Timing Belt Blues

[pathhunter72]

OK, let me tell my story, then hopefully one of you great people can help me.

 

I was taking my boys to school one morning, dropped one at the middle school and took off to take the other to the HS. Going around the middle school, I headed south, coming up to a flashing red light behind an elementary school. OK, so I stopped, looked and took off, school zone is 10 MPH, then it just died. So I pulled to the side of the street and like I did the very first time this happened (another story), turned the key to try and start, then I snapped tht it was the timing belt. So had the boy push us to a side street. Had the Path towed to the house by a friend, started taking everything apart, but could not get the bolt off to the bottom sprocket/pulley. Had a local mechanic put it back together-with new belt, water pump and thermostat. He calls and tells me that there is no compression to #1 and #4 and unsure about #6 (he couldn't get to it). So I asked him if he turned the #1 piston to TDC and he tells me that "you don't need to do that". He also tells me that I probably have a or couple of bent rods.

I can understand if I was going down the highway at 75MPH, yes, engine would be trash and I would not be writing this, but 1000RPM's and comi g off a stop light????

I would just like to know, if it was to be placed at TDC and everything else counted and taken care of and without taking the valve covers off, would I have my engine back? I think he is just trying to get extra money out of me, but if I am wrong, I will eat my words.

 

Thanks to everyone and anyone that can help me.

[Kingman]

You wouldn't be bending the rods at that low of RPMs, you'd be bending the valves when they collide with the piston. That isn't hard do considering the inertia and forces inside of a working engine...

 

Even with a couple of bent valves the thing would still run, just like complete crap. I'd do the compression check yourself...

[ZombeeXXX]

I'd verify your valvetrain timing before you try to go much farther. If your mechanic didn't put it at #1 tdc to begin with, I'd be inclined to say he's a fool. I can't think of any other way you could be sure it goes back together properly.

And yes the valves generally take the brunt of the damage. Tops of pistons can be chewed up too.

[Precise1]

Oh My. Do not let that mechanic do any more work on the truck and dispute paying for what has been done as he is obviously incompetent!! The engine must be rotated to TDC on the #1 cylinder on the compression stroke and then the cams must be rotated to align with the marks on the rear timing cover. When the belt goes on and is tensioned, there must be 40 teeth between cam sprocket marks and 43 between the drivers side cam sproket mark and the one on the crank pully (numbers may be backwards). How the hell else would anyone know how things were sync'd??

 

There are several full write ups on this, one by a certified nissan mechanic for reference, but the first step is to get your truck away from that hack before he damages it even more.

 

Al low rpm you have a better chance of light damage, but it can still occur. If the valve train is way out of time, more damage can occur rotating the motor, but if it is too far out, it will hand up at some point.

 

Have the timing belt properly installed and then do a compression check, that is how I would proceed.

 

B

[pathhunter72]

I just want to thank all of you who took the time to analyze this little, but big situation, thank you so much!!

[Alkorahil]

X2 what Precise1 said!