the engine in the wrong direction". I'm also glad you calling it an engine, not a motor.

I had a '59 180D, a push rod engine, and it had a flapper valve in the intake air horn to prevent the engine from running backwards if roll started in reverse. The engine would intake thru the exhaust pipe and blow exhause thru the air cleaner. Only damage was the oil pump would run wrong way so there was no lubrication oil getting to the to the engine. So the flapper valve in the intake stream would close and not allow the engine to run backwards.


P E H