How to find out if my crankshaft is broken?

[splitsecondcb]

okay i turn the key to ignition and the car turned and not cranking just free spinning, also its not turning my timing belt, the flexplate and torque converter turn but not sure if my crankshaft is turning. a friend of mine said take off the oil pan and i can see the crankshaft, is this the first thing i should do to see if my crankshaft is broken? want to make sure before i get in to deep with this engine its a sohc f20a.

[deevergote]

A broken crankshaft is VERY unlikely... however, if the timing belt isn't turning, it's possible.

Check compression on all cylinders. If nothing happens in a cylinder, that will confirm a broken crankshaft (as that piston won't be moving). It's much easier than removing the oil pan.

[splitsecondcb]

A broken crankshaft is VERY unlikely... however, if the timing belt isn't turning, it's possible.

Check compression on all cylinders. If nothing happens in a cylinder, that will confirm a broken crankshaft (as that piston won't be moving). It's much easier than removing the oil pan.

thanks i'm going have to buy a compressor tester then and if my crankshaft was broken would it read any compression?

[Tippey764]

thanks i'm going have to buy a compressor tester then and if my crankshaft was broken would it read any compression?

If your crank shaft was broken then only part of it would be spinning. So the pistons hooked up to the spinning part would give you compression but everything after the brake in the crank wouldnt give you compression because it isnt spinning.

[excoupemt5]

it could also be a broken keyway... No compression on one cylinder is likely if your timing belt isnt moving, weather or not the pistons are moving. IMO, the best way to check for a broken crank is put a socket on the crank pulley bolt and turn it. if the flexplate/torque converter spin when you do this, then your crank is in one piece. If the crank checks out okay, next step is pull the lower timing cover and determine why the timing belt isnt spinning...

Good luck, and fingers crossed that the crank is ok.

[quaidum]

you can also put a socket extension in the cylinder with the spark plugs removed turn the crank and see if it moves and check on all four

but even then if your crank is broken closer to the rear main seal but after the fourth rod journal then you would have to check at the flywheel/flexplate

[splitsecondcb]

okay i twist my crankshaft well the bolt under the car on the left side and the crankshaft twist also it twist the timing belt and the torque converter but when i start the car it spin the flex plate and torque converter the other way but its not twisting the timing belt nor the gear on the bottom and the timing belt is still perfect. my friend said the torque converter might not be in all the way because when i twist it by hand it'll grab, and when i try to start it the camshaft is not being grab because the torque converter is moving in cycle to fast. could that be the problem or the other reason is when i twist it by hand it twist the opposite way and its grabbing but when i start the car it spin in the opposite direction of doing it by hand and the torque converter is not grabbing the camshaft? sorry if i don't make sense because i am confuse. anyone can help me with this?

[deevergote]

I can't make sense of what you're saying...

[92smokeaccord]

maybe the b0tt0m c0gs l0ck br0ke 0r stripped 0ut and its n0t grbbing the crank.thats all i g0t f0r n0w.

[splitsecondcb]

sorry i didn't make sense i was tired last night, trying to get this done. well i know the camshaft is not broken but im thinking yes somewhere in there might be stripped. so i have to take out my tranny. and see if the car will start after i fix it.

[Superfly]

I don't know about autos and flexplates, but on manuals the starter actually spins the flywheel I believe. So it wouldn't be that unusual for the flywheel to spin while trying to start the car. So that wouldn't mean anything.

I bet your timing belt has sheared some teeth off of it. I hope you didn't bend any valves.


A broken crank would be the last thing that could be wrong in this scenario IMHO.

[Superfly]

Oh and...

If things spin the opposite direction when you start it with the key, YOU are spinning it the wrong direction by hand. Spin counter clockwise. See if the cams spin throughout the full motion. If they do not, it's your timing belt.

[ATS666]

If the crank is broken it would have destroyed the bock leaving you with some nice viewing windows in the block and pan.

Pull the valve cover and side cover and you will see the problem.

[wed3k]

sounds like your timing is off, if it sounds like it is free spinning then there is no compression aka, nothing holding the piston back.

here's what i know from what you typed.
-Crank is intact
-Flexplate is intact and connected
-Torque converter is bolted on
-Timing belt spins so it is intact but may not be timed

[splitsecondcb]

yes, so is that also why the car is free spinning and not cranking? because i had a mechanic come check it out and he said my transmission is messed up and i need a new one. if so im probably looking into getting a prelude tranny. so for now im trying to find out what year prelude and the best tranny from a prelude be good for a automatic cb. is there a way to see if my timing is off even tho my timing belt won't spin when i cant crank the car?