25thhawk

iTrader: (3)

I never had a problem throwing serpentine belts before. I recently replaced the belt and I am having a problem with it walking on the pullies. Today it shredded the belt, so either way it is getting a new belt. I recently changed the rear gears to 4.30's and the car makes about 430rwhp. Am I at the point where I need a manual tensioner or is my stock one worn out? or did I just get a crap belt? Thanks

Ryan

LS6427

iTrader: (2)

The GM factory tensioner is a garbage design, especially when you mod your engine and make more power. Its not gonna stay on.

You need to get a Katech fixed tensioner. The belt will never come off again. Also, a tensioner that bounces (spring loaded) is what wears serpentine belts out....if they are fixed with zero bounce, they hardly wear out. My belt got thrown twice in one week after my 427ci went in. I got the Katech tensioner and a new serpentine belt.......I've never thrown the belt since I installed the Katech tensioner, and this belt I have right now is the one I installed with it....back in 2002. My belt looks brand new still.

.

25thhawk

iTrader: (3)

Thanks. How often do you check/ adjust the manual tensioner? What kind of belt are you using, 9 years is pretty good belt life.

jam01

how is the factory garbage? mine is working fine, granted it is still stock which is what the tensioner was designed for. why is it always gm junk with you, you push the limits of the design and sure things will break wear out faster. just tell the guy to buy the katech or what ever else is being asked.
and no im not starting crap, im just asking for reasonable answers.

and i second the katech, and as far as the tension i would think it comes with specs?

racingcameron66

Katech all day.

wssix99

iTrader: (5)

Bottom line - If your belt was fine with the extra power and then the problem only came up when you replaced the belt - its not the tensioner. The belt was either wrong or routed incorrectly.

BTW - There are good attributes of the stock pulley design in that it self-adjusts to belt stretch. In a 100K mile-before-tune-up stock engine, this is a good and necessary thing. If you want a set-it-and-forget-it pulley, stock is the way to go. If you do more maintenance on the car, don't mind checking the belt slack, and are racing, an old-school tensioner may be good.

25thhawk

iTrader: (3)

Thanks. I'm really not sure that I need or want the manual tensioner. The stock tensioner never had an issue until I added the rear with the 4.30 gears. The motor revs much quicker now and I know that is the cause of the problem. I think I am going to get one of the pullies with the higher shoulders and a new belt first and see if that cures it. If not then I quess it is time for the katech tensioner.

wssix99

iTrader: (5)

What kind of belt/part number did you install? Also, did you double check the belt routing against the sticker on the driver's side shock tower? (You can route the belt different ways, but only one way will keep the belt on.)

Also, did you check the tensioner marks? On the tensioner body, there are three raised marks. On the pulley (the part that moves) there is one.

The two raised marks on the body, which are closest together on the right are the minimum and maximum lines. (The one further all the way over to the left doesn't mean anything.) The mark on the pulley should be on or between the minimum and maximum mark. If it isn't, the belt does not have the correct tension.

LS6427

iTrader: (2)

Exactly, your stock, it should work fine. But you will change more belts over time than I will.

I say junk because its a shitty design, they could have made a fixed tensioner and it would have been cheaper for them to design and produce.....and they wouldn't have handed all of us ANOTHER problem when we mod our cars....and GM KNOWS that thousands and thousands of people WILL be modding their cars and upping the power. The belts get thrown off because of higher power and faster revving engines. My belt never went anywhere the first 4 years it was stock....the week I had my 427ci in, the belt was tossed off twice. So that is the reason belts get thrown off. The engineers at GM have made a ton of shitty decisions on our cars and many more GM models. Thats why American made cars are crap compared to most foreign cars. It just pisses me off.........

.

LS6427

iTrader: (2)

This is why its really NOT a good design. The bouncing causes the belt to stretch. Like I said earlier.....my serpentine belt on my engine today is from 2002. The Katech tensioner is set in the same exact position its always been in. Fixed tensioner = (almost) zero belt stretch. I'm assuming the belt is still stretching because of heat cycles over time...but its just as tight as when it was put on in 2002 and again, tensioner is still in the same exact position. So really, fixed tensioner = zero belt stretch.....at least over a 9 yr period.

The belt is starting to show those little cracks on the edges....but thats just material breakdown.........I have one with me all the time in my car in case it lets go.



.

25thhawk

iTrader: (3)

Cant really say that I check the marks on the tensioner. I never had a problem prior to this so I really wasnt paying much attention. It was a Dayco (autozone) belt. So that could be a problem in itself. I put the larger pulley on today. Waiting on my turn one PS pump to see how it all works.

The reason i went the route of the shouldered pulley is only because it was cheap and easily available. I have no doubt that the katech tensioner is a better piece. Is it necessary? I cant say. But if this doesn't work, I guess I will find out.

Ill post results as soon as I get it back together. Thanks

Ryan

LS6427

iTrader: (2)

My belt thats been on my engine for 9 years is a Dayco.

The shouldered pulley should keep the belt on...but remember each time the belt wants to walk off or get thrown, its going to be rubbing the hell out of the belt each time. So it might get worn prematurely and weakened. You'll know soon enough.

Used be this shouldered pulley called the Larry pulley. It was just a higher wall like the shoulder idea. But I haven't see them sold anywhere for a long time.

.

jam01

huh? first off gm has to produce a car that lasts if you mod your car to were it starts breaking things that is your fault. and many more people dont mod there cars, so who do you build it for the few or the many and the cost. if you really feel American cars are crap, than why did you buy it? and if you think you throw a little hp at any jap or korean or wherever that junk is made they wont break. if you abuse any make of car without any kind of common sense, knowing something will break and not fixing it before hand. who is to blame?

LS6427

iTrader: (2)

You missed the most important part of my post......GM could have designed and produced a CHEAPER fixed tensioner for our cars. They don't do that because they WANT our factory junk parts to wear out so we have to buy new ones. Thats a fact. Look at the complete crappy factory power steering fluid cooler they designed. They could have purchased off-the-shelf, already made coolers and installed them on every car....instead they design one that they know damn well will leak in as little as 1 year for some people. JUNK and cost GM a **** load more money to design and produce. So again...GM engineers designed a piece of crap part. But again.....they might be genius's because of all the poor saps that get GM replacement tensioners and power steering fluid coolers, along with many other over-priced and poorly designed GM parts.

Why did I buy an American made car.....ONLY because I liked the way it looks. I buy cars for their looks....anything can be upgraded. Look at my sig, it was all done at one time....I made a sub-par quality car into a very good quality car...all in one quick project. Now I am looking into buying a Mercedes AMG E63...thats got looks and top quality, but that car is expected to run perfectly and treat me good for years and years.

.

wssix99

iTrader: (5)

Come on now. Have you ever owned a 1980's or early 1990's car? Spring loaded tensioners were born for cars that can go 100K miles between tune-ups. (These cars have that "feature.") A fixed tensioner can never go 100K miles without needing adjustment. These cars were not designed for enthusiasts. They were designed for daily drivers who never take care of the car. Not enough of these non-enthusiasts bought them, so the cars (and the factory that made them) were/was killed. If the car was designed for high power modification and constant tuning, we would have to pay double the amount at the dealer. (I'd rather add a $2000 of performance parts (including a fixed tensioner - if needed) when modding my car than pay an extra $35K up front at the dealer.

GM knew of this very early. When my first one went in 2000, the dealer called engineering and they knew exactly what was up. By then, the car was on its death bed and changes not motivated by other models just didn't happen. I like the fix for this, though. Its much better than anything that would have been crammed in at the factory.

I looked at this also, but... no manual transmissions. I even looked at importing from another country but the dollar is too weak. The real nice thing about nostalgic American cars is that we can get parts! Finding stuff for a 10 year old German car is hell. (My brother and sister both have 10 year old BMW's and I laugh at them every time they buy a $50 air filter!)

LS6427

iTrader: (2)

Then maybe its just safe to say, GM engineers either design things that they don't want to last forever, which seems like a good plan as far as making money for GM, via future repairs. OR....GM engineers have made a ton of very stupid design decisions, and I mean allot of them. Which means they aren't all that good. I just have a tendency to point out those terrible designs.

My Katech tensioner has been in the same exact place since I put it on, with a new Dayco belt, from back in 2002. Its been on and off many times for other rerpairs and work on the engine.......but it never ever gets adjusted. Set it and forget it.

I'm pretty sure I'm going to get a 2008 E63 AMG....it'll still have the CPO warranty. I'm gonna wait another few months though. I would never get one without a remaining factory warranty or older than 4 years.

.

jam01

back in the 60's gm had a problem with belts throwing due too to much hp, so the made the groove deeper for the v-belt . i looked to see if this was a common problem with our cars and nope the design is fine. there are books on modifying ls engines and they recommend when pushing the design and hp on these engines to use the katech. i do know that rubber builds up on the pulley's and after time all pulleys wear out no matter who manufactured them. so maybe you could try cleaning up the grooves on your pulley and re greasing it.

wssix99

iTrader: (5)

This is exactly what is done - the "value engineering" method its taught to first year engineering students.

I don't know the exact numbers that GM uses, but they start design the car with an assumed design life. Back in the 80's, I recall that GM designed for 100K miles and the Japanese were much higher. I also understand that GM upped their design life in response to this. The big wild card is time... 100K miles over 5 years is very different than 100K miles over 15 years. So, as our cars get older, the durability will drop because the rubber seals and some lubricants can degrade with age.


Back to the topic - jam01's point is good. The more HP you are producing, the greater probability that the groves won't hold the belt on. However, I wouldn't think RPM's would be an issue unless you increased the redline of the car.

LS6427

iTrader: (2)

Then I should stop calling the GM engineers stupid....just dirtbags.....lol

Reason I was given by Katech as to why belts fly off using factory tensioners:
When I got my 427ci put in, then drove it under 4,000rpm for 200 miles like my builder recommended. A week or so later (because I did drive it 210 miles back from Orlando to Lauderdale) after it was broken-in....and I finally went WOT.....the belt flew off the first time. I put it back on and figured it was just a freak thing. A couple days later it happened again when I wacked the throttle. I called my builder (ARE), then I called the shop that installed everything you see in my sig (Norris Motorsports) and told them about it. They said to call Katech. Katech, who designs things for the Corvette C5R C6R and other road race cars......including the Katech fixed tensioner which was designed specifically because their C5R race car was throwing belts way back 10+ years ago.......said the reason the belt comes off is because of a modded/built engine that REVS faster AND has the power to back up those faster REVS. They said the factory tensioner can only BOUNCE up and down so fast, and it cannot keep up with an engine that can REV fast with power. So I bought it and the belt has never come off again, actually it simply can't with a fixed tensioner. The bouncing type tensioners also stretch the belts. So it a win win, even for a bone stock engine because a belt will literally last beyond 10 years. My belt is at 9 years right now.

.

wssix99

iTrader: (5)

No, call the accountants they work for dirtbags. The engineers go home, buy the cars they design, and then put good aftermarket parts on them.