Tremelune

This may be way off base, but I searched and found no mention of it.

I just got done doing the belts on my Ducati 916 and to adjust the tension, I used a laptop and a mic to get them tensioned to 110 Hz when plucked (like a guitar string).

Ducati has a similar expensive tool for adjusting the finicky timing belts, but nobody wants to buy it. It was then I remembered 944 timing belts and special tools and what not. Now, I never did the belts myself on my 944, so I don't know if this is viable, but the theory is sound (no pun intended...).

As long as there was enough space to work with, it seems like someone with the Tool could record the proper tension frequency, which could then be used in lieu of the Tool forever and ever. Kittens and unicorns.

931guru

Excellent idea. Let us know how it works out.

gtroth

--always liked that idea. Pokey in this thread suggested simply using a guitar tuner:

http://forums.pelicanparts.com/showt...av+timing+belt

Wonder how well that would work.

krystar

so i can call over the piano tuner guy and have him tune my timing belt....how much are they an hour again?

V2Rocket

i just recognize by ear when it is too tight (higher pitch than usual means too tight - 8 years of violin and viola will teach you at least that lol)

generally its easier just to tighten the timing belt to the point that you can grab it at its longest span and turn it 90* with your thumb and forefinger. did that in 06 and havent had an issue since

Andy1212

True that. People treat these belts like they are some mysterious object that only works with magical tools. A belt is a belt, it just happens the consequences of a failure is a little higher lol.

Tremelune

The Ducati folk were using similar stretch/twist methods of tension. Adjusting by frequency is much more accurate. As to whether that extra accuracy translates to a safer motor, I don't know. A lot of the maintenance steps I take are as much superstition as anything else. I figure, if I over do it five times on five tasks, maybe one time it will save a huge hassle and be worth it.

I haven't heard of a belt taking out the motor of an in-the-know 944 owner that kept up with maintenance, but then again, I feel like most of us haven't been doing these belts ourselves. I no longer have a 944, so i won't be putting this in play any time soon.

I can tell you that tensioning by frequency is extremely accurate if you can get a good, strong tone out of the belt. From the posts above, it sounds very doable. I tried using an iPhone on my Ducati, and it just wasn't picking up or displaying the frequency very well. The laptop and mic worked perfectly, on the other hand. Certain guitar tuners may work, if you can plug a mic into it. I sure as **** couldn't do it by ear.

That Pelican thread referenced a different 928 page that is now dead. The remaining question is, what frequency should you be aiming for?

Yummybud924

yeah I wish there was an easy accurate way of measuring the belt tension on the 944.

I used the kricket but it doesn't seem very reliable pretty much the same as using the twist method. you'll get close but you won't know how close you are to factory specs.


I tried the arnnworx tool with teh gauge and that didn't work for me, the calculations would give me a super loose belt and I just used the twist method and took it to a shop to have it done.


now I have to go back for belt retension and I hate having to pay 100 bucks each time to have the belt checked.

StoogeMoe

This is actually not a wacky idea. Lotus used a similar device for their timing belts.

Here's one I found click here

Unfortunately, they're not cheap. Even more pricey than the 9201. But way easier to use. And probably more accurate. The only flaw I see to this method is the variation in belt construction for different manufacturers which would change the frequency.

67rschev

I have one of these , I call it the 'Twang-o meter' . I am going to do some tests to see what hertz tension a properly tensioned M44 motor should be at . Issue is , i dont have anyone local who has the ' ubermajic ' tool . I have found a fellow lister locally ,' Porscheophile ' has the Arnworks tools and he has agreed to help so we can see where the Arnwerx tool stands . I have a motor on a stand ready to go . Anyone local in Colorado have one i can borrow for an hour or, somebody not local would be willing to 'loan' me one ? Ill pay shipping and i will do a small right up .

trailpimp33

Hey 67 if you need another car to double check with I will help, my 83 needs a tension.

67rschev

Trail do you have the Porsche tensioning tool ? I realy need to find someone local who has it , or someone who will let us borrow it . You are more than welcome to come out and help . For this testing i think the engine on the stand will be easier to use so we can switch tools and take pics , but while we have all the tools together we can retension your car allso . Porschephile ( geoff ) wants to do his turbo too . I will pay for shipping and beerif any rennlisterswill let us use the P tool .... anyone , anyone ?

whalebird

Great idea. I have built several bicycle rims and use the "twang" method to get spoke tension even.
Remember... new belt and used belt have different tension.
I would feel beter with this method moreso than the goofy tools offered aftermarket.
I have a 9201.

yellowline

Mmm...no. When George Beuselinck says "use the tool," you know it's time to use the tool.

I've personally seen someone with a 9201 verify a local RLer's hand install of belts, and he's been in 944s for more than my 5 years. He got the BS belt right, and had ~1.6 on the timing for a new belt. The 2.4 difference in tension is significant.

KuHL 951

It would be interesting to see if each belt manufacturer has it's own distinct sound. Remember Ducati and Lotus probably only have one belt source. If you look at a 944 belt from Fleenor, Conti, and Gates you can see a major difference in construction. That would have to play a role in harmonics with the Fleenor belt sounding like the cheap POS it is. I've used the TB 90 deg. twist since my first 944 and have never had a belt be too loose or tight. BS belts are just a trial and error until you get the feel for how loose they really are.

It's just a timing belt not some Stradivarius for God's sake...people get so **** over such a simple devise because the factory sells a $600 tool.