shredded timing belt

montego6500

New Member
Apr 25, 2007
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Burlington, Wisconsin, United States
ok fresh rebuilt motor and everything in my sign. last night my motor started making a funny noise fron the front end. i was like whatever. got home today took both belts of motor (no a/c) and noise was still there. i was like shit. so i opened up timing cover and found timing belt shredded half way through. does anybody have any reasons why that would happen. the belt was new, it didnt break, i still have good oil pressure, and theres no oil like mixed in with the shreddings. the belt seemed like it wanted to walk to the rear of the motor. any help is greatly appreciated. sorry if this isnt tech enough.
 

natedogr

New Member
Sep 12, 2006
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Chatham, Va
or the timing sprocket on the crank could be on backwards. i've done it on my fresh rebuild and it started eating away at the timing belt. but if that was the case your front main would have blown out too.
 

CajunKenny

PULL MY FINGER. PLEASE!
Nov 15, 2007
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If the rear retainer on the crankshaft timing gear were to come off (like mine did) the belt would walk backwards and rub on the cam gear plate. You wouldn't know it until it either shreds or breaks.
 

figgie

Supramania Contributor
Mar 30, 2005
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Twin Cities, Minnesot-ah
ahh
i had this happen to me before.

and I think I see your problem in picture #2.

Check the oil pump pulley. More than likely the bolt sheered off and the oil pump pulley is wobbling causing what you see.
 

paradox616

New Member
Sep 12, 2008
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Melbourne, Australia
you can clearly see where the timing belt is being "shaved"

are you sure who ever rebuilt the motor A) used thread locker on the bolt for the oil pump & torqued it to spec? B) installed the crank drive gear correctly? c) followed the TSRM procedure for installing a timing belt and checking that the tension is ok?

the belt needs replacing anyway, pull off the balancer, front timing covers and find out what fucked up. then RTM and put it back together :)

Start from here, inspect the spring and the pulley
http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?S=EM&P=27
 

jdub

Official SM Expert: Motor Oil, Lubricants & Fil
SM Expert
Feb 10, 2006
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Valley of the Sun
There is another possibility: The crank drive gear has 2 thin washers tacked on both sides of it. If one broke loose (I've seen it) the belt will not guide correctly and chew it up like yours.
 

CajunKenny

PULL MY FINGER. PLEASE!
Nov 15, 2007
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jdub;1392441 said:
There is another possibility: The crank drive gear has 2 thin washers tacked on both sides of it. If one broke loose (I've seen it) the belt will not guide correctly and chew it up like yours.

jdub and I thought alike on this one! :naughty::biglaugh:

see post #5...
 

Dirgle

Conjurer of Boost
Mar 30, 2005
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Pauma Valley, CA
The first MKIII I got had the timing belt shredded like that. It turned out to be the pivot pin for the idler pulley had worked it's way out, and fallen down into the bottom of the timing cover and was chewing it up from down there.
 

CajunKenny

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Nov 15, 2007
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I'm surprised at how tough timing belts can be. Mine has had a hole in it for about 5k miles now.

I know...I know... :slap: