Engine rotation

[dieselmania]

Is engine rotation direction viewed from the flywheel end? If the 603 is a clockwise engine, then the flywheel turns clockwise as viewed from the driver's seat, correct?

[97 SL320]

I'm not sure if there is a standard other than the convention we assume.

For most engines, yours included, when viewed from the crank _pulley_ the rotation is Clockwise. When viewing this same engine from the _flywheel_ it is Counter Clockwise.

There are few engines that have reverse rotation, motorcycles usually are, one engine of a twin engine boat / aircraft and, owing to their motorcycle origins, most Honda cars.

[dieselmania]

well then that means I rotated my engine the wrong way, I turned it CCW for several revolutions with the crank pulley nut.

[pawoSD]

Originally Posted by dieselmania

well then that means I rotated my engine the wrong way, I turned it CCW for several revolutions with the crank pulley nut.

That is REALLY not good. Its clockwise from standing in front, so it should rotate towards the drivers side. There's the possibility you messed up the timing chain by going backwards. I would rotate it several times in the correct direction by hand to make sure it is all still turning correctly without anything clanking or hitting in the right direction before trying to start it again.

[dieselmania]

I just went out there and rotated it around 3 times, everything seems fine, smooth and no noises. One thing I took advantage of is the fact that I have the vacuum pump off, I checked the timing marks after my CCW rotation, then I carefully and slowly began a controlled CW rotation until I saw the timing device begin to move. It was at about 2 degrees into the CW rotation. Sort of a red neck timing chain stretch check, like we used to do on the gassers by watching the distributor rotor. Whuddya think?

[pawoSD]

That was probably just due to chain slack retightening, not an accurate way to check for chain stretch. Hopefully everything is still properly in sync....you'll find out when you start it.

[tyl604]

Let us know what happens.

[qwerty]

Originally Posted by dieselmania

Is engine rotation direction viewed from the flywheel end? If the 603 is a clockwise engine, then the flywheel turns clockwise as viewed from the driver's seat, correct?

If it was a clockwise engine, that would be correct. But it's a CCW engine.

Originally Posted by 97 SL320

I'm not sure if there is a standard other than the convention we assume.

The SAE convention uses the flywheel to define direction.

[rscurtis]

Virtually all engines turn CCwise on the PTO end. The exceptions are chain saws and some vintage English cars. Wisconsin also made a reverse-rotation engine for use on tile saws.

[dieselmania]

Originally Posted by qwerty

If it was a clockwise engine, that would be correct. But it's a CCW engine.



The SAE convention uses the flywheel to define direction.

That is what threw me off. I assumed everyone used the flywheel view to determine rotation, just like we use the driver's position for right and left.

[qwerty]

Originally Posted by dieselmania

That is what threw me off. I assumed everyone used the flywheel view to determine rotation, just like we use the driver's position for right and left.

For some strange reason, a large percentage of the population finds the need to proceed to the front of the vehicle, do an about face, and then procede to reverse the meanings of left and right in a manner which can reasonably be described as totally assinine. By their logic, the steering wheel is on the left side of the vehicle, except when moving in reverse.

[4x4_Welder]

For everything except engine rotation, it is oriented as sitting in the car. For engine rotation, that is as looking at the front of the engine.
Hondas and some Mitsubishis have reverse rotation.

[qwerty]

Originally Posted by 4x4_Welder

For engine rotation, that is as looking at the front of the engine.

Not according to the Society of Automotive Engineers.

Does it make the slightest bit of sense to ignore the output end and classify direction by the accesorry drive rotation?

[4x4_Welder]

Originally Posted by qwerty

Not according to the Society of Automotive Engineers.

Does it make the slightest bit of sense to ignore the output end and classify direction by the accesorry drive rotation?

That is the SAE standard, not what automakers actually use. I have seen people have a hard time figuring out which way to turn a bolt on the other side of something (think brake caliper bolts), I can't imagine telling someone "well, it rotates counter clockwise looking from the opposite end" and have them be able to figure it out. Automakers just make it easy and say "clockwise".

[dieselmania]

Thanks for the replies which made it clear that the vast majority of mechanics view engine rotation from the front, which is what I was trying to find out.
treetrimmer, I have been monkeying around under the hoods of my own vehicles for 40 years, don't think I'll be stopping anytime soon, I enjoy it too much.