So last night I had a mechanic put on a timing belt for me as a side job. Now this guy is a mechanic during the day and claims he worked on thousands of Maximas. So he put it on and changed all the belts. I drive home and its OK. Going to work, after about 10 miles the car starts bucking not bad at first, then real bad. Immediatly I pulled over on the LIE and shut it off. Thanks to all the info on these threads I figured its the timing belt and driving for any amount of time could crush the valves. So I had it towed to my daytime mechanic (firestone shop) and he said the timing belt slipped off and he has no idea why or how. He said the valves seem fine. So now he's finishing it up and changing the injectors for me (unrelated). Luckily for all the talk of zero clearance that I read I was able to save the engine. How the hell does a timing belt slip off? and I even changed the tensioner.

 

Same way your belt would fall off your pants: You got the wrong size or it wasn't put on right. Seriously, I've only heard of a timing belt "walk off" a couple of times with new parts(belt and tensioner). It's rare. The two times I know of were from the wrong belt. They were close enough to be snug, but still off a few mm. But who knows? I'd say only the people who work on your car could tell you for sure.

 

Seemed to be the same exact belt, but who knows. Actually the old belt was looser than the new one, I was told they stretch in ti,e. I trust Internetautomart should know the correct part.

 

the belt definitely does stretch with time, my only theory is that when it was put on he didn't quite engage the belt fully on one of the pulleys.
but that's only a theory.

 

Yeah that's what I think as well, needless to say I will not be using this mechanic anymore!

 

That would require mastery in itself.

Maybe the belt was warped: if its inner threads are shorter (mfg problem) then it would self propel out. Send the belt back and demand check, refund for all work, tow.

Maximas use both rounded and square teeth: only square teeth belt for square sprockets. Stealeship t here is in the mastery class: they managed to swap round belt on my squared sprockets at 60k. Noisy.

So stealership workmanship is only quarentee for 400% price hike...

 

Well I got back the car and spoke to the mechanic. He said it didnt slip off (I miss understood him) but it was put on incorrectly. It was one tooth off and he said as you drive the timing gets more and more messed up until you could feel its bad. He said its a good thing I stopped when I did. he repositioned it and I successfully drove my 30 miles to work today

 

I am afraid the ppl on this thread are talking about different things. If the engine starts 'bucking', than it is the belt jumping the teeth, not slipping off completely, right? Basically change in timing on one or both sides of the V. The belt coming off the camshaft gears = stopped camshaft + going pistons = bent valve stems. Hoping I am making sense.

Edit:
I posted that before I saw the last posting. Makes sense now. Still may be the wrong type of belt, i.e. round teeth where square teeth required or vice versa or just a completely different belt, which looks same by coincidense.

 

I asked him about that and he said it seems to be the right belt, just that the cam shaft was off timing by one tooth. Well hopefully that solves this dillema.

 

One of the cams being off by one tooth does not make anoticeable difference in performance, I can bet my boots on that. But if it is progressing - than yes, you run into the problems. The only way the problem may be progressing is if the belt is not designed for the engine. I know for sure there are many belts out there that have equal number of teeth and equal size, but still they are different. May be the case, or it may be just one off low quality belt. What does it cost? I would have replaced it anyway when the whole engine is at the stake.

 

It is cheap enough, but the cost of labor on that job is high. So far no problems, so I'll see how it goes.

 

he also didn't buy a low quality belt, he got a Gates brand belt.

 

Brand name does not guarantee anything, specially in weird situation like that.

 

even OE nissan doesn't guarantee that the part is right in the box

 

"I could take a dump in a box and gurantee it if you want...hey I've got spare time"

Tommy Boy quote