Easy way to check if timing belt is broke?

[blizake500]

If I'm going to buy and car with an m20 is there a simple way to check and see if the timing belt is broke? Certain cover I can take off or use a flash light to look under the cover? Thanks in advanced

[mbonder]

The engine won't run if the timing belt is broken, I'd say that's the easiest indicator.

The m20 is an interference engine, so if the belt breaks you are going to have piston to valve contact and you'll lose compression in the cylinders affected. Without taking the distributor cap and rotor off you can't pull the upper timing cover off the see the belt, so it's not really easy to get to.

[blizake500]

The engine won't run if the timing belt is broken, I'd say that's the easiest indicator.

The m20 is an interference engine, so if the belt breaks you are going to have piston to valve contact and you'll lose compression in the cylinders affected.

Right. I know that. Her engine doesn't run. She says it's been sitting for a while and the battery is dead. I'm afraid to try to start it because I don't want bad gas all in the gas lines. I just want to make sure the internals aren't ruined from a broken timing belt. An old lady is selling the car so I don't think she's going to let me take the car apart to see if belt is broken.

[noid]

Open oil cap, look inside, do you see the valve train moving when cranking? If no, then your timing belt is broken.

[uturn]

There's the timing belt inspection cover. It's next to the alternator, just know it's rubber and might crumble apart when you take it off.

[mr.vang]

Crank the motor by hand. There shouldn't be anything prevent it from turning. If it is, the piston is hitting the valve.

[digger]

pull the dizzy, turn crank with (22mm?) socket and see if rotor spins as crank rotates. its not the smartest idea to crank the engine if you think the belt is broken

[bangn]

Hand crank for sure and see if the rockers rock when you move the crank slightly..

OR put it in gear and rock the car back and forward if shes a manual

[roguetoaster]

If you don't want to crank it or turn it with a 22mm as it's hard to reach the crank bolt on M20s you can do the following while looking for cam movement at the oil filler hole. Lock steering wheel, hock front wheels in both directions, raise rear of car (put jack under the middle/front of the diff with a block of wood on the jack), place jack stands under the car, put car in gear, release parking brake, turn rear wheel by hand.

An easier version is the check position of the cam via oil filler hole, put car in gear and roll it forward or backwards as required and check end position of cam. You may wish to scribe a small mark on the cam to make this easier.

Be aware that you might damage a valve this way if the belt is broken.

[flyboyx]

If you have a broken timing belt, i cant think of a single instance where the head isnt already toast. There are some good ideas here, but dont worry about causing more damage because if its broke, its already fucked. If it were me, i would pull off the tappet cover. Look for broken rocker arms. You can also see the back of the cam gear and timing belt from here. See if the belt is loose. Next, id put a floor jack under the front subframe, jack up the front half of the car and get a box end wrench on the crank bolt from underneath.

[blizake500]

Open oil cap, look inside, do you see the valve train moving when cranking? If no, then your timing belt is broken.

So if nothing moves at all its broke?

[Kershaw]

Yes. The timing belt is what causes the top half of the motor to move. If it's snapped, nothing up there will move.

[uturn]

Removing part #8 will enable you to see the belt.
http://www.realoem.com/bmw/enUS/show...diagId=11_0405

[digger]

If you don't want to crank it or turn it with a 22mm as it's hard to reach the crank bolt on M20s you can do the following while looking for cam movement at the oil filler hole. Lock steering wheel, hock front wheels in both directions, raise rear of car (put jack under the middle/front of the diff with a block of wood on the jack), place jack stands under the car, put car in gear, release parking brake, turn rear wheel by hand.

An easier version is the check position of the cam via oil filler hole, put car in gear and roll it forward or backwards as required and check end position of cam. You may wish to scribe a small mark on the cam to make this easier.

Be aware that you might damage a valve this way if the belt is broken.

you take the clutch fan off (2 min) and youre there....

[James Crivellone]

Crank the motor by hand. There shouldn't be anything prevent it from turning. If it is, the piston is hitting the valve.

Not always, I've had motors come in that spin freely, with 5+ broken rockers and 6 - 8 bashed valves!