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Old 01-09-2009, 10:00 AM
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Default T-belt broken in 3.4L

I have a 98 3.4L that the timing belt broke on. I now suspect that the pulleys are not lined up anymore and im not quite sure how to do that. Obviously the crank pulley needs to be at TDC but don't the cam shaft pulleys make two revolutions for every one revolution of the crank pulley? Thus there would be two differen't times when the marks on the cam pulleys line up, maybe?

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Old 01-09-2009, 12:38 PM
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There should be marks on the the crank pulley and the cam pulleys to assure proper alignment. The FSM should detail the procedure.
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Old 01-09-2009, 01:05 PM
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It does, and the new belt has alignment marks on it too.

Hint: you will need a special tool to compress the tension idler, and it would be a great time to replace that idler (fresh bearings) and water pump at the same time. Saves work later at a time not of your own choosing. Make sure the new idler doesn't have 'dry' bearings from the factory. Happened to me - twice. Bad run I guess.
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Old 01-09-2009, 02:17 PM
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So in essence what you guys are saying is first BUY FSM!

Second with every one revolution of the crankshaft gear the camshaft gears also make one revolution correct?
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Old 01-09-2009, 02:22 PM
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Originally Posted by daisydog34 View Post
So in essence what you guys are saying is first BUY FSM!

Second with every one revolution of the crankshaft gear the camshaft gears also make one revolution correct?
Negative ghost rider....cams spin at 1/2 speed of the crank. 4 stroke means two crank revs to every one valve movement. Yes....an FSM should always be in your possession before the temporary plate expires....at least thats my belief....
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Old 01-09-2009, 02:32 PM
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Negative ghost rider....cams spin at 1/2 speed of the crank. 4 stroke means two crank revs to every one valve movement. Yes....an FSM should always be in your possession before the temporary plate expires....at least thats my belief....
Thanks uncle ben that exactly what I was thinking, but nobody was understanding that my belt BROKE therefore its obvious to think that the three gears are not longer lined up. NOT the same as replacing a belt before it breaks.

Now that we got that cleared up anybody have any thoughts on how to line the motor back up so the timing is right, or is this where the FSM comes in to play?
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Old 01-09-2009, 03:51 PM
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Originally Posted by daisydog34 View Post
Thanks uncle ben that exactly what I was thinking, but nobody was understanding that my belt BROKE therefore its obvious to think that the three gears are not longer lined up. NOT the same as replacing a belt before it breaks.

Now that we got that cleared up anybody have any thoughts on how to line the motor back up so the timing is right, or is this where the FSM comes in to play?
Not to spook you more than you already are but the vz series engines are direct interferance style engines which means if the belt actually snapped you might have more damage than just the belt as if the engine still rotates when the valve are no longer moving metal to metal contact is not a good thing. Good luck..... BTW I just sent you a PM for something that shouldn't be made too public......shhhhh
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Old 01-13-2009, 07:00 PM
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The general consensus I have heard is that the 3.4 is *not* an interference motor.

Also - how many miles were on this timing belt when it broke, and do you suspect it broke due to old age, or some other factor?

Steve
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Old 01-13-2009, 07:41 PM
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The general consensus I have heard is that the 3.4 is *not* an interference motor.

Also - how many miles were on this timing belt when it broke, and do you suspect it broke due to old age, or some other factor?

Steve
'98 4Runner
Good to know but are you sure? Hard to imagine any hemi style head having a large enough piston to head gap to not be direct interference!
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Old 01-14-2009, 06:23 AM
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It is not an interference design, according to the Gates timing belt guide at http://www.gates.com/part_locator/in...cation_id=3598

Also, the 3SFE 16v Camry engine ('87-91) is 4 valve, belt driven, and not interference.

Steve
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