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Rasta Monsta · Joined: 12 Jul 2006 Posts: 11733 Location: PacNW

931 Timing Belt Fail "Nothing Major."
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Toofah King Bad

WeiBe (1987 924S 2.5t) - 931 S3

fiat22turbo · Joined: 18 Jan 2006 Posts: 4040 Location: Portland, OR

No title either.

BRILLIANT!
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Stefan
1979 924 Carrera GTS (clone-ish)
1988 944 Turbo S (Silver Rose)

jbwheele · Posted: Mon Feb 14, 2011 6:32 pm Post subject: Belt position on pulley ?

Hey is it just me or do all these Cam belts sit slightly off the front of the cam toothed pulley gear. My NA back in Oz had the belt is forward about 1 eight of an inch , the latest 931 motor im doin is the same, surely its supposed to sit flush or is the something Im doin wrong again?

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Joe
82 932 Stripped bare full rebuild
80 932 GT Lookalike Engine S2 swap

Grenadiers · Posted: Tue Feb 15, 2011 12:31 am Post subject:

Mine does the same thing.
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'83 944 Track car.
'88 924S Track car.
'89 944 Turbo
2004 Winnebago Vectra monster RV
2012 Jeep Wrangler
2014 Kia Soul
2001 Ford F350 powerstroke

Smoothie · Posted: Wed Feb 16, 2011 2:20 am Post subject:

Smoothies' belt on either side is not overhanging..

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"..it's made in Germany. You know the Germans always make good stuff."

'82 924T, US version, dark green metallic, 5 speed Audi 016G gearbox

Grenadiers · Posted: Wed Feb 16, 2011 7:25 am Post subject:

Do you have a spacer/washer behind that cam gear?
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'83 944 Track car.
'88 924S Track car.
'89 944 Turbo
2004 Winnebago Vectra monster RV
2012 Jeep Wrangler
2014 Kia Soul
2001 Ford F350 powerstroke

Smoothie · Posted: Wed Feb 16, 2011 11:31 am Post subject:

No sir.
-And no other forms of trickery-deceit-shanana-nanagans are being employed..

I'd first suspect your tensioner wheel and/or crank pulley since they guide the belt. (You wouldn't have put a washer behind your tensioner, right?)
-Or could your cam shaft be recessed too far? (Don't know if that's even possible..I'd suspect not.)

With some luck I'll remember to take valve-cover-to-cam-sprocket distance, and belt width measurements tomorrow.
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"..it's made in Germany. You know the Germans always make good stuff."

'82 924T, US version, dark green metallic, 5 speed Audi 016G gearbox

jbwheele · Posted: Wed Feb 16, 2011 6:55 pm Post subject: Yeah Weird

The Crank pulley is already touching the front of the belt or near enough, so if it relys on that then perhaps its the end float of the crank ? anyone else have a look for us and we should do a survey
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Joe
82 932 Stripped bare full rebuild
80 932 GT Lookalike Engine S2 swap

Smoothie · Posted: Thu Feb 17, 2011 4:11 am Post subject:

Measured with a caliper -
front surface of the valve covers' timing pointer to rear outer-most surface of the
cam sprocket wheel = 0.6732inch (17.1mm)
belt width = 0.7141inch (18.14mm)
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"..it's made in Germany. You know the Germans always make good stuff."

'82 924T, US version, dark green metallic, 5 speed Audi 016G gearbox

jbwheele · Posted: Thu Feb 17, 2011 12:48 pm Post subject: Mines 16.5mm

16.5mm..................
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Joe
82 932 Stripped bare full rebuild
80 932 GT Lookalike Engine S2 swap

jbwheele · Posted: Thu Feb 17, 2011 12:50 pm Post subject: sorry wrong line on ruler

16.7 give or take a mm
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Joe
82 932 Stripped bare full rebuild
80 932 GT Lookalike Engine S2 swap

jbwheele · Posted: Sun Mar 13, 2011 5:59 pm Post subject: Hey Ive Figured it out

Hey Guys I think the answer to Belt to pulley position is the wear and position of the tensioner pulley, If you check for lateral play (wiggle hard)

I moved mine back onto the pulley more by grinding the seating surface of the tensioner pulley mount so that when it is in the Belt tightened position the pulley now sits more upward angel thus pulling the belt back.......dont go too far cause the belt will wear out on the flanges on the ends of the tensioner pulley

hope this helps someone........I will get a new tensioner pulley one day
_________________
Joe
82 932 Stripped bare full rebuild
80 932 GT Lookalike Engine S2 swap