Speedy Auto > Auto FAQ > Cars > BMW

BMW: Timing belt help 84 bmw 258e, crank shaft, timing belt


Question
I had my timing belt break clean with about 150,000 miles. I took apart the complete front end of the engine to get to all the gears. I marked the specific areas Chillton told me to. I replaced the distributor cap, and belts while doing this. I finally got the belt on and when I went to start it the car made a seize sound. The crankshaft is still moving and I set the timing to the first plug by eye.
Is there an easier way to do this? I still can not get it started.
Hope I explained this well.


Answer
Scott,
 If the timing belt broke while you were driving the car, then chances are that all/some of your valves are bent.  The timing belt keeps the camshaft in "time" with the crank shaft.  This also keeps the valves from being down while the piston is coming upwards.  When the belt broke the camshaft stopped in it's place leaving some of the valves in the open/down positon.  The momentum of the vehicle and the reciprocating assembly keep the pistons moving momentarily.  This allows the pistons to make contact with the valves.... and subsequently bends them.  You need to check all of your valves out before continuing.  You are probably wasting your time doing other things.

 For reference a timing belt is only supposed to last around 100,000 miles, so I'm surpised you made it as long as you did.  Another thing, if you haven't changed the water pump... now is the time.  It too needs replacement at 100,000 miles.  So save yourself a large headache and do it now.  
 Good luck,
 Josh