OK...this is not a Porsche but I know there are a lot of smart dudes on this forum so I'm hoping you all can help me out.

My girlfriend owns a 98 Chevy Cavalier 2.4L DOHC

She went to start the car in the morning and the car would not turn over.

Eventually I found out that the timing chain tensioner broke apart causing a lot of slack in the timing chain.

So I bought a new chain, tensioner etc.

I noticed one of the cams is off timing about 1/4 turn...so I'm assuming the car jumped timing due to all the slack in the chain.

So here is my question:

With the timing chain removed and both cams timed up properly...should the crank turn a full revolution or not? Or does the timing chain need to be on the car?

As it is now, I can not turn the crank more than 1/4 turn until it stops, seems like something is binding up...or maybe this is normal because the chain isn't installed?...or does this mean she has a bent valve?

This is an interference motor.

Any help...I and my gf would appreciate it!

 

dude the words "interference motor" means that the pistons will hit the valves if the motor is turned over with out the cams moving in unison. You may have bent valves already in that head.. I would loosen the bearing caps on the cams to let all the valves close, pull the spark plugs and send compressed air to the cylinder with a compression tester hooked up to a air compressor. Listen to see if you hear any air leaking into the intake or exhaust. If so bent valve(s). If not then put the crank at TDC and get the cams set close to there marks, re tighten the cam bearing caps and then time the cams..

 

Thanks man. When I talk about the crank not turning more then half way...I mean when I put a ratchet on it and turn it over by hand. You think that would bend a valve? I did not try starting it like this.

I haven't even tried hooking everything back up together with the new tensioner to see if it will turn over yet.

So...as of right now the car is sitting:

- with no timing chain
- cams timed up with marks on head
- I turn the crank by hand and this is when it is stopped half way or so

I'll do as you described this weekend.

Thanks again.

 

It is hard to say as the valves do not run parallel to the bore of the piston, meaning that the angle that the valve is in relation to the piston is more like you are hitting the valve on it's side. plus a four valve head uses really skinny stems..

 

OK...I'll check it out. Thanks again. Happy new year.

 

how did you make out?

 

lol...almost all of the valves were broken into 2-3 pieces...my friend bought the car and put a new head in it...runs ok now.

Thanks for the help.