Author Topic: engine play while hand cranking? ??? (Read 2380 times)

n2motorsports · « **on:** June 12, 2011, 11:19:33 AM »

Recently found a good deal on a 94 m42 motor. Engine had 120k on the clock and was already removed from car. We handcranked the motor and everything sounded nice, except at the same spot we had a very noticeable deadspot. Isn't there supposed to be slight resistance the entire revolution? Chain and cams looked good. Possibly a chain tensioner or something wrong with crank?

bmwman91 · « **Reply #1 on:** June 12, 2011, 12:11:14 PM »

You should feel a fair amount of resistance building up as you push a cylinder through its compression stroke, and then it should almost turn itself 90 degrees as you move it through its "power" stroke, before another cylinder starts its compression stroke. All the while you should hear slight hissing sounds as the air blows by the piston rings in the motor. Turning it over by hand is supposed to feel "lumpy" like that.

n2motorsports · « **Reply #2 on:** June 12, 2011, 04:17:17 PM »

Quote from: bmwman91;104515

You should feel a fair amount of resistance building up as you push a cylinder through its compression stroke, and then it should almost turn itself 90 degrees as you move it through its "power" stroke, before another cylinder starts its compression stroke. All the while you should hear slight hissing sounds as the air blows by the piston rings in the motor. Turning it over by hand is supposed to feel "lumpy" like that.

Thank you so much. If you're ever in San Diego let me buy you a beer.

bmwman91 · « **Reply #3 on:** June 12, 2011, 07:59:40 PM »

I may actually hit you up for that later this summer. I drive down there periodically to help my fiancee's younger sister move at the end of the school year at UCSD. I have been meaning to get down there to do some rock climbing too.

91 e30m42 · « **Reply #4 on:** September 13, 2011, 06:44:07 PM »

bmwman91 where exactly in the bay area do you live in???