I like blue, so I use Gates

 

Besides the belt, nothing else really is due for replacement at 30-40k though, right? The water pump and rollers aren't as recurrent as the belt. Has anyone had a real world failure with the blue belt before the interval? I've read many accounts of that happening with the OE belt, although it's probably due to incorrect tension or other parts failing more-so than actual belt failure if I had to guess. I'm building a non-interference engine right now, and have been eyeing the blue belt for months...maybe we need a test. I think nihil makes a good point.

 

Belt tech has come a long, long way since 1983. To say just use the oem rubber vice a kevlar reinforced is silly. Put the strongest belt you can in there.

 

+1

 

You're describing a "mechanical fuse" of sorts, and I totally get why some parts are designed to fail before others, but what I seem to be missing here is what horrendous outcome a failed belt would save you from that would have a worse outcome than a failed belt. What are these underlying issues you mention? I'm not intimately familiar with these engines and genuinely wish to learn the ins and outs, their quirks, etc...

I would assume they have, but by previously mentioned logic, there's no point if they did?

If that's the only associated maintenance item at that interval, running a longer lasting belt makes even more sense. I know in the land of recent'ish (mid 90's and up) Audi, the Gates blue is rated for at least as long as the factory belt, which itself has a recommended change interval in the 60k-80k range. Applications differ I know, but it should be indicative of the longevity of more modern belts as opposed to those available when the 30k interval was decided upon.

I'd be curious to know the causes of failure, along with the sources for the failed belts. Cheap Chinese labeled "OEM" vs. reputable Porsche approved supplier, etc...

 

Ummm. If there was no point why not just use a piece of string? So that is not my logic and never will be. There is benefit from stronger material, but this benefit is not limitless. Additinally, it's useful to recognize that modern rubber tech can stand up to more oil, water, temp fluctuations, etc. It's been almost 35 years of innovation.

For the purposes of using a kevlar belt (that's what it is, right?), you would see your biggest benefit if you were to risk extending the accepted service interval. I'm not suggesting you do it. However, the 3 yr/30k miles rule is already extremely conservative and does not allow any margin for added safety through use of a kevlar belt.

Do you need a crane in the morning to lift your coffee cup? No. I do agree with you and others that testing would be nice, and stronger is probably better, but if there is no consequential difference than there is no difference. By one theory kevlar is better, but we need to know if there really is any perceived benefit. By another theory it is not beneficial.

And to brainstorm some underlying issues, how about oil leak, water leak, missing timing belt covers, improper belt track, bad water pump bearing or pulley, etc.

 

So, OEM/original formula somehow equates to using a piece of string? I was simply implying that if the originals were "good enough", then improving them would be a fruitless pursuit.

Fair enough, but it's safe to say no more extensive damage would be done by using a "better" belt in the event of some other failure?

Of course not, but the **** I take before that cup of coffee however...

Would the impact of any of these issues be mitigated by the presence of a weaker belt? If so, how? I've only taken a quick look at the internals by way of the mighty images.google, and I'm not seeing any obvious benefit to a mechanical fuse in that location.

So far the only solid argument (barring potential and arguable extension of maintenance interval) has been cost, which in my opinion is a negligible amount for a stronger part. If there is more to the situation I'd love to know, but if that's the extent of it, I'm ok with blowing the extra coin for a familiar and reputable product.

 

In what way is it stronger? I did not assume the OE belt was weaker in those specific scenarios which I mentioned. I think the belts probably each use glass cords to increase tensile strength, for example. What if Kevlar is not better for our application? Maybe the biggest risk is changing materials on such an integral part of a 30 yr old system requiring rather tight tension. How do we know if it has not been thoroughly tested? Maybe you have done the research and can summarize. I know through reading countless posts on the belt that the unknown is perhaps the scariest thing about it, speaking about what keeps you up at night (queue next joke).

 

According to ECS: "up to three times the heat resistance and tooth strength of a standard belt"

Given this, I have not done any testing of my own to substantiate that claim.

In a belt, unless there is a desired and engineered failure point to protect other components, stronger is better. The less it stretches, the more it's going to retain that desired tension. While the Gates blue specifically for the 944 may or may not have been tested for this application (no idea if it has or not), I do know that they have seen quite a bit of use on other makes, including one of my own Audis (not yet hit change interval since installation), another local Audi I did which was my first hands-on experience with the Gates blue (no idea how far that one has gone since install), and dedicated track cars that see quite a bit of abuse.

I'm comfortable enough with the belts themselves to feel that they are a well engineered product. My only question is whether or not there is a specifically intended OEM failure point that a stronger belt would compromise, which would give credence to the previous claims of "OEM is better/fine". So far I have seen zero evidence for that.

Regarding being an unknown, it's just a belt. Belts are one of the oldest and most simple means of conveying motion from one rotating assembly to another. The only even semi-unknown is that magical mystery desirable failure point, and I have yet to hear at any point in my life "gee, I wish my timing belt had blown because it would have prevented damage from....".

As for what keeps me up at night. Life long insomnia and a 9mo old. Sleep is a thing of the past.

 

FWIW, I talked to Steve over at 944online about why they dropped the blue belt. He said the mfg suggest the same maintenance schedule with them as the OEM. 3/30, so they dropped them, without extending the maintenance window, most people wouldn't spring for it, so it didn't sell. So, it got dropped.

It's designed for racing, extended HI RPM, extended HI TEMP, HI Spring weight on the lifters. Once you leave the OEM parameters RPM,TEMP, and stress wise, these make perfect sense. The stock belt is just not going to last in the racing world as well, wasn't designed for that. The blue belt is.

I don't race, but I bet the racers on here will tell you they don't go anywhere near 3/30 on their belts. And in their situation the blue belt adds some leeway for their extreme usage.

Would it be beneficial to a street car... sure. It would be more resistant to normal stresses as well, maybe even improper tension. When the OEM belt fails before 3/30, likely it's not just a bad belt but some underlying cause. Would the blue belt have lasted? Maybe, maybe it would have died too.

That being said, with new rollers/WP and the works on my rebuild, I'm going stock. In 3 years, I may go blue. Then stay blue till I do my rollers/WP again. But I'll still go by the 3/30 rule.

 

Kinda curious where ECS got the 5/45 number. Perhaps 3/30 was for the originally equipped belts, and it got bumped to 5/45 after improvements were made to OEM?

 

I think that was the original numbers, back when the 944 first came out. I THINK I've read that's been corrected by a SB at some time. But I've never seen it, so I don't know.

Notice it says ECS and Porsche..... doesn't mention Gates recommended....

I'm sure even the OEM belt would be fine for 5/45, I know people have done it, and do it still. I've seen people post they do 6/60. It's just tempting fate in my book. The 3/30 seems to be working pretty well for the community, and they are the real world testers....

My .02

 

And wow, that's a nice kit. Just wish it came with the oil cooler seals.

the 944online one comes with all that, minus the blue belt and coolant, and adds full front seals and the oil cooler seals.

To me, if your doing the WP, might as well do the rest too. So the 944online kit makes more sense to me. But that's still a nice kit if you don't have leaking front seals and oil cooler seals....!

 

http://www.gatesracing.com/products/timing-belts

 

I really, REALLY think those things would be good for 6/60 on these cars....

But man or man, if I tried and was wrong

I don't want to do this rebuild again!

I also wish we could get to the bottom of exactly why so many of these (OEM/Aftermarket) belts break. Seems there is never a common cause, aside from maybe age. Maybe they sit too much, too often, as a second car? Most of the stories I read of snapped belts are not DD's, but weekend cars. Maybe sitting unused does something to the rubber faster than a more often used car??? Maybe we could make a thread, what miles/years and situations did your belt snap in? Or has that been done?

I would think the Gates would help a lot with that, being different materials....