Is there something someone should be afraid of if turning the crank in the opposite direction?

 

ive never heard of that. ive spun a honda engine clockwise with no problems at all, in fact, the apexi integra spins backwards to mate to a special tranny. whoever told you that is wrong as far as i know........ somebody prove me wrong

 

Well I thought it might sound bogus too, but I just want to be sure..

There's a few know-it-alls in my auto class, who are always yapping about stupid ****.

Maybe this applys to 6-8-12cyl engines...

 

Yeah I got that same problem.

 

ha ha, same here. do what i do. just sit back, quietly laugh to yourself at what they say, and know the truth- you know much more than they do.

 

There's no oil pressure when spinning backwards. Of course hand cranking it backwards is no big deal, but you really wouldn't want to spin the motor with a starter motor backwards a lot, as you'd fry the oil pump and bearings. Not to mention the effects on the water pump.

 

It's because the belts are tight on one side, loose on the other, so when you spin the motor backwards, the belts can jump teeth.

 

if your tensioner's tight enough, shouldnt the belt be equally tight on both sides??? i always try to get all of the slack out of both sides before i tighten the tensioner.

 

No, it won't be equally as tight.
When I said loose, I meant loose compared to the other side.
I've turned engines backwards (engines on stands at my engineering school) and none of the teeth jumped, but it is possible.

 

The side that's transferring power will be tighter.

 

I talked to my instructor about this today, he said it's not a real big deal, especially on a 4 cylinder. He mentioned the timing belt/chains are tighter on one side, and when you put more tension in the opposite direction, it changes..

Like that ^

The only reason you would really need to go backwards anyways is to find TDC the oldschool way (by placing something long in the spark plug hole and watching the piston move it), or if you passed it when lining up marks.

 

How about on a rotary motor?

 

well exhaust and intake ports would switch roles so you'd be pulling air out of your tail pipe and putting the exhaust out your intake