[anorphirith]

Hi, I'm planning to clean my intake valves soon, how do you rotate the engine on an automatic transmission?
thanks

[TT-Tom]

Originally Posted by anorphirith

Hi, I'm planning to clean my intake valves soon, how do you rotate the engine on an automatic transmission?
thanks

Put it in neutral and turn the crank bolt

[BMWM.D.]

Originally Posted by TT-Tom

Put it in neutral and turn the crank bolt

Actually doesn't even have to be in neutral. The flexplate and torque converter can rotate in park.

And yeah, It's either a 21mm or 22mm socket. Having slight memory loss on that one....

[anorphirith]

where is the crank bolt ?
also what will happen if I get some carb cleaner into the cylinder when I restart the car ?
thanks

[raceyBMW]

You will probably need to pull the spark plugs too...otherwise it will be very difficult to crank. The crank bolt is on the front of the engine, at the center of the largest pulley.

Honestly, not to be an ass, but if you don't know where the crank bolt is, this may not be a job you should tackle on your own. There is no issue getting some carb cleaner in the piston chamber, it will just burn off....as long as its not a ton, because you could hydrolock if its too much (that would be hard to do)

[E90Company]

Originally Posted by raceyBMW

You will probably need to pull the spark plugs too...otherwise it will be very difficult to crank.

Not when the IM is off.

[The Ghost]

Originally Posted by raceyBMW

You will probably need to pull the spark plugs too...otherwise it will be very difficult to crank.

Nah, it will turn over by hand with a long rachet.

[Cripple]

Originally Posted by anorphirith

where is the crank bolt ?
also what will happen if I get some carb cleaner into the cylinder when I restart the car ?
thanks

Serious... or troll?

[Bimmer305]

Use a remote starter switch. Easiest way.

[Tony@vargasturbotech]

Originally Posted by raceyBMW

You will probably need to pull the spark plugs too...otherwise it will be very difficult to crank. The crank bolt is on the front of the engine, at the center of the largest pulley.

Honestly, not to be an ass, but if you don't know where the crank bolt is, this may not be a job you should tackle on your own. There is no issue getting some carb cleaner in the piston chamber, it will just burn off....as long as its not a ton, because you could hydrolock if its too much (that would be hard to do)

Truth, you can easily do more harm them good if you are asking these questions and about to start taking your motor apart. Just pay someone to clean them for you.

[MilehighM3]

Originally Posted by Bimmer305

Use a remote starter switch. Easiest way.

Exactly

[JC335xi]

+1

This is what I did (kinda, just rigged it up with stuff I had laying around the garage). Quick and easy.

[MDORPHN]

Originally Posted by Vargasturbotech

Truth, you can easily do more harm them good if you are asking these questions and about to start taking your motor apart. Just pay someone to clean them for you.

+1

Neil

[TexE90]

Remove radiator fan and use a 23mm socket (going off memory, I don't think it was 21 or 22mm but 23mm). Radiator fan is one torx bolt on the passenger side of the fan near the hood, one torx on the drivers side underside of the fan where the heat exchanger mounts to the fan, and one clip on the drivers side about 60% of the way up the fan.

You'll need a long ratchet or what I did is buy a long metal pipe that I put on the end of my ratchet. The valves sit at top dead center for quite a few cranks before finally pushing down and opening. I would always make sure to open the valves, close them, and then give it one or two more cranks to ensure top dead center.

[raceyBMW]

Originally Posted by E90Company

Not when the IM is off.

How does that help you? The valves are still there, it doesn't matter one bit whether or not the intake manifold is on or off.

Some say they can get it to turn with a big breaker bar or pipe, but it would make your life a lot easier if you took the plugs out to hit TDC so there is no compression in the cylinder and much less resistance to turning the crank bolt. I have not yet done this myself, but I am using my experience on other cars trying to turn the crank bolt.

[j_syk]

Hopefully this wasn't the wrong way, but I just disconnected all the coils and hit the start button. I got really lucky, When I first got to the valves, I had 3 closed. After cranking it, I had the other 3 closed on the first attempt.

[PichaDis11]

Holy revival. Is this rotation clockwise or anti-clockwise?

[mweisdorfer]

Originally Posted by PichaDis11

Holy revival. Is this rotation clockwise or anti-clockwise?

I usually go clockwise.

[PichaDis11]

Originally Posted by mweisdorfer

I usually go clockwise.

Clockwise it is.

[mweisdorfer]

Originally Posted by PichaDis11

Clockwise it is.

Yep, if you go counter-clockwise you risk loosening up the crank bolt, which would not be good. The Likelihood of that happening isn't real high, but why risk it.

[PichaDis11]

Originally Posted by mweisdorfer

Yep, if you go counter-clockwise you risk loosening up the crank bolt, which would not be good. The Likelihood of that happening isn't real high, but why risk it.

Read that if going counter-clockwise would allow the engine to skip timing of some sorts. Not sure the accuracy of that though. Bentley and repair info from newtis both mention of turning the crank in the direction of rotation.

[dpaul]

Originally Posted by PichaDis11

Read that if going counter-clockwise would allow the engine to skip timing of some sorts. Not sure the accuracy of that though. Bentley and repair info from newtis both mention of turning the crank in the direction of rotation.

If things were that fragile, we would all have destroyed our engines long ago.

Also, if you have ever tried to loosen that crank bolt, you would note that it takes a whole lot more force than what is required to rotate the engine, even with the spark plugs still in place. Loosening the crank bolt is not really much of an issue if you wished for some reason to reverse rotate the crank.

However, it you were setting the cam timing, you would want to rotate the engine in direction it operates so that tolerances in the chain and tensioning system would not become an issue. Similarly, if you are looking for TDC, you want the piston to approach in the same manner that it would during normal operation.