shredded belt response

From: "WANDA FOX" To: "Shep" Subject: Re: cam belt shredded?? Date: Sunday, June 03, 2007 6:49 AM

okjay upon pulling the front shield off exposing the pully's and tensiorer,here's what i found-as i told you or failed to report thew first time i changed the belt(10 months ago)i did not change the tensioner or the idler pullys,just the belt,the belt this time appeared to be pulling forward and shredded,with the help of a very good mechanic neighbor we noticed the idler pullys and tensioner were extremely shiny and the edge was thinner to the outside(inside lip of pullys was hardley touched)suggestion that that belt for some time was riding at an angle towards the front before it probally finelly jumped and shredded,even though the pullys and tensioner seemed to be sturdy and no wear or play in the bearings(they were rotating quite freely and quite)there seemed to be a crown in the surface where the belt would ride,suggesting wear,the flat surface not true and square but angles even the slightest at an angle would indeed cause the belt to ride uneven and cause what happened(am i on the right track here??)the cranks turned as they should do upon cranking and the cogs are tight and turn as they should upon checking,taking a straight edge to the alignment of the cogs,i checked there trueness to each other as to the trueness to there alignment to the crank,everything was in line.so am i right in thinking the idler pullys and tensioner where worn and the cause? thanks bob

----- Original Message ----- From: "Shep" Newsgroups: alt.autos.pontiac Sent: Friday, June 01, 2007 3:47 PM Subject: Re: cam belt shredded??

You need to pull this apart of course and look at the tensioner and idler > pulleys and bearings. > > some opinions please from the more mechanic wise!,94 grand prix > > (3.4)dohc,last summer my car lost power and then died,just cranking ,no > > start,then i discovered the timing cam belt had worn and the bottom engine > > crank was just turning,the cam belt had no teeth ribs left to catch the > > crank ribs,the belt was just sitting there while the crank turned.,i > > changed > > the belt with the help of a mechanic and the car ran just great,power and > > strength till today,now it's been about 10 months since i changed the belt > > and today the car lost power and ran about 10 miles or so with the loss of > > power till the car stalled and backfired,won't start now,raising the hood > > i > > right away noticed the cam belt inspection covers were cut into and the > > plastic hot and melted,upon removing them further the belt was completly > > shredded and some strands still hanging on to the cams on the left side of > > cams,the right set didn't even have the belt on them anymore,there were > > belt > > shavings all over and just a few stands just left ,now if the car still > > ran for some miles after the belt started coming apart till it > > disenagrated > > it tells me that the cranks and cams were moving (not locked)i have since > > then turned the cams so they are free),so why did the belt(only 10 months > > old)shredd so quickly,could it be a bad or wrong belt??could the tensioner > > have gone bad or have an effect?? what would be the most possible > > reason??,,is there a certain type belt that should have been used,are they > > all the same ?? thanks. bob > > > > > > > > > >
Reply to
robert -wanda fox
Loading thread data ...

Maybe. Could the belt have been off a tooth or two? I shredded a belt once due to being off one tooth.

Reply to
PauL

That doesn't make any sense. You just shredded a belt that was off a tooth. There's no cause and effect there.

Reply to
Joe

One tooth off on the balancer towards the engine. There was enough warpage being over the balancer lip to rip it apart - took a year. I could see the evidence by the rust vs. no rust on the balancer.

Reply to
PauL

this is a little foggy the way you describe it but if i understand you correctly,it sounds like the cam belt was riding inward towards the engine and started to shred once it was hitting the block(right?),,my belt was doing the opposite,riding outward on the cams till it was riding on the idler pully lips(the outside of the lips were shiny and thinner then the inside lips of the pully and tensioner,which the inside lips were thicker and not worn,),,this explaned to my was a worn pully and tensioner problem,not a missed tooth problem,the inside track that the belt rides on which was crowned and worn to a slight angle is what caused the belt to move one way or the other,even though the belt rides in grooved teeth on the cogs and crank,the pullys wornness still made it come forward to fail,any comments or opinions please??

Reply to
robert -wanda fox

MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.