Busted Fan Belt, Can't fit new one on?

[74cookiecutter]

I was having some fun in my Targa on the way to pick my wife and child up at her mechanics shop across town this afternoon. As luck would have it I was driving pretty hard and the fan belt busted, Temp jumped up to 220ish just as I pulled into the non-Porsche mechanics shop.

He said I'll get the new belt in here in 5 min and we'll get you back on the road.

Three belts and two hours later... no road.

The 10mm x 710 spec was too small to get the nut and pulley front back on. I expected the shims would need to be put back on but this was impossible.
We tried 760 and 765mm belts they were too loose obviously.

What's the trick to getting the right size belt back on? Could I have a different set up or are the new notched style belts not narrow enough at the narrow (inside) face of the belt?
See Pick of car and stranded family.

[Early_S_Man]

The spec for your belt is 9.5 x 710 ... not 10 x 710

[rnln]

I am confused on this too. Some said 10mm. Some said 9.5mm. Below is from Pelicanparts.com
74cookiecutter is a 74? it said right there 10x710.

Alternator Belt, 911 (1974-75), 911 (1980-89), 911 Turbo (1976-79), 911 Turbo (1986-89), 10 x 710

999-192-176-50-M21 $5.00
Alternator Belt, 911 (1976-79), 10x725

999-192-097-50-M21 $5.00
Alternator Belt, 911 Carrera 4 (1989), 9.5x776

[74cookiecutter]

I read the same and many belts have the 9.5-10mm range. Not sure if .5mm would make the kind of difference i experienced anyway.

What say you? Are most attempts by pelicans to replace these belts easy or difficult?

[74cookiecutter]

Correction: I meant 725 not 710 length belt
Sorry

[74cookiecutter]

Off topic query:
What is the protocol on wife spec listed? Car birth year is obvious but wife birth year or wedding year?

[slodave]

I have an OEM belt in my tool kit for my '84. It says: PORSCHE 999.192.176.50 9.5x710. I have been running 10x710 for a number of years without problems.

Dave

[KFC911]

Originally posted by Early_S_Man
The spec for your belt is 9.5 x 710 ... not 10 x 710

Someone else had a thread here in the past few days regarding the 10 x 710. That's the size Pelican sent me for my '88 (the belt I have on her currently is 9.5 x 710)....are they interchangable?

[Early_S_Man]

Keith,

Maybe ... maybe not! I have seen cases where the 10 x 710 will fit on worn fan & pulley half, but the fit will be tighter than a 9.5 x 710, since, by definition both have the same OD of 710 mm ... the 10 mm being wider will ride up higher in the pulley/fan groove, and seem like a tighter, shorter belt ...

[KFC911]

Thanks Warren! I understand what you're referring too as I have had the new belt on for a brief period. The inside portion of the new belt is also shaped a bit differently. In my case, neither the fan or pulley are worn. I'll try it again sometime (my old belt is still perfectly fine for now), and play around with the shims (since it is also a new belt). Thanks again for your advice! I sure wish Pelican had sent me a 9.5 x 710 though !

[Wil Ferch]

Here is what I posted in another thread... remember you must use 6 shims ( total) ... some under the head of the nut and some between the pulley halves ( for propr tightness), but always use all six in some combination this way....

here's the thread... --> Engine Fan Drive Ratio

-Wil

[KFC911]

Thansk Wil! I read your warning about not using an aftermarket 10 x 710 belt, and that's why I was concerned and took it off. I sourced mine from Pelican, and although I don't recall the brand name it said 'made in Germany'....I'll check them both when I get home.

[Wil Ferch]

Although I didn't do it lately....my most recent fan belt purchase was through a Porsche dealer and I got the 9.5's at a satisfactory price.

I don't recall the real problem that others mentioned who ran 10's when 9.5's were called for...but their problems did go away when the 9.5's were used.

Wil

[74cookiecutter]

It's fixed! Lesson learned. Don't use the Gates belts even though they say 10 x 725.
The problem appears to be the taper of the belt not the width or length. The Conti-SF belt supplied by the local foreign parts supplier went on with ease. it was marked AVX 10 x 725 LA. It rides just below the fly wheel top roll and fits snug with all six shims in place. Just like a new belt should.

NOTE: If you hear a high pitched clinking noise after your non-Porsche mechanic installs your perfect fitting belt. Check to make sure he put the shims on the fly wheel. I now have a cracked outer fly wheel due to stress and wobble at the arbor. $20 for the new one.
Hope it's ok to drive?

[greg bradbury]

I had the same problem last time I tried to replace a belt.
I posted a question and got 0 replies. Here's what I wrote-

Today I bought 2 x OEM fan belts. I have changed the belt once before and had no trouble. When I tried to fit the new belt I couldn't even get the pulley to sit back on the shaft let alone get the nut back on. When I looked at the old Vs. new belt the outside width was the same at 10mm but the inside width was different. New belt was about 7.5/8mm the old belt was 6mm. The old belt only has 10,000km on it and was being replaced as a matter of course. I went back to the parts outlet and they said the old belt was worn out.

Does anyone have a new belt that they could measure the inside width. The belt is a Goodyear brand.

Has anyone else had this problem?

I got excited when someone else had problems.

Thanks. Greg.

[74cookiecutter]

Greg, did you get a new belt to fit, or are you still having problems? is your belt a 725mm length? Mine should have been 710 but due to some unknown reason my '74 2.7L that was rebuilt in around 1983 requires 725mm belt.

If you need I can send you more info on the belt I used.

PS; While the board is great to seek and exchange information it can be a little non-responsive especially if you don't have a "buddy" watching out for you or you don't post a good hook title on your original posting. Also try to give a good pick of your car and problem. Detail pics always helpful. I would suggest calling Pelican parts and speaking to someone like Gregg ext 240. The sales and techincal dept has a good grasp of the issues that we face and are glad to help especially if they have sold something to you in the past.

[Ray B]

I'm not a "Porsche only" type of guy-except when it comes to fan belts. Go to a Porsche dealership parts department, spend an extra buck or two and save yourself some headaches.

[javadog]

The early cars used a longer belt. In 1980, it changed from a length of 725mm to 710mm. The width is given as 9.5 in both cases. For grins, I just measured a brand new factory Goodyear-branded belt from an '86 turbo. It measures a hair wider than 10mm at the top and about 6mm at the bottom.

Greg, I'd say the parts outlet is full of crap. Get another belt. They gave you the wrong one.

74cookiecutter, I am figuring that you are not talking about a flywheel, but either a pulley or the outer half of a fan pulley. If it's cracked, replace it, no question.

JR

[74cookiecutter]

JR, you're correct. I misspoke. not fly wheel rather it was the outer pully-half.
sorry.
I wish I had measured the inside and out edge dimensions of the fan belts I was sent by Napa.
But the German made Conti-SF brand fit with such ease I finished the job with haste and only did a visual check and noticed the inside edge width was a little larger on the Gates brand.

Yes I ordered the Outer Pully and a new belt Friday from Gregg at PP and it was shipped Friday PM.

Thanks Ray and JR for throwing your 2c in on this one. I'm sure others try to do this and run in to the same issues. Not all brands will fit, no matter what size they say they are.
When time is in short supply and the weather is nice I like my car to work. These are the things you wish you knew before you ran into trouble.

[rnln]

To avoid problem here any there. I think it worth it to go for dealer belt. Anyone know a local P dealer in Orange County SCal?