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. Car drove fine the night before and when she turned it off in the same spot in the driveway the night before.

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 took the timing chain side cover off and 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:

At this point I have the old chain removed.

I've timed up the cams properly...

and I put a ratchet on the crank to see if the crank will turn a full revolution...should the crank turn a full revolution with both cams timed up properly or not? Or does the timing chain need to be on the car for all of the parts to move together?

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?

My friend is telling me that there is no point in installing the new chain and tensioner since the crank will not turn a full revolution (w/ chain off). He says she's got a bent a valve?

What do you think??


I know I'm new here but any help I can get on this I and my gf would GRATELY appreciate it!

 

anyone? I've heard from a few more people that it's a bend valve so I guess I'll move forward with that...

 

I don't know much about Cavaliers but usually engines like these are interference engines so if you jump timing you've bent some valves.
And no the cams will not turn with the crank if the belt is not on. Also, that rough spot you're hitting on the crank is more than likely just the compression stroke of the engine. But like I said you probably bent the valves since most newer engines in fwd's are interference.

 

I had some problems with my 2.2 Cavalier cylinder head and got a head from King Cylinder Heads and everything was GREAT. http://kingcylinderheads.com/ I believe they carry the DOHC heads also. They were also very helpful with questions I had about the problems I was having. Of course if the damage isn't to bad you might be able to just replace a valve or 2 instead of the whole head. Good Luck!

 

Crankshaft should definitely not turn full revolution without chain. Timing marks are only for installing the chain, when you turn the crank they become meaningless.
With chain properly installed you could remove spark plugs and see if engine turns freely 2 revolutions.
If it does you could measure compression in cylinders, a cylinder with bent valve will show significantly less pressure.