Do timing belts stretch depending on directional rotation?

There is no directional orientation for timing belts; for practical purposes there is no stretch.

Dino oil? I've heard of that. I seem to recall reading somewhere that it was used extensively until the mid 1970's.

 

Slow day on F-Chat? Bored at work with spreadsheets, computer code, legal briefs, pesky patients, business meetings, etc?

Liven up your life!

Start a thread on (a) the appropriate interval for timing belt replacement, (b) price appreciation potential of various Ferraris, or (c) what permanent modifications to a 308 are justifiable in light of performance or reliability.

Or ... you can just take a big stick and knock down a bee hive.

 

Naked!

 

And smeared in honey.

 

The belts don't stretch if you smear honey on the tensioner bearings, btw.

 

Are the belts leaking?

 

I know what is driving you bored at work...

 

Can't find beehives or wasp nests. This will have to do.

I haven't changed my belts since 2012.

 

I have been hesitant to post this because, well, it about belts. But since someone else started a thread on belt stretch, WTF! Below are pictures of two timing belts interlaced. The belts were clamped together at one end with the leading edge of the teeth on one belts snug against the trailing edge of the teeth on the other belt. Then the belts were each placed under equal tension. While under tension the belts were clamed together between two pieces of wood. The difference in belt length was then observed as a gap between the teeth at the other end. Here is the catch. One belt is unused, new if you will. The other belt has 27k miles on it. Here is catch #2. The longer belt is the unused, new one!!!! Now consider that belt length tolerance is 0.75mm. There are 3 extreme possibilities. 1) The belts were the same length when new. If that were the case the used belt must have shrunk, not stretched. 2) The unused belt was at max tolerance and the used belt at minimum when new in which case, the unused belt would be 1.5mm longer than the used belt when both were new, and the reduction in the gap from 1.5mm to what it is now is the stretch of the used belt. 3) The unused belt was at min tolerance and the used belt at max when new in which case, the used belt would be 1.5mm longer than the unused belt when new, and again, the used belt would have to have shrunk, in this case, 1.5mm plus the current difference in length. So draw your own conclusion regarding belt stretch. But the bottom line here is that after 27k mile of use the used belt is shorter by a skosh.

Have fun! Drive a Ferrari.

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It's just the variation within manufacturing tolerances for the belts.

 

Nope, it's all factual, that's why we toss our timing belts in the drier on high for an hour prior to mounting to get them to shrink enough so that we don't have to retime the cams.

 

You guys may not be aware of this, but a serpentine belt for a 2004 GMC Yukon is long enough to wrap around all 4 cam pulleys + the water pump and harmonic balancer on the 3x8.

The belt is also double sided, so it lasts twice as long. So then you only have to change your bills once every 7 to 10 years or so.

 

My 308 does not have belts anymore. I bought bigger pulleys and they rub against each other. When they start to squeal I hit them with honey.

 

I think that we have a winner!

 

No, no, you're doing it all wrong. See below.

Poking fun at Ferrari enthusiasts' obsessions is more fun than writing legal briefs. Too bad nobody will pay me for it!

No, no, you are doing it wrong. You have to soak them in equal parts honey, lemon juice, and Dino Oil. Let them soak for a good month or so. Then, lay them out in the sun to dry and shrink. Belts treated this way need not be replaced for at least 10 years.... actually, more like 12 to 14 if the honey and lemon juice are organic.

 

We need to clarify but one thing. When you say "Dino Oil" does that refer to oil that was used and then collected from a Ferrari/Fiat Dino or from non-synthetic sources?

 

Sheesh, read the stickies.

Obviously, drained from a Dino 246. But the best source for oil is a Posche 914 from BHCC. They sell the ones with the most vintage oil. And the older the oil, the closer in age it is to the dinosaur it came from. So far more pure. Check that the 914 actually HAS oil in it before you buy, though.

 

What kind of oil should I put in my Ferrari? RifleDriver suggested Walmart 10-40 but FBB said I would have to degree my cams once a week if I did.

 

Thats my interval with Ferrari belts.