Car Forum / Honda Cars / April 2006
Do Timing Belts Ever Stretch?
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duckbill - 08 Apr 2006 05:06 GMT I have been an auto hobbiest for qiute a while and wondered what this Forum's best and brightest think about the following: I noticed a very simple proceedure to adjust timing belt tension in my factory maint book on my 95 Civic by removing a plug on the lower timing cover to get at the adjusting bolt and removing the top timing cover to check for loosness. This prooceedure would be quick and should be a piece of cake to perform. This makes me wonder if it might be a good idea to check belt tension at 45,000 miles and adjust if needed? Do these belts ever stretch or not? Of course I mentioned my 95 Civic EX timing belt having excessive looseness (over 1.5" in 78,000 miles) in a previous post and had several good responses. I have seen an 85 Nissan 300Zx (mine) have a loose timing belt at 70,000 original miles way back when..... Some manufactures use an active hyrdraulic tensioner(Mazda V6 89-98 for example) versus a lock down system like Honda uses. I have not seen this issue addressed anywhere, but think this discussion could be of benefit to the entire Honda community because our engines have such a long timing belt change interval and are of interference design. So,I'm still wondering? Thanks in advance for your thoughts and recommendations.
Ron Jones - 08 Apr 2006 17:36 GMT I've some knowledge of this type of belt on industrial equipment. These are not like fan-belts. Typically they have Kevlar cords and extremely little tolerance for stretch - less than a metal chain. That is they maintain their length right up to the point of catastrophic failure. So I don't think this sort of inspection would be much help.
rj
>I have been an auto hobbiest for qiute a while and wondered what this > Forum's best and brightest think about the following: I noticed a very [quoted text clipped - 15 lines] > of interference design. So,I'm still wondering? Thanks in advance for > your thoughts and recommendations. Bucky - 09 Apr 2006 07:38 GMT > Do these belts ever stretch or not? > I mentioned my 95 Civic EX timing belt having excessive looseness > (over 1.5" in 78,000 miles) in a previous post and had several good > responses. I have seen an 85 Nissan 300Zx (mine) have a loose timing belt > at 70,000 original miles way back when Yes, timing belts stretch. But I'm not sure I understand your question, because you already stated that you had past experiences with loose timing belts, so doesn't that already answer the question?
duckbill - 09 Apr 2006 16:47 GMT Thanks for the input Ron. And Bucky, you have made a good point. But to answer that point....I have to say the following: I did not install either of those timing belts, so I'm not sure they were installed properly. I have read sooo many posts on Google on "stretched timing belts" that I'm convinced there is about a 50 - 50 split on the issue. I would say that timing belts are not supposed to stretch, but some do......for whatever reason. The timing belt and its tensioner is operating in an oven type enviroment, and might be starting out the day at the same temperature as cold your freezer..........I'm very glad I opened up my timing belt cover on my 95 Civic EX with 192,000 miles (78,000 on the belt, seals and water pump) after hearing an unusal but not loud noise. First, I found a very loose timing belt with over 1.5" of deflection and second, the tensioner was in very bad shape with no grease left in the bearing. Cheers.
Bucky - 09 Apr 2006 22:59 GMT > answer that point....I have to say the following: I did not install > either of those timing belts, so I'm not sure they were installed > properly. Oh I see, so what you're saying is that you discovered you had loose belts, but you were not sure if the belts got loose because they stretched, or if they were loose when they were installed.
Well, I had a friend who had an old Honda Accord with about 80,000 miles. One day (while I was riding with him), the engine died. After he had it towed to his mechanic, the mechanic told him that the timing belt (original factory) was stretched and loose, so it needed to be replaced. To me, that's proof that timing belts stretch. How else could you explain that scenario?
duckbill - 10 Apr 2006 03:44 GMT Bucky, you make a very good point. You're on the side of the fence that says: timing belts stretch. And then there is Honda that allows us to drive their newer cars to 105,000 miles on a timing belt while other manufactures are changing them at 60,000 miles. I agree with you to a point. So, I'm straddling the fence by saying: some timing belts stretch. Ron, on the other hand, works with this type of belt and says they don't. I wonder what would cause timing belts to stretch when the're not supposed to?
jim beam - 10 Apr 2006 03:17 GMT > I have been an auto hobbiest for qiute a while and wondered what this > Forum's best and brightest think about the following: I noticed a very [quoted text clipped - 4 lines] > This makes me wonder if it might be a good idea to check belt tension at > 45,000 miles and adjust if needed? Do these belts ever stretch or not? no.
> Of > course I mentioned my 95 Civic EX timing belt having excessive looseness [quoted text clipped - 7 lines] > of interference design. So,I'm still wondering? Thanks in advance for > your thoughts and recommendations. there's minimal wear, which can cause slight looseness, but the belts don't stretch - as stated by ron jones, their length is the same throughout their life. if you have one that's loose, it wasn't set right - an apparently common problem since it's spring tensioned, not manually tensioned. if the factory tension procedure is not followed to the letter, you'll have problems.
on a side note, ability to retain tension and lack of stretch are a couple of the reasons why belts are superior to chains in this application.
duckbill - 10 Apr 2006 13:25 GMT Thanks for weighing in again on the issue Jim, I know which side of the fence you're on. I'm straddeling it. I set my tension by the book and am getting about .25" of belt deflection versus over 1.5" deflection of the old belt on my 95 Civic EX. The previous job was done by the dealer 7 years and 78,000 miles ago. How could a dealer screw up something as simple as a timing belt? Anyone else out there have a loose timing belt when doing their car's first belt change or the first belt change after a Honda Dealer replaced the belt like me.
jim beam - 10 Apr 2006 14:34 GMT > Thanks for weighing in again on the issue Jim, I know which side of the > fence you're on. I'm straddeling it. fine, but check the data on belt materials. do tires "stretch"? the same aramid fibers.
> I set my tension by the book and am > getting about .25" of belt deflection versus over 1.5" deflection of the > old belt on my 95 Civic EX. good.
> The previous job was done by the dealer 7 > years and 78,000 miles ago. How could a dealer screw up something as > simple as a timing belt? easily. i've repaired many vehicles screwed up by dealers. you wouldn't believe. a friend came to me the other day because his car was making a "strange transmission noise". the dealer wanted to change the transmission for thousands of dollars. it was simply a broken motor mount.
> Anyone else out there have a loose timing belt > when doing their car's first belt change or the first belt change after a > Honda Dealer replaced the belt like me. yes. me.
bottom line, dealer mechanics should know the most because they specialize and work on the same vehicles again and again. but fact is, some individuals are not good with their hands and/or didn't pay much attention in class. so they're not good at their job. statistically, the dealer gives you a good chance of the job being done right, but it's absolutely /no/ guarantee.
duckbill - 10 Apr 2006 18:57 GMT Thanks again Jim. There are very few guarantees. A friend of mine and I asked a tire dealer to change both passanger side tires on her van and made it very clear we wanted to keep the passanger rear tire as a spare The driver's front was brand new with less than 2,000 miles on it. The passanger front was well worn had the belt breaking loose which was visible. The Dealership proceeded to change both rear tires , one of which had less than 10,000 miles on it and kept the better of the two back tires!........... If you find a good mechanic, tip him or her and send him more business. If he makes a mistake, work with him and you will be rewarded 10 fold. Just my opinion of course.
Bucky - 10 Apr 2006 18:59 GMT > easily. i've repaired many vehicles screwed up by dealers. you > wouldn't believe. So Jim what you're saying is that if a belt is loose, the only explanation is that it was equally loose when it was installed. In other words, if a belt deflection is at 1.5" after 80,000 miles, it must have been around 1.5" out of the factory.
What if the following situation occurred: You get a new car out of the factory. You check the tension, it's at 1.25" deflection. 80,000 miles later, you recheck the tension, and it's at 1.5" deflection. Would that prove that timing belts stretch?
Like I wrote in another post, my friend's car died after 80,000 miles. Mechanic checked it out, said it was a loose timing belt and replaced it (he still had the original factory timing belt). It obviously was not as loose during the first 80,000 miles, otherwise the car wouldn't have started. So how do you explain that?
jim beam - 11 Apr 2006 04:04 GMT >>easily. i've repaired many vehicles screwed up by dealers. you >>wouldn't believe. [quoted text clipped - 3 lines] > other words, if a belt deflection is at 1.5" after 80,000 miles, it > must have been around 1.5" out of the factory. pretty much, yes. as i stated before, you do get a small amount of wear, but that's not stretch.
> What if the following situation occurred: You get a new car out of the > factory. You check the tension, it's at 1.25" deflection. 80,000 miles > later, you recheck the tension, and it's at 1.5" deflection. Would that > prove that timing belts stretch? no. see above.
> Like I wrote in another post, my friend's car died after 80,000 miles. > Mechanic checked it out, said it was a loose timing belt and replaced > it (he still had the original factory timing belt). It obviously was > not as loose during the first 80,000 miles, otherwise the car wouldn't > have started. So how do you explain that? car wouldn't have started??? would this mechanic also say the blinker fluid level effects starting too? your friend needs a new mechanic if they tell b.s. stories like that. if the belt has not jumped, the cam timing remains and the car therefore will start. even if it's jumped a tooth, it'll still start. performance will suck, but it'll start. if the timing is any further off, there will probably be interference and therefore severe damage. looks like your friend got hosed for a premature belt change to me.
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