The Forgotten On

That conti belt fault is well known and the main reason why most check belt tension after 1K miles and re-tension thereafter.

GregBBRD

I obviously can't speak for others that use a 9201 tool.

However, I calibrate my tool before every use.....and after almost 40 years of using one (actually have more than one, which I can compare with if I suspect there might be an issue with one tool), I can take it off and put it back on 20 times and get the exact same reading.

Extremely precise, for me.

DKWalser

Hmm, I thought re-tensioning after 1,000 miles was Porsche's recommendation long before Conti belts were thought to be a problem. Am I wrong? (It wouldn't be the first time.)

GregBBRD

I'm not about to use one, because of the steel impeller, but 928 International sells a huge amount of these pumps, with an almost zero comeback rate, according to Tom and Mark.

Everyone needs to keep in mind that water pumps, by design, keep hot steaming water from leaking out of the engine/pump with a single seal.

One tiny "chunk" of debris that gets caught under that seal ruins the pump......any pump.

Water pump failures on a freshly rebuilt (cleaned) engine are very rare. Used engines are tougher...due to the debris sitting around the bottom of the cylinders and from the disintegrating head gaskets. Flushing these older engines seems to reduce water pump failures from leaks.

GlenL

Really? That's good to know.

I go one better: I don't change them unless they're leaking. My #1 car I've had for 16 years and it's on the original pump. I even moved it to a new block.

I've got a few used ones as back-ups. I think one is a real Porsche pump, too. Had it out recently and it turns like buttah.

Actually, I've got a later-style Laso on the shelf that's headed for an engine rebuild along with S4 tensioner, arm, pivot and brace.

Hey... If you put a stretchy belt on that "self-adjusting" tensioner will it over-extend and lose tension?

AO

umm... err... to be clear, that was said in jest.

GlenL

Really? That's good to know.

Fox_

I thought all belts stretched some after the first couple thousand miles?

GregBBRD

AFAIK, that is true.

The factory belts with the factory tensioner will stretch from 5.0 to 3.6-3.8 in the first 2,000 miles (using the 9201 tool.) The belt warning light comes on (very predictably) at 3.0 +/- .1 (on the the same tool), so it is extremely rare to have the belt light come on during this period (for "normally" driven cars....cars driven very hard may need to have the belt adjusted before 2,000 miles.

GregBBRD

Hopefully, Ken will see this and respond, but I've been told he has a new design (Ver. 4.1) that moves the Audi tensioner closer to the fulcrum, addressing problems with belt stretch.

I'm sure he can tell you if his latest version has enough travel to compensate for one of these "rubber band" belts or if you should use a factory/Gates belt.

GregBBRD

The factory recommends retensioning of a new factory belt at 2,000-2500 miles. I'm not sure I've ever had a client with a Continental belt have one stay on the car that long, so I can't tell you how long those belts go until they need to be retensioned.

Keep in mind I get a tremendous amount of cars into my shop with "belt issues" created by other shops. I will always install a factory belt (or Gates belt) when I redo the work, tossing the aftermarket belt and aftermarket tensioner mechanism (if so equipped) into the trash.

928Myles

I can see the dilemma here.
As a (I hope) responsible owner, I should encourage less responsible owners to buy the cheap pumps so that they ruin their engines For every engine ruined, my car goes up a notch in the rarity stakes, and, hopefully, in value.
The counter side of this is, assuming that these less responsible owners actually spend money to maintain their vehicles, that less parts will be sold and thus, the price of maintenance will also go up.

Nothing in life is ever simple.....

(tongue in cheek)
Myles

mj1pate

While performing the full up timing belt/Wp tensioner replace/rebuild last year, I noticed the timing belt that had been on for 10 years was a Conti. The tensioner light circuit was functional but never illuminated and a check on the conti tension put it right in the middle of the Kemf window. I replaced it with a gates. With all the glares at the Conti, I thought I would mention this. And of course, with the aforementioned in mind, I would still go with Gates.

Adk46

Has anyone ever tried to pre-stretch a belt before installation? I'm imagining two old gears and a come-along, in a heated box....

Of course, some of the apparent "stretch" may be from wearing off high points on the belt surfaces, that is, "bedding in".

Someone clever should build a motorized device to deal with both issues. Roger could sell pre-conditioned belts.

dr bob

I think I have the perfect set-up to "break in" the belts. Sits in the garage/workbay under a cover most of the time these days, but offers a nice in-service platform for that duty.

I used to describe "break-in" as the first intense stages of "wear-out" to fellow machine designers early in my job history. Curt, you'll appreciate the thought that there's no such thing as a "good" rub on initial roll. It may be that the belt is an exception. Why else would there be an air eductor system to vacuum up the belt wear fragments and deposit them in the air cleaner housing?