No, I didn't do it; I'm just wondering :D : Does an engine get damaged from being cranked the wrong way? I don't mean like, say, being towed (facing forward) in reverse for 50 miles; just something like having it roll backwards down the driveway while in a forward gear, or rotating the flywheel in the wrong direction while the tranny's off; that sort of stuff.

CJF

After thinking sbout for a while, the only thing I can think of would be the oil pump turning backwards also. That may be the only problem

the only time you will run into problems turning an engine the wrong way is if the timing chain or belt is designed only to turn one way.

i dont think the oil pump would care too much

engines that i know of are 22r series toyota motors, the chain tensioner isn't designed to work backwards, damage will occur

most every other pushrod engine i wouldnt worry about

engines that i know of are 22r series toyota motors, the chain tensioner isn't designed to work backwards, damage will occurEven those, rolling the engine backwards a few revs wouldn't hurt a damn thing. The engine goes backwards a little bit, enough to push the chain tensioner in all the way, half the times you shut it off. It's no big deal :smokin:

one street sweeper we have it's a line 6 ford will run backwards once in a while if it back fires while starting it will turn backwards for a few seconds untill i shut it down

we had an old two stroke fire engine, i believe it was a diesel, and if you let off the starter before it fired, sometimes the compression would kick the pistons back down and it would run in reverse. had several people fly backwards into stuff when they put it in 1st and dropped the clutch.

wow, what a cool thread--
Of course an engine can run backwards, just look at a Honda, engine turns Counter Clockwise all the time. Can be confusing.
I've even heard of an engine that could reverse its rotation instead of having to use a reverse gear--but I think that's a bunch of crap. And by a bunch, I mean like a truckload.

The M127, M129, and the M130 Mercedes motors have hydraulic chain tensioners and definitly don't like to go backwards. Some of these engines are used in Unimogs and you can be rolling backwards in a forward gear with the clutch in and pop the clutch and make the engine turn backwards and the chain can jump teeth. Definitly a unique situation, more likely someone doing repairs could turn the engine over backwards by hand and do the same thing. Newer 2- stroke Ski- Doo snowmobiles actually change timing and insantly run backwards for reverse, The system works very good on the snowmobile. Also older industrial engines that were commonly used in marine applications ran "backwards" by using a different cam. We found this out putting a rebuilt engine in an old Chris Craft and we had to switch out the cam to get it to run the correct direction for the boat. A 4 stroke engine will have a hard time running backwards because of the cam.

ah, so it's not a bunch of crap, I stand corrected

Cool stuff. Thanks guys!! :D

CJF